All of these are great tips, but let me tell you my experience. I have a 2013 Nissan Altima S with the 2.5 4 cyl. For several months I was plagued with the P0420 code. My mechanic tried all the usual diagnostic techniques, checking o2 sensors, cleaning the catalytic converter, even going as far as gutting the rear catalytic converter to relieve a suspected blockage. The problem not only persisted, it got worse. Instead of coming on every 150 miles or so, the Check Engine light came back on every 50 miles. I have probably spent around $500 trying to get the stupid light to stay off. You know what finally solved the problem ? As per routine maintenance, I removed and cleaned (I have a K&N) my air filter. I cleaned and re-oiled it according to K&N's instructions and re-installed it. NO MORE CHECK ENGINE LIGHT. After all the hours and all the money needlessly spent, the solution was to clean my freakin' air filter ! Something so basic and elemental, I didn't even think of it. The lesson here ? Check the most basic, cheapest stuff first. You may think you have a special car with a problem so unique, no mechanic has ever seen it before. In all likelihood, its something simpler than you or your mechanic realize.
Save the K&N for the dirt bikes. Use OEM air filters. I put original OEM air filter in my Lexus LS400 and now I'm getting better gas mileage. Switch to the OEM Air Filter and run a can of 44K Platinum by BG in a full gas tank. That got rid of my Check Engine light. My CATs have 278,000 miles on them. I always use 44K and it gets rid of my check engine light for quite a while. I use Chevron gas. My emissions test results way below the limit. Codes P0421 or P0420, OEM Denso O2 sensors.. Lexus tried to get me for $4000 for two CATs Ha Ha Ha Bozos
I had a similar problem. But it wasn’t just cleaning the Canon air filter it was also cleaning the mass airflow sensor. The thing that pisses me off is the three mechanics I took the car to when I was having these issues all they didn’t look at codes and replace parts. That’s what they are parts replacers. They have no clue how to diagnose anything on their own without a computer.
Definitely first step is basic maintenance and spark plugs. Then track down all vacuum leaks. After that make sure o2 sensors are good and finally cats as the last resort.
I got this code after changing spark plugs and ignition coils and driving about 50 miles or so. I've done the replacement twice already with no problem. No misfire codes just p0420 efficiency low bank 1. Any ideas?
@@thejagmohan7121 loose plug could cause it. You used the spec denso or ngk plug? If it wants platinum don't use iridium or vs versa. Some motors like the Toyota 3.4 are super sensitive due to the reverse polarity coils. Hard to know your situation based on the general post
After chasing my tail a number of times trying to troubleshoot a P0420/430 DTC, I would check the manufacture’s list of TSBs and see if there were any software/reflashes that might address the issue. Wasn’t unusual that new vehicles had very tight software constraints to get them certified and keep the EPA happy. After the vehicles amassed many miles through a myriad of conditions, updated programming via reflash gave the ECM a bit more elbow room to keep the MIL off. That “Silver Bullet” saved many of my customers the high cost of converter replacement. signed, One happily retired 35 year ASE Master Technician…
@@BobSmith-tn2qp he updates the software like downloading an update from the play store to the engine computer and loosens up the tight restrictions for whats allowed through the catalytic converter and sensors that read from it so it has more wiggle room and wont throw codes
@@rp6236 I would gladly pay someone to check out my truck that knows what they are doing. I want a guy that understands fuel trim’s and all this other high tech garbage. Last guy said 02 censer and that fixed nothing. I would also like someone who knows how to tweak the computer. I haven’t found anyone yet other than part changers. Hell I can do that! I did fix the track control problem. My tires looked good but I you really look closer one was separating. As soon as I pick up speed the one wheel would throw a code. New tires a it never set a code again.
I’ve been ase cert tech and service manager over 40 years and the only fraud l’ve seen is poor diagnostics and ignorant owners. Most cars and trucks thru the shops l’ve worked have hundreds of thousands of miles with original converters working as designed. Not a perfect system, but the best we have if we want to continue burning fossil fuels. Basic maintenance consistently performed is enough to keep most issues at bay. There will always be exceptions and poor designs and manufacturers.
@@arthursmith1732 So my car is 17 yrs old with clost to 200k miles. The stock cats are no good they have lasted for as long as they could now throwing P0430 and P0431 trouble codes. I'm in California where it is illegal to install EPA cats. Plenty of those availalable but no retailer will sell nor ship EPA cats to Cal. Politicians will only allow approved CARB cats as replacements, none that exist in their database for my vehicle. I spoke with the state emissions rep they said my only option was to junk the car when there is nothing else wrong with it. Many others are going through same issue in my state. I don't see how this is caused by ignorant owners
@@JYAN2852 I knew you were in commiefornia when i saw your first comment! Im also in this ridiculous state and i have been going NUTS trying to get my damn van smogged! Ive scowered the internet looking for the right damn cats and when i finally find some, THEY ARE THOUSANDS OF DOLLARS!!! Thanks a lot gov newscum!! I hate this state cus of that commie bastard! Ive tried cataclean a few times and paint thinner too! Damn light keeps coming on at or before forty miles! Ive put TONS of money into this van and i will be damned if i am gonna scrap it!!
Several years back I followed Scotty Kilmer's advice for a catalyst failure code. Added acetone to a low fuel tank and ran it. The code resolved and never came back.
Got the code on my wife's car. They tried to sell me a converter. Then I realized it happened after daughter put gas in the car. So I checked the fuel cap problem solved didn't even have to replace cap. May God bless everyone!
I think this is what's going on with my car. Either that or because I got gas from a place I don't normally go to. Came on the next day after I got gas and it seems like my gas cap isn't getting vacuum sealed when I put it on
@leslielucci3182 Somehow, she didn't get a good seal ,nothing wrong with the cap. You're supposed to turn cap until it clicks, then turn, I believe, one more .time.
@@billybarnes9208 the cap to my Subaru is lost because the “string” attached to it broke and when my teenage son took the car on a long camping trip, the cap was forgotten at one of the gas stations upstate NY. So far I haven’t replaced it because car drives fine without it. The 420/430 code existed back when we had the gas cap.
experienced an interesting one in regards of this code P0420…it wasn’t my cat at all but rather it was the oil leak that spread under my car due to negligence oil changed my oil guy did…my Hyundai dealer discovered it and saved me $4K of cat repair costs…it was a breath of fresh air after I learned about it
Yup I've seen that happen. Some cars have oil filters located directly above (or close enough) to the upstream 02 sensor and that oil filter can be in a very restricted spot in which you don't have much of a choice but to make a mess when you remove it. When that happens it's very possible for oil to leak/splash/drip on to the 02 sensor and eventually work it's way through the threads and contaminate the sensor. I've seen this mentioned as a common issue in several car threads to the point that many car owners of that particular make/model started doing their own oil changes so as to not have to deal with the P0420 shortly after each oil change. This is also a perfect example of why it's so very incorrect to assume when a P0420 code pops up that it's the cat. The vast majority of times I've deal with that CEL code, I've been able to resolve it other ways. Only once was it a bad cat and that was within the warranty period (luckily) and it was also quite obvious that it was the cat because it sounded like a metal can full of pebbles sliding around under the car when coming to a stop or accelerating indicated a shattered catalyst. But every other time, it was not actually a dead cat and the resolution was usually relatively simple and a fraction of what it would have cost to replace the cat and/or sensors.
@@jludtxs I didn’t clean it myself but I noticed when I brought it to my mechanic and told them about it…they air pressured hosed it underneath with some water and wherever the leak was coming too from the sides
@@keithburningbush6456 Can you elaborate on that? I'm a backyard but capable student. But I don't follow your tweak there. Are you saying they spilled a lot of oil? or something else? Just wanting to learn.
Just a heads up, injectors on a direct injection engine are under such tremendous pressure compared to port injection. Injector issues on DI engines can actually cause compression issues. If DI injectors are ever removed for any reason, they must be replaced with a new injector to prevent compression issues.
I had this code on my Chevy Cruze LTZ. A fresh set or plugs and a new coil pack solved my issue. 170k miles. It was due for a tube up. $200.00 we’ll spent.
I just got my 1st Autel today. MK808BT. So far I'm loving it. Just changed a bad ABS module and was able to flash it and fix my abs lights in my town and country 3.8. This 0420 code is all I have left and both 02 sensors are new so I'll be checking out the converter. Awesome video. Thanks
I think the point of the video is that just because a code is thrown for a certain component, that component itself might be the singular issue, having lived it’s long life, and time to be replaced, like spark plugs, ignition coils, batteries, brakes. But more often than not, by a large margin, the actual cause is because of another component which is malfunctioning and it’s symptom is causing a reaction in the component that is represented by that code. You could replace that component every month and still not fix the problem.
Can't tell you how much I appreciate you posting this. Your presentation is professional, and instructions thorough and detailed. Unlike other videos with "quick fixes" that are on par with slapping a band-aid on a gunshot wound, you covered what's most important: the root cause(s). I was able to determine the state of my cat (spoiler: it's failed 😅) before my lunch break was finished. Thank you again for a fantastic break down. I look forward to your future content!
An extraordinarily smart and kind gentleman, he explained the basics and specific things. My Charger's converter was sentenced by "professionals" in the dealership, but it turned my engine was running lean due to wrong calibrations. So, I got my PCM replaced and the P0430 code is gone and not coming back.
My PO 420 code came on due to a Fram extra guard air filter that I had just replaced went back with original equipment Motorcraft air filter in PO 420 code went away, not saying that there’s not some underlying issue but that’s what removed the code on my 2018 Ford F150, 2.7 L.
I just took out the motorcraft air filter and put one of those red STP air filters in. Now I have the code 2 days later. Interesting. By the way I had thought of this possibly being a problem and had already ordered a new motorcraft. The STP FIlter was new when I bought the car but changed it out in a few days to motorcraft.
@@serchizmit is a threaded pipe that threads into the O2 sensor bung and the sensor is threaded into the end of the pipe. This puts the sensor outside of the exhaust stream helping to have a steady O2 reading on the secondary O2 sensor and avoid throwing a code. On some cars this works and some it won't.
This is a logical troubleshooting process ... and one I cannot see the typical independent or dealer mechanic spending time on. Two dealership techs independent of each other relied solely on DTC readers -- and incorrectly diagnosed the need to replace both of my 4Runner's cats and related sensors due to severe loss of power. Neither fixed the problem. An independent could not identify the source of the problem, either. Finally, my old-school pre-ECU carbureted background whispred "fuel pump," and I insisted under emergency circumstances that it be replaced even though the dealer tech was very leery. I was right ... but also several thousand dollars lighter in the bank account. Apparently, a bad fuel pump will not send adequate fuel, causing lean codes that seem to DTC readers to be cat-related. The lesson is that typical techs either cannot or will not do the kind of research outlined in this valuable video.
Their is no possible way that I know of for a lean code to be determined as a cat failure. Whoever you took it too either did not know what they were doing or knew exactly what they were doing! Did you receive your old cat back?
@@jeffflanagan2814 No, I did not. Didn't even think to ask. It was a bad situation all-round, but it is fixed now. I the end, I have two new cats with sensors, all new oil-control valves (another misdiagnosis, but they were indeed in poor shape), and a new fuel pump. All this at less than 160k miles, not what one expects with a 4Runner.
That is a brilliant way of troubleshooting exhaust leaks! Beats my way of crawling under the running car and running a bare hand around all sides of the pipe/joints trying to feel a leak...or waving a cigarette around looking for the smoke getting distorted (which, since I switched to e-cigs, is a lot trickier 😃)
I have an 02' Blazer zr2 4.3ltr. Got a new Cat, Rotor, Coil, ECU, Wires, Plugs, etc. My Check engine light came on & got the 0420 code. Exhaust is new also. It showed Bank 1 below temp. threshold. I changed bank 1 02 Sensor & same code came back. I do have another 02 Sensor located on Bank 1 Sensor #2, the 1 just before the new Cat. I'm installing a new 02 Sensor there today. No leaks, etc. Everything I had installed has less than 400 miles. The Cat is a high flow, Flowmaster Cat & the Mechanic Shop said it wouldn't throw a code. Zero power issues. The Truck is running great even with the light on.. I cant even feel it idling at a red light with the AC on!
Unfortunately, that might not be true about the new cat throwing a code. One reason why a few states require cats certified by CARB. What is the code number that you are dealing with?
I've read several comments and agree there are several different causes. But, for me, the code is for Bank 1. This means that the side of the engine with Cylinder 1 has an issue. Therefore, it does not seem like common components of the engine are at fault - such as a dirty air filter or MAF. It seems more likely that the issue is related to that side of the engine and it's combustion, oil, gas, adn exhaust components. Has anyone had an experience where the code specifies Bank 1 but it was not necessarily fixed by a component related to Bank 1?
@@YakanAutumn My car has the same, P0420 Catalyst system Efficiency Below Threshold Bank 1. I just saw a video that said to try the Catalyst sensor, so i just bought it and will put it on. Hopefully that will fix that damn ISSUE!!!
In the North East we most commonly see faulty converters. Exhaust leaks will show up in the fuel trim data, if theyre affecting the converter. Exhaust leaks are audible, and traceable in fuel trim data. 95% of the time, its a bad converter BUT the first step is to replace the rear o2 sensor, then the cat if code comes back.
From one old man to another, this car mechanic has aged just right; using his experience to not overprice customers and make sure the origination of the problem is cured, not just the symptom.
Have an '04 4Runner V6 4.0L. Had 420-430 and 206; cylinder6 misfire. The #6 plug looked oily- Checked compression 175 psi. No loss of coolant or oil. Good compression. Installed new valve cover gasket set. No more 206 code . Still had 420-430- ran a couple of bottles of cat cleaner & one gallon of lacquer thinner through the engine, per "Scotty". No help there. The 4Runner runs like a banshee. Very quick response. No sluggishness. No foul smoke from the exhaust. No issues with exhaust leaks or vacuum leaks. Changed both downstream sensors & added spacers to the downstream o2 sensors. No more 420-430. Passed smog, then I removed the spacers. Ran good for about 2 weeks before the 420&430 reappeared. I will reinstall o2 spacers (also known as spark plug anti-fouler); you can buy o2 spacers on line with out having to buy two 2 spark plug anti-foulers per o2 sensor, then having to drill the outboard fouler to accommodate the o2 sensor. Just buy the spacers on line. they are cheap & install easily. They come from China, so may take3-4 weeks to receive, but they can work. no guarantee, but cheap enough fix & often times does work. If the problem does not go away after I reinstall the spacers, I will buy a pair of new after market cats- For the 4Runner-they are multiple listings on eBay & Amazon. Any reluctance of the seller to ship restricted state (like mine: CA) I tell them it's for my ranch truck, not registered. They will ship it. They want the business~😁😁 There are YT vids on the spacer install and the anti-fouler method. search them out. Some spacers actually have a mini-cat screen in them. Again-they are cheap.
My check engine light hasn't turned off in ten + years. I finally gave up on it. I think they exist to get people to empty their wallets on worries that don't exist.
Finally....a REAL teacher who even speaks English that is understandable. There are dozens of these video's here on UA-cam that are pure GIBBERISH....or.... BROKEN ENGLISH as I never understood a word. YOU are a great teacher sir. Thank you.....
I bought 10.00 of gas at Ingles Grocery where I live. Approx 5 minutes later the check engine light came on. I had it checked at Advance Auto and OReilly. Both told me it was the code to replace the catalytic converter. My 08 Prius was running fine so I just kept driving it and the next day the light went off! So maybe the O2 sensor is going bad but don't just run out and buy a cat until you know for sure!
As a "seasoned" auto tech, I have had trouble at times with the P0420/430 codes. Most of the time, it ended up being a bad cat convertor as you can watch the downstream O2 sensor switch as fast as the upstream: This almost always indicates the convertor is bad. I have found air/exhaust leaks to cause it, of course and I have found a similar test: You can use the evap "smoke" tester in the exhaust. This has saved me many times. Also, many aftermarket convertors are made cheaply and not as efficient as the correct factory unit. I've installed these and had the same code reappear. When I finally convince the customer to spring for a factory unit, the problem goes away - Just sayin
In my case had more voltage from altenator and make ECU to read false from O2 sensors the car has 240.000km or 148.800 miles , when fixed ( altenator ) P0420 code gone after some miles , without erase from ECU .
I love your videos very knowledgeable! Learn a lot from you sir! My name is TASHA from USA 🇺🇸. My check engine light reads that I need to replace ignition coil and spark plugs as well as a cylinder 4 misfire secondary DTCs, p0420 cat efficiency helper threshold bank 1 and 83-13 ECM/PCM relation failure. I have a Honda Accord 2009 LX. I’ve driven like this 7 years! Now I fear how much repair will cost. Why me? 😩
I love your videos very knowledgeable! Learn a lot from you sir! My name is TASHA from USA 🇺🇸. My check engine light reads P0304 a cylinder 4 misfire secondary DTCs, and P0420 cat efficiency helper threshold bank 1 and 83-13 ECM/PCM relation failure. I have a Honda Accord 2009 LX. I’ve driven like this 7 years! The Engine Light Has Been Solid For 7 Years. Should I be worried? And can I keep driving like this without risking my health?
We had this code and a mobile mechanic was able to use his professional scanner to show the two banks, upstream and downstream measures, etc. It was very helpful to see this info vs. guessing. We got an OEM cat, replaced only 1 cat of the 4 (thanks 4Runner), and no more code.
The P0420 in my car was caused buy a combination of a worn donut gasket at exhaust manifold combined with worn engine mounts. Code would popup when driving up steep hills. Downstream sensor was reading lean. A new gasket and mounts fixed it. Vehicle is a 2006 Toyota Matrix 4WD with 226,000 miles.
Cristal clear,very useful info,as you say sometimes a cat issue is tricky to confirm .. best video and explanation about cat issues i see... Keep it up. Greetings from Spain 👌✔️
I sprayed down the flex pipe with soapy water and it started to bubble up .I currently have a p0420 code .I’m going to repair the flex pipe and hopefully that will solve my CEL.
Very likely it will. That is letting air in and throwing of what the sensors are seeing and could even cause the cat to overheat because of the leaning out of the feed gasses. Let me know!
So it's an exhaust leak. That makes alot more sense. I knew there was a Crack, and my tailpipe dropped a bit this last week and now it's running like crap and throwing those codes. Thank God I was already ordering a muffler
Looking at the same solution as well, seriously. My new to me '07 Honda Odyssey has become a money pit. I've had a bear of a day and your comment made me laugh, thank you!
Cat cleaner removed the check engine light on my old lexus. But the VSC ON OFF lights still on (which go on in Toyotas when the check engine light goes on). Any ideas?
In my experience most of the time I’ve seen these codes it did end up being a bad cat but I have saved my customers a lot of money on occasions where it ended up being something else
You haven't gone far down the rabbit hole of OBD diagnostics. I'm sure you find bad Cats BUT that's not what his message is. Like the Trainer has said "Cats are built for a lifetime. It may go bad, do you just replace parts or find out why it went bad to fix the problem." I'm putting my money on the fact that a Technician finds what has caused it to go bad. Any takers? Trust the code, check the circuit , Make the repair.
@@christopherfoxwallace1291 💯 agree with you on this but this code is a hard one to crack due to the amount of inputs that can trigger it. I have tried multiple times to get rid of it even with a good cat and had to try various things to get it remove.
@@christopherfoxwallace1291 I've replaced the (2) converters on a 99 4runner 4 times in 3 years. I gave up after 3 sets in the first 4 months i had it. Nearly one thousand into diag else where the last 2 years and no luck. I take it in specifically asking for why its damaging the cats and they come back with "replace them." Or my favorite "P0420 is always a converter failure." I pay the diag and onto the next shop. As much as I don't want to pay because my question goes unanswered, they still worked on it so I respect that. I gave the first shop that replaced them a second chance and they installed their best cats yesterday. 4 hours later it was back...in for a diag next week. Fun times.
Carbon buildup can also trigger Code P0420. My 2014 Jeep Grand Cherokee Laredo threw up the code even tho the o2 sensors and cats were good. So I thought hmmm what if it's carbon buildup? Got 2 cans of Seafoam intake cleaner, followed directions and after it blew all the carbon out the check engine light shut off and P0420 was gone forever
being a 00s chrylser guy (with several in my fleet), i'm very familiar with the O2 sensor outputs and their readings on my Autel MS 906Pro. However a friend of mine had the "dreaded" P0420 code pop up on her Honda. The software on the Autel doesn't report Honda's sensors (2013 Odyssey) in the same way, so I was struggling to help her diagnose, is it a bad cat or a sensor problem. Curiously, the MIL went out on its own, and the code was stored as permanent, but not active. In fact, I had to use EOBD to read both sensors, with the downstream in V and the upstream in mA. My educated guess is she has a bad upstream sensor, and not a bad cat. I came to that determination based on comparing the upstream data between both banks, and noted that bank 1 would occasionally be "smoother" than bank 2, instead of roughly tracking the same, and even once go completely flat line at 0 mA. I considered a possible wiring fault, but the fact the traces look like a sensor getting "lazy" or "falling asleep slowly" then suddenly "waking up", makes me lean towards a failing sensor rather than a wiring issue. The downstream sensors would also follow the upstreams in their reporting and graphing. Where would a DIY shade tree home owner mechanic go do to find more information about specific vehicles and their expected O2 sensor outputs and performance.
My P0430 code has become intermittent. Today was cool outside and tonight the temperature is 45 degrees outside. And the code on my dash went off. I just replaced my O2 sensor 2 weeks ago and it seemed to work because there was no engine code. Then 2 days ago the light came on and now tonight the check engine light was off again.
Pete, if you can help .... @5:24 the the AFS stream 1 graph seems behaving normal and lower stream graph is at constant zero....is it due to narrowband sensor has not achieved required temperature to give its output???
My 2018 Dodge Journey has the code and Drives sluggish…it always seemed to have since I got it new in 2019. I changed the nasty engine filter. Anyways, this video was helpful in understanding the mechanism of the CC and the code. So begins the “journey “…🤣
Have the p0420 code on our 2012 honda pilot. Started bogging when trying to accelerate. My 1st guess was bad cat. I was hoping a bad 02 sensor or air filter but with it running crappy im quite positive its the cat. Which really sucks
My experience with p0420 is usually a ignition issue or an exhaust leak at the manifold. There are other possibilities but in GM platforms it's more common to have high mileage plugs or worn / lose exhaust pipe to manifold seals.
Probably not the cause but my ‘98 Corolla was less than a year old-still at the Dealership Service stage-when someone forgot to re-fill the oil tank after a change. My mechanic kindly rebuilt the engine and the code began soon after.
Helpful information! I have the Autel AL519 which told me I had an issue on Bank 2. I deleted the code after checking the front & rear temperatures, as the drivers side seemed to have a wider difference between the two (which I believe is bank 1) as I have 2 converters on my F150 pickup. Interestingly, it's been a week, and after having the initial code come up, it has stayed off, although I will test again today. Thus makes me wonder if it was a random code that popped up for some reason? Nonetheless, it's something I'll be keeping an eye on. Thanks for the video! Having 137K on the truck, I would imagine the converters 'may' be getting to the end of life, but I'll continue to watch for check engine lights. Fuel mileage hasn't really changed either.
07 jeep jk 3.8 air temp intake senor was bad took out passenger side converter. Never threw code about sensor. Also had rad fluid leak on o2 sensor caused 420 code
My CEL light shut off on it's own after one day. Freeze frame data from when the code set reported my RPM at 3950 in a low gear. I did recently get distracted and forgot to shift (manual trans). I would have thought the PCM would ignore that. I will do the other checks in the video just in case.
You FORGOT to shift? Really? I've only ever driven manual transmission vehicles and shifting is automatic (no pun intended!). It's about muscle memory, not just remembering to shift.
On a 2006 ford crown Victoria police interceptor I have a PO420 code catalyst below threshold. I smell an exhaust leak, and per the scan tool one sensor is dead, and cat has reached 1650 degrees. Would you say that was enough to damage the cat beyond saving? And I'm taking it the leak gave too much air, this too much temperature? Pleeeeaaaase help! I know you kind of answered my question in the video
Take care of what you definitely know is bad, clear the code and rerun the monitor. It is possible that the cat overheated but the only way to know for sure is to take it off and look through it OR use a thermal imaging camera to look for signs of melted substrate. Yes, air leaks are like excess fuel - either causes the cat to run hot.
thanks for the great explanation ... there MUST be a better way ... amazing engineering to make a car a car ... but it's WAY too complicated ... and expensive ...
I got the check engine light with Po420 code but every time I drive 45min-1 hour on the highway the check engine light goes away for a day or two then come back on?
Also look for factory TSBs. Could be software issue. Some aftermarket cats aren't loaded correctly which can lead to a comeback or cat monitor to fail.
Also, should I run some heat through the truck because I have been running crappy gas for economy and this problem started after the outside Temps reached -15 and it wouldn't start. I "think" it's the exhaust leak, but water in the motor that froze probably added to the issue
I have a 2008 infiniti Ex35 which had the P0420 code. Was diagnosed that the cat's needed to be replaced, as appeared to be clogged. Replaced cat's. However, I now have extremely, poor gas mileage. There are no error codes. Any idea what is wrong? I am so confused that the cat's were replaced and now my fuel use is up by 30%.
I have the code thing. But an expert said he could fix it for under$220. So then I'm thinking that it could be the O2 sensor because my mileage is about 178k and they might go out around 150k or sooner. I saw one for about$170 and the guy said he could fix the problem for $220 so I think maybe that's what he was going to do. I hope that's the problem then I could just do it myself.
Be careful - without performing a proper diagnosis, no one can tell you what they can do to fix it. With the mileage on your engine, it could be a number of possible causes, including the converter. Seek out a more professional diagnostician.
Long Term is the window of time the adaptive memory dictates the fuel trim, Short Term is live data calculating to learn the parameters for the adaptive memory to update the Long Term. The O2 sensor signals rich below .45 volts & lean above .45. The Engine Controller only cares about that threshold & uses that to determine fuel trim. .. in other words the computer calculates the % of time that the O2 sensor is past the threshold of .45 volts & does that each time the threshold is crossed.
that’s the most intelligent description of some of the many, maaanyy, sorry gramr - thats SUUUUUPPPPEEERR DUUUUPEER mind boggleingly many deferent causes of the dreaded p420☹️.. makes me want to go to a mechanic, except most of them probley don’t have those tools✋(& if I asked they’d probley just say ‘whooos the mechanic here?.. hmmnn - don’t worry about it weeeve got it covered’) which means probley no .
I had my engine replaced. Three days later, the engine light turned on. They checked it twice and they said catalytic converter needs to be replaced. I was told it might came from the bad engine and ruin the cat. It costs a lot to fix it. I used cataclean and the engine light turned off for 3 days but came back on again. They trying to charge me 3500 for it. I can't afford it. Trying to figure out where to take it for a cheaper price
Any success? Cataclean, 1 gal lacquer thinner, Gumout with PEA, point is to clean out cat. Sometimes you have to clean it 2 or 3 times. Then I would clean it replace O2 sensors.
2011 Camry le all stock n 390k miles all original parts. Could not go up a hill but flat driving ok. Seems to lack HP too. Never change trannie fluid, so I'm I'm getting code for torque converter n code for shift selinoid. Non of this has to do with emission right? Check light on n off n p0420 for cat was another code. With these Toyotas, the manufacturer messed up as it is known to lose oil. The pcv needs to be replaced to solve this. Since it is leaking oil but not dripping on the ground, the oil goes to the exhaust n can clog the cat. I had a smog ran with co2 being 0 but hc was 15 so it failed emissions. Now getting a new cat would not solve the problem. Maybe I'll pass smog upon getting a new cat n can drive for 2 more years b4 I'm up for another smog. Eventually the new cat will get clog up as well so he's right when he said that the underlying issue needs to be addressed first. Plus with mine at 390k miles, maybe it is time for a new cat or get a newer car. Over 2 Grand just to get a cat replacement with mine. Fixing cost more than the value of the car so why bother? An option is to get cataclean bottle as it may help with the carbon build up n hoping to get that smog pass. California I tell ya. If this was MN where no smog is needed, I can go as high as 600k with this gifted vehicle. Oh n another way to test to see if your cat is good or not is to get a heated thermal laser scanner. You take the reading of the top of the cat, the middle, n the back end. Top should be hot, middle hottest n the back should be cooler. If the Front is the hottest then you have a clogged cat as heat has no way to get out from the backend so it travels to the front n that can do damage to whatever parts there are on the front like header n pump n whatnot to give you an overheating vehicle too.
I do all of my regular maintenance but got the P0420 code after refilling my gas tank. Thought it was the gas cap, so replaced that. Cleared the code. It came on again several hundred miles after I got low on gas again. I cleared it again. Drove around for a while, checked and even passed emissions. Then 3 days after emissions passed, low tank of gas and code came back on. What is the deal here? My car runs great btw.
Many monitors will not run when the fuel level gets too low. I'm wondering if that is impacting your issue. What is the year/make/model/engine of the vehicle?
Good day thank you for your help I need to ask you some explanation about a car that have no problems but don't have a power enough to climb up the street .thank you
If it has no power than it has a problem. Any work done recently? Have you tried dropping the exhaust ahead of the catalytic converter to see if power is restored? What tests have you done?
O2 sensors are recommended to be replaced 100,000 MI. By the dealer and the manufacturer and the mechanic. You can look use some of the cheap scanners that can show you a live data. Of the O2 sensor
hello, just found this video and was reading through the comments. I have a 2004 Toyota Sequoia and I had my 02 Sensor replaced few months ago and the catalytic converted (bank 2) replaced few months ago [aftermarket one]. The check engine and VSC alerts popped up again this week. Took it back to my local mechanic. He think it has to be a Catalytic converter from the dealer so he said he would check with them on the price and get back to me. He says its okay for me to drive in the meantime. For the solution can in your video, what brand do you recommend for my vehicle? 2004 Toyota Sequoia. thanks in advance
Hey, I have a 2012 kia soul 1.6 standard transmission. I've been having the same code popping up after each part replaced. So far we've replaced the knock sensor, the MAP sensor, all four spark plugs, the upstream and down stream 02, and the p0420 and p0420 p, keeps coming back. I hate to guess but I'm thinking the Cat may need to be replaced? Not sure what to do. Any thoughts?
Will aftermarket catalic Be a cause for p0 420 code I have a 2012 bmw 135i and can’t pass smogg it actually had a aftermarket air cleaner aswell Im putting and buying oem parts and see if that will help Any suggestions?
Sorry for the late reply. Look for a cat that is CARB certified. NY and CA require these to be used as replacements. "Universal" cats won't do the trick.
I got some strange readings on for my p0420 sensor. The cat gets a green check mark and the 02S does as well but the EVAP isn't hitting the mark. Trying to get this car smog ready and out of Non Op but this is the wall I'm hitting. Changing spark plugs tomorrow but idk if it'll help.
I think you are referring to the monitor status for the various systems. The EVAP monitor can be the hardest to set. What kind of vehicle is it and are there any codes?
My 9 month old after market converter was rattling like a stone was in it. (No codes). My mechanic said he could not check any readings because he said back pressure was present. When I asked what the back pressure showed he had no data. Just said he could hear it leaking. He said looking at engine data was useless due to the back pressure and said the cat is obviously broken so he would not be able to test until a new free flowing cat was installed. I basically paid 200 for a diagnostic that he did not do and said he couldn’t do. Is this even right? I feel like I got swindled. I did my own fuel trim readings and my long term fuel trim was around -3.6 on a 20 year old car. That does not me seem bad enough to create a failing car so fast. He also claimed he could hear material down stream rattling around the resonator but I took apart and it’s completely free of material. Doing a pressure test later today before and after the cat. Going to be pissed if I find no issues. I get the catalyst may have broken. I can hear it in the cat when I hit with a rubber mallet. But that’s not what I paid him to figure out.
First thing to ask yourself is, "Did my battery go dead or did I replace it?" Sometimes you have to perform a "Drive Cycle" specifically for your car so your computer can run a "Readiness Test."
@@kariniemannfuss9208 You are a prime candidate. Just Google " Drive Cycle" for you vehicle. You could get one from GMC or your mechanic. On my Tahoe I had to let it idle at a specific RPM for a period of time from a cold start with a number of electrical items turned on and drive it a certain way to allow the computer to scan all sensors to know that everything was working properly. The codes switched off and I was able to get the emissions checked. As far as the no start, you'd have to check with diesel forums with your specific issues. Sounds like a computer communication problem. With no power for an extended period of time, the computer might need to be reprogrammed.
If you install those Sensor Thread Adapters to get the O2 sensors out of the exhaust stream, will that tell the computer that the mixture is too lean and enrichen it causing lower fuel mileage?
Car threw a P0420, I installed a known good catalytic converter ( at least it was good on my old taurus, no codes, before giving car away ), car threw P0420 and P0430. Checked exhaust for leaks, found flex band mesh was deteriorated but rippled metal pipe inside was intact. Replaced O² sensors and spark plugs, checked for coolant leaks, checked coolant temp sensor. OBDII scanner shows catalytic converter passed and green, but evap monitor flashing red and check engine light in on. Where do I go from here ?
@@MotorAgeMagazine thank you for responding so quickly ! P0420 and P0430 My scan tool shows that cat has passed and is green, but evap has not passed and is flashing red ?
@@MotorAgeMagazine i also graphed live data and bank 2 is normal fluctuating upstream and flat lining downstream, but bank one upstream and downstream are mirroring each other.
@@paulpurdue5963 beware that it takes a couple driving cycles to complete the MONITORS after an ECU reset. If you have over 90+kMi REPLACE the 02/Lambda UPSTREAM SENSORS as they get lazy yet without a DTC code for failure. These tired lazy sensors cause vibrations in V6/V8 engines that affects FUEL TRIMS and cause engines act like old cars to nag their owners.
@@glasser2819 I have replaced the upstream sensors, as well as the downstream O². Bank two functions normally, when graphed showing that catalyst is functioning normal ( fluctuating upstream and flat line downstream, within voltage range ), yet, throwing P0230 code, bank one graph is mirrored and throwing P0240. Why is PCM/ECM detecting faults from both banks ?
The only times (2) mine has set a p0420 code in 201,000 milea is after using Lucas fuel system cleaner. Both times the light stayed on for a day or two then went away on it's own...any ideas why this would happen? 2011 ford flex naturally aspirated
Fuel cleaners are designed to help break up deposits in the injectors (if added to the fuel) and carbon build up in the intake and combustion chamber (if feed via vacuum line). They can cause some differences in air/fuel ratio being seen by the sensors and/or cause debris particles (carbon) to pass through the substrate.
My 2010 honda accord v6 is giving me the p0430 code only that code the cats are still new I changed them last year I don't understand why it's giving me this code. All o2 sensors were changed all together.
This code is driving me nuts. It keeps appearing and disappearing. Replaced all the oxygen sensors, and while did that, looked inside the converter using borescope, it looks nice and clean. I have no idea why it is doing that. At idling, the temperature is at 1050⁰F degrees. Is that okay? Something tells me it is not.. also, i do have lower power feeling for the engine. It is sluggish on acceleration. Revs higher than before when i bought it. The mileage is 129k. Cleaned all the injectors. Replaced spark plugs. Cleaned MAF. but it keeps doing the same, check engine light appears and disappears. On an off all the time. Also, I have very little vibrations when sitting in the car. Someone would say it is okay, but i don't think it suppose to do that. Checked it with the launch scan tool and some parts of measurements it was showing as red while others green. When reved the engine it was turning green. Not fully understand those values yet. Just getting into this mechanic things. Maybe bad injection timing? Ugh, no idea!
Basic maintenance sure saved me alot of head aches over the years. My wife said. I love the way your truck idles so smoothly. I just smiled.
I had p0420 code so I changed lambda sensor post-cat and all spark plugs and then after a week the enginge light disappeared ✅
youre gay, no woman ever says that...unless she wears a strapon
This person is a 😢 very professional person, thank you for your advice.
All of these are great tips, but let me tell you my experience. I have a 2013 Nissan Altima S with the 2.5 4 cyl. For several months I was plagued with the P0420 code. My mechanic tried all the usual diagnostic techniques, checking o2 sensors, cleaning the catalytic converter, even going as far as gutting the rear catalytic converter to relieve a suspected blockage. The problem not only persisted, it got worse. Instead of coming on every 150 miles or so, the Check Engine light came back on every 50 miles. I have probably spent around $500 trying to get the stupid light to stay off. You know what finally solved the problem ? As per routine maintenance, I removed and cleaned (I have a K&N) my air filter. I cleaned and re-oiled it according to K&N's instructions and re-installed it. NO MORE CHECK ENGINE LIGHT. After all the hours and all the money needlessly spent, the solution was to clean my freakin' air filter ! Something so basic and elemental, I didn't even think of it. The lesson here ? Check the most basic, cheapest stuff first. You may think you have a special car with a problem so unique, no mechanic has ever seen it before. In all likelihood,
its something simpler than you or your mechanic realize.
Just a heads up if you use a K&N, keep your MAF clean.
EXACT SAME THING happened to my son on his G6. His mechanic told him some cars don’t like the K&N filter.
don't use K&N filters , use oem
Save the K&N for the dirt bikes. Use OEM air filters. I put original OEM air filter in my Lexus LS400 and now I'm getting better gas mileage. Switch to the OEM Air Filter and run a can of 44K Platinum by BG in a full gas tank. That got rid of my Check Engine light.
My CATs have 278,000 miles on them. I always use 44K and it gets rid of my check engine light for quite a while. I use Chevron gas. My emissions test results way below the limit. Codes P0421 or P0420, OEM Denso O2 sensors.. Lexus tried to get me for $4000 for two CATs Ha Ha Ha Bozos
I had a similar problem. But it wasn’t just cleaning the Canon air filter it was also cleaning the mass airflow sensor. The thing that pisses me off is the three mechanics I took the car to when I was having these issues all they didn’t look at codes and replace parts. That’s what they are parts replacers. They have no clue how to diagnose anything on their own without a computer.
Definitely first step is basic maintenance and spark plugs. Then track down all vacuum leaks. After that make sure o2 sensors are good and finally cats as the last resort.
Did all that on my 07 V8 4 runner...down to front exhaust manifolds and cats...
I got this code after changing spark plugs and ignition coils and driving about 50 miles or so. I've done the replacement twice already with no problem. No misfire codes just p0420 efficiency low bank 1. Any ideas?
@@thejagmohan7121 loose plug could cause it. You used the spec denso or ngk plug? If it wants platinum don't use iridium or vs versa. Some motors like the Toyota 3.4 are super sensitive due to the reverse polarity coils. Hard to know your situation based on the general post
@@thejagmohan7121did you scope the O2 sensors?
@@Beast_is_a_dumbass220what does that mean?
After chasing my tail a number of times trying to troubleshoot a P0420/430 DTC, I would check the manufacture’s list of TSBs and see if there were any software/reflashes that might address the issue. Wasn’t unusual that new vehicles had very tight software constraints to get them certified and keep the EPA happy. After the vehicles amassed many miles through a myriad of conditions, updated programming via reflash gave the ECM a bit more elbow room to keep the MIL off. That “Silver Bullet” saved many of my customers the high cost of converter replacement.
signed,
One happily retired 35 year ASE Master Technician…
Could you explain what you said as if we were 5 year olds because what you said went over my head 😅
Edit, reflashing meaning, reprogram the computer
I wish I were your next door neighbor. My 2006 Toyota Sienna runs real smooth and yet I keep getting a po420 and 430 code.
Great info.
@@BobSmith-tn2qp he updates the software like downloading an update from the play store to the engine computer and loosens up the tight restrictions for whats allowed through the catalytic converter and sensors that read from it so it has more wiggle room and wont throw codes
The problem is finding someone that knows something.
Extremely true
The problem is finding someone who is willing to pay someone who knows. 😊
@@rp6236 I would gladly pay someone to check out my truck that knows what they are doing. I want a guy that understands fuel trim’s and all this other high tech garbage. Last guy said 02 censer and that fixed nothing. I would also like someone who knows how to tweak the computer. I haven’t found anyone yet other than part changers. Hell I can do that! I did fix the track control problem. My tires looked good but I you really look closer one was separating. As soon as I pick up speed the one wheel would throw a code. New tires a it never set a code again.
I work at auto zone and seen mechanics send their customers to the store to buy parts while they are guessing
@@rp6236
A really good mechanic will be fast, efficient, and get it right the first time
Glad to see a video about Cats that is informative accurate and all around a good routine for diagnostics.
Bravo.
My take away. Over time it sure pays to live in a state that does'nt have the smog check inspection fraud.
Ugh dealing with this exact problem now. Damn politicians
I’ve been ase cert tech and service manager over 40 years and the only fraud l’ve seen is poor diagnostics and ignorant owners. Most cars and trucks thru the shops l’ve worked have hundreds of thousands of miles with original converters working as designed. Not a perfect system, but the best we have if we want to continue burning fossil fuels. Basic maintenance consistently performed is enough to keep most issues at bay. There will always be exceptions and poor designs and manufacturers.
@@arthursmith1732 So my car is 17 yrs old with clost to 200k miles. The stock cats are no good they have lasted for as long as they could now throwing P0430 and P0431 trouble codes. I'm in California where it is illegal to install EPA cats. Plenty of those availalable but no retailer will sell nor ship EPA cats to Cal. Politicians will only allow approved CARB cats as replacements, none that exist in their database for my vehicle. I spoke with the state emissions rep they said my only option was to junk the car when there is nothing else wrong with it. Many others are going through same issue in my state. I don't see how this is caused by ignorant owners
@@JYAN2852 I knew you were in commiefornia when i saw your first comment! Im also in this ridiculous state and i have been going NUTS trying to get my damn van smogged! Ive scowered the internet looking for the right damn cats and when i finally find some, THEY ARE THOUSANDS OF DOLLARS!!! Thanks a lot gov newscum!! I hate this state cus of that commie bastard! Ive tried cataclean a few times and paint thinner too! Damn light keeps coming on at or before forty miles! Ive put TONS of money into this van and i will be damned if i am gonna scrap it!!
This is only possible in the U.S...in Europe you have to pass this test ..
Hey look for the environment...and for our planet...hahaha
👍
Several years back I followed Scotty Kilmer's advice for a catalyst failure code. Added acetone to a low fuel tank and ran it. The code resolved and never came back.
Thinner to a halve tank and than drive 150 miles was Scotty his tip...
How much acetone did you use?
@@jcmxs4 previous commenter corrected my post, it was laquer thinner (not acetone )to 1/2 tank gas
@@zanetracks6592yes How much lacquer to how many gallons?
@@leslielucci3182search Scotty Kilmer channel
Got the code on my wife's car. They tried to sell me a converter. Then I realized it happened after daughter put gas in the car. So I checked the fuel cap problem solved didn't even have to replace cap.
May God bless everyone!
Me too after paying for a new not quality converter..at 102,000 miles..from q government recommended repair shop ..
I think this is what's going on with my car. Either that or because I got gas from a place I don't normally go to. Came on the next day after I got gas and it seems like my gas cap isn't getting vacuum sealed when I put it on
What is the fuel cap issue?
@leslielucci3182
Somehow, she didn't get a good seal ,nothing wrong with the cap. You're supposed to turn cap until it clicks, then turn, I believe, one more .time.
@@billybarnes9208 the cap to my Subaru is lost because the “string” attached to it broke and when my teenage son took the car on a long camping trip, the cap was forgotten at one of the gas stations upstate NY. So far I haven’t replaced it because car drives fine without it. The 420/430 code existed back when we had the gas cap.
experienced an interesting one in regards of this code P0420…it wasn’t my cat at all but rather it was the oil leak that spread under my car due to negligence oil changed my oil guy did…my Hyundai dealer discovered it and saved me $4K of cat repair costs…it was a breath of fresh air after I learned about it
Yup I've seen that happen. Some cars have oil filters located directly above (or close enough) to the upstream 02 sensor and that oil filter can be in a very restricted spot in which you don't have much of a choice but to make a mess when you remove it. When that happens it's very possible for oil to leak/splash/drip on to the 02 sensor and eventually work it's way through the threads and contaminate the sensor. I've seen this mentioned as a common issue in several car threads to the point that many car owners of that particular make/model started doing their own oil changes so as to not have to deal with the P0420 shortly after each oil change. This is also a perfect example of why it's so very incorrect to assume when a P0420 code pops up that it's the cat. The vast majority of times I've deal with that CEL code, I've been able to resolve it other ways. Only once was it a bad cat and that was within the warranty period (luckily) and it was also quite obvious that it was the cat because it sounded like a metal can full of pebbles sliding around under the car when coming to a stop or accelerating indicated a shattered catalyst. But every other time, it was not actually a dead cat and the resolution was usually relatively simple and a fraction of what it would have cost to replace the cat and/or sensors.
What do you use to clean the oil off? Mine isn't leaking but there is a lot of oil all over that area.
@@jludtxs I didn’t clean it myself but I noticed when I brought it to my mechanic and told them about it…they air pressured hosed it underneath with some water and wherever the leak was coming too from the sides
I bet you're 2qt low of oil every oil change🧐
@@keithburningbush6456 Can you elaborate on that? I'm a backyard but capable student. But I don't follow your tweak there. Are you saying they spilled a lot of oil? or something else? Just wanting to learn.
Wow! I wish my doctor was as knowledgeable, methodical and logical as this auto technician!
Excellent video. Just the tip about the shop vac to find leaks was worth the watch.👍
So by doing that, just spray the soup/water on the hoses and hopefully see a leak?
@@bze06fishinbwai63 Yes, on all the exhaust pipes, and then hoses in the engine compartment.
With direct injection engines it can be the injectors. The code is often accompanied with a cylinder miss code.
Just a heads up, injectors on a direct injection engine are under such tremendous pressure compared to port injection. Injector issues on DI engines can actually cause compression issues. If DI injectors are ever removed for any reason, they must be replaced with a new injector to prevent compression issues.
Another splendid tutorial, Sir i salute you for all the great effort you put into these awesome videos, Thank you and please continue
Diagnosis like described is like watching the carpenters on this old house, it's how things should be done but rarely are.
Cant beat the old blokes
I had this code on my Chevy Cruze LTZ. A fresh set or plugs and a new coil pack solved my issue. 170k miles. It was due for a tube up. $200.00 we’ll spent.
did you notice a black smoke
@@LOLONO666 Only when smoking pot, I guess, LOL
What in the world is a tube up ?? Lol
Do u mean tune up ??
I just got my 1st Autel today. MK808BT. So far I'm loving it. Just changed a bad ABS module and was able to flash it and fix my abs lights in my town and country 3.8. This 0420 code is all I have left and both 02 sensors are new so I'll be checking out the converter. Awesome video. Thanks
I think the point of the video is that just because a code is thrown for a certain component, that component itself might be the singular issue, having lived it’s long life, and time to be replaced, like spark plugs, ignition coils, batteries, brakes. But more often than not, by a large margin, the actual cause is because of another component which is malfunctioning and it’s symptom is causing a reaction in the component that is represented by that code. You could replace that component every month and still not fix the problem.
Can't tell you how much I appreciate you posting this. Your presentation is professional, and instructions thorough and detailed. Unlike other videos with "quick fixes" that are on par with slapping a band-aid on a gunshot wound, you covered what's most important: the root cause(s).
I was able to determine the state of my cat (spoiler: it's failed 😅) before my lunch break was finished.
Thank you again for a fantastic break down. I look forward to your future content!
This was VERY informative. Thank you.
An extraordinarily smart and kind gentleman, he explained the basics and specific things. My Charger's converter was sentenced by "professionals" in the dealership, but it turned my engine was running lean due to wrong calibrations. So, I got my PCM replaced and the P0430 code is gone and not coming back.
My PO 420 code came on due to a Fram extra guard air filter that I had just replaced went back with original equipment Motorcraft air filter in PO 420 code went away, not saying that there’s not some underlying issue but that’s what removed the code on my 2018 Ford F150, 2.7 L.
I just took out the motorcraft air filter and put one of those red STP air filters in. Now I have the code 2 days later. Interesting. By the way I had thought of this possibly being a problem and had already ordered a new motorcraft. The STP FIlter was new when I bought the car but changed it out in a few days to motorcraft.
I definitely will try this. Unfortunately, I was recommended getting a heavier air filter because the 2015 Expedition didn't come with a cabin filter.
I took out the o2 sensor, installed an anti-fowler and reinstalled the sensor. Haven't had an issue for years. LOL.
does this affect economy or performance?
@@Jordanjuggin shouldn't affect either
What’s an anti fowler please?
@@serchizmit is a threaded pipe that threads into the O2 sensor bung and the sensor is threaded into the end of the pipe. This puts the sensor outside of the exhaust stream helping to have a steady O2 reading on the secondary O2 sensor and avoid throwing a code. On some cars this works and some it won't.
Before or after cat?
This is a logical troubleshooting process ... and one I cannot see the typical independent or dealer mechanic spending time on. Two dealership techs independent of each other relied solely on DTC readers -- and incorrectly diagnosed the need to replace both of my 4Runner's cats and related sensors due to severe loss of power. Neither fixed the problem. An independent could not identify the source of the problem, either. Finally, my old-school pre-ECU carbureted background whispred "fuel pump," and I insisted under emergency circumstances that it be replaced even though the dealer tech was very leery. I was right ... but also several thousand dollars lighter in the bank account. Apparently, a bad fuel pump will not send adequate fuel, causing lean codes that seem to DTC readers to be cat-related. The lesson is that typical techs either cannot or will not do the kind of research outlined in this valuable video.
Their is no possible way that I know of for a lean code to be determined as a cat failure. Whoever you took it too either did not know what they were doing or knew exactly what they were doing! Did you receive your old cat back?
@@jeffflanagan2814 No, I did not. Didn't even think to ask. It was a bad situation all-round, but it is fixed now. I the end, I have two new cats with sensors, all new oil-control valves (another misdiagnosis, but they were indeed in poor shape), and a new fuel pump. All this at less than 160k miles, not what one expects with a 4Runner.
@@jeffflanagan2814 exactly
Did you recover any money from the mechanic?
@@stillwaters6198nope but I bet that mechanic sold his old cats to make some $.
That is a brilliant way of troubleshooting exhaust leaks! Beats my way of crawling under the running car and running a bare hand around all sides of the pipe/joints trying to feel a leak...or waving a cigarette around looking for the smoke getting distorted (which, since I switched to e-cigs, is a lot trickier 😃)
Could probably take a big puff and see where the exhaled vapor goes maybe?
@@tehagent1321 Yup, that's what I do now, but it's not a steady stream like a good ol' cancer stick gives ya.
Ditto!
I have an 02' Blazer zr2 4.3ltr. Got a new Cat, Rotor, Coil, ECU, Wires, Plugs, etc.
My Check engine light came on & got the 0420 code. Exhaust is new also. It showed Bank 1 below temp. threshold.
I changed bank 1 02 Sensor & same code came back. I do have another 02 Sensor located on Bank 1 Sensor #2, the 1 just before the new Cat. I'm installing a new 02 Sensor there today.
No leaks, etc. Everything I had installed has less than 400 miles. The Cat is a high flow, Flowmaster Cat & the Mechanic Shop said it wouldn't throw a code. Zero power issues. The Truck is running great even with the light on.. I cant even feel it idling at a red light with the AC on!
Unfortunately, that might not be true about the new cat throwing a code. One reason why a few states require cats certified by CARB. What is the code number that you are dealing with?
I've read several comments and agree there are several different causes. But, for me, the code is for Bank 1. This means that the side of the engine with Cylinder 1 has an issue. Therefore, it does not seem like common components of the engine are at fault - such as a dirty air filter or MAF. It seems more likely that the issue is related to that side of the engine and it's combustion, oil, gas, adn exhaust components. Has anyone had an experience where the code specifies Bank 1 but it was not necessarily fixed by a component related to Bank 1?
My car currently has this problem and I'm just trying to find what parts to fix before I get the cat.
@@YakanAutumn My car has the same, P0420 Catalyst system Efficiency Below Threshold Bank 1. I just saw a video that said to try the Catalyst sensor, so i just bought it and will put it on. Hopefully that will fix that damn ISSUE!!!
@@bze06fishinbwai63 uppdate on How it went.
@@bze06fishinbwai63 did it work?
@@bze06fishinbwai63 we need a update! 😂😭😭
In the North East we most commonly see faulty converters.
Exhaust leaks will show up in the fuel trim data, if theyre affecting the converter.
Exhaust leaks are audible, and traceable in fuel trim data.
95% of the time, its a bad converter BUT the first step is to replace the rear o2 sensor, then the cat if code comes back.
Excellent Video this guy knows about cars . He explained everything very well !!!!!!!
From one old man to another, this car mechanic has aged just right; using his experience to not overprice customers and make sure the origination of the problem is cured, not just the symptom.
Thank you for this video, this is exactly what I was looking for!
In a world of "repair hacks" be the smoking gun, not the pile of bullet casings. I'm glad to see this video on the top of the search.
A P0420 just mean the car has developed a smoking habit
Yeah! mine did 🤣
Have an '04 4Runner V6 4.0L. Had 420-430 and 206; cylinder6 misfire. The #6 plug looked oily- Checked compression 175 psi. No loss of coolant or oil. Good compression. Installed new valve cover gasket set. No more 206 code . Still had 420-430- ran a couple of bottles of cat cleaner & one gallon of lacquer thinner through the engine, per "Scotty". No help there. The 4Runner runs like a banshee. Very quick response. No sluggishness. No foul smoke from the exhaust. No issues with exhaust leaks or vacuum leaks. Changed both downstream sensors & added spacers to the downstream o2 sensors. No more 420-430. Passed smog, then I removed the spacers. Ran good for about 2 weeks before the 420&430 reappeared.
I will reinstall o2 spacers (also known as spark plug anti-fouler); you can buy o2 spacers on line with out having to buy two 2 spark plug anti-foulers per o2 sensor, then having to drill the outboard fouler to accommodate the o2 sensor. Just buy the spacers on line. they are cheap & install easily. They come from China, so may take3-4 weeks to receive, but they can work. no guarantee, but cheap enough fix & often times does work.
If the problem does not go away after I reinstall the spacers, I will buy a pair of new after market cats- For the 4Runner-they are multiple listings on eBay & Amazon. Any reluctance of the seller to ship restricted state (like mine: CA) I tell them it's for my ranch truck, not registered. They will ship it. They want the business~😁😁 There are YT vids on the spacer install and the anti-fouler method. search them out. Some spacers actually have a mini-cat screen in them. Again-they are cheap.
Cheap - yes. But it isn’t a fix, its a bandaid.
YOUR EXPLANATION THE FAILURE OF A CATALYTIC CONVERTER AND WHAT CAUSED IT IS ON POINT AND EXCELLENCE! CHECK AND VERIFY!
My check engine light hasn't turned off in ten + years. I finally gave up on it. I think they exist to get people to empty their wallets on worries that don't exist.
@@user-2Hteyasizyc you sound like a scammer
I've come to the same conclusion, until it effects engine function ignore the pretty lights.
Finally....a REAL teacher who even speaks English that is understandable. There are dozens of these video's here on UA-cam that are pure GIBBERISH....or.... BROKEN ENGLISH as I never understood a word. YOU are a great teacher sir. Thank you.....
Thank you for the compliment! Glad you're enjoying - and learning from - the videos.
I bought 10.00 of gas at Ingles Grocery where I live. Approx 5 minutes later the check engine light came on. I had it checked at Advance Auto and OReilly. Both told me it was the code to replace the catalytic converter. My 08 Prius was running fine so I just kept driving it and the next day the light went off! So maybe the O2 sensor is going bad but don't just run out and buy a cat until you know for sure!
As a "seasoned" auto tech, I have had trouble at times with the P0420/430 codes. Most of the time, it ended up being a bad cat convertor as you can watch the downstream O2 sensor switch as fast as the upstream: This almost always indicates the convertor is bad. I have found air/exhaust leaks to cause it, of course and I have found a similar test: You can use the evap "smoke" tester in the exhaust. This has saved me many times. Also, many aftermarket convertors are made cheaply and not as efficient as the correct factory unit. I've installed these and had the same code reappear. When I finally convince the customer to spring for a factory unit, the problem goes away - Just sayin
I just bought a smoke tester to hang from a branch in my shade tree . I know what I'm doing tomorrow . Thanks .
In my case had more voltage from altenator and make ECU to read false from O2 sensors the car has 240.000km or 148.800 miles , when fixed ( altenator ) P0420 code gone after some miles , without erase from ECU .
I love your videos very knowledgeable! Learn a lot from you sir! My name is TASHA from USA 🇺🇸. My check engine light reads that I need to replace ignition coil and spark plugs as well as a cylinder 4 misfire secondary DTCs, p0420 cat efficiency helper threshold bank 1 and 83-13 ECM/PCM relation failure. I have a Honda Accord 2009 LX. I’ve driven like this 7 years! Now I fear how much repair will cost. Why me? 😩
I love your videos very knowledgeable! Learn a lot from you sir! My name is TASHA from USA 🇺🇸. My check engine light reads P0304 a cylinder 4 misfire secondary DTCs, and P0420 cat efficiency helper threshold bank 1 and 83-13 ECM/PCM relation failure. I have a Honda Accord 2009 LX. I’ve driven like this 7 years! The Engine Light Has Been Solid For 7 Years. Should I be worried? And can I keep driving like this without risking my health?
We had this code and a mobile mechanic was able to use his professional scanner to show the two banks, upstream and downstream measures, etc. It was very helpful to see this info vs. guessing. We got an OEM cat, replaced only 1 cat of the 4 (thanks 4Runner), and no more code.
The P0420 in my car was caused buy a combination of a worn donut gasket at exhaust manifold combined with worn engine mounts. Code would popup when driving up steep hills. Downstream sensor was reading lean. A new gasket and mounts fixed it. Vehicle is a 2006 Toyota Matrix 4WD with 226,000 miles.
Great video and took my anxiety down a notch!
Cristal clear,very useful info,as you say sometimes a cat issue is tricky to confirm .. best video and explanation about cat issues i see...
Keep it up.
Greetings from Spain 👌✔️
Thank you Mr Trainer👍
Im a single woman trying to survive this code..my truck is a 1998 gmc 5.7 sierra truck 2 wh drive..
I must get that Autel thermal imaging cameras. Thanks for the diagnostic tips!
🤣😂🤣
I sprayed down the flex pipe with soapy water and it started to bubble up .I currently have a p0420 code .I’m going to repair the flex pipe and hopefully that will solve my CEL.
Very likely it will. That is letting air in and throwing of what the sensors are seeing and could even cause the cat to overheat because of the leaning out of the feed gasses. Let me know!
hey did you ever fix the flex?
Great explanation covers everything
Thanks for helping
So it's an exhaust leak. That makes alot more sense. I knew there was a Crack, and my tailpipe dropped a bit this last week and now it's running like crap and throwing those codes. Thank God I was already ordering a muffler
I solved the problem. With 210,000 miles, I traded the Altima for a '21 Toyota Camry.
Hahahhahah😂
Looking at the same solution as well, seriously. My new to me '07 Honda Odyssey has become a money pit. I've had a bear of a day and your comment made me laugh, thank you!
Good solve. It only cost 20000
Nissan to Toyota - Solid Chess move!
Excellent. Now you have a new financial liability that depreciates with new unsolved problems. 🤣
Bad CAT... Just check your cars insurance and park it on a busy city corner over night.
The minute mechanics will remove it for free....
😊
That happened to me
Cat cleaner removed the check engine light on my old lexus. But the VSC ON OFF lights still on (which go on in Toyotas when the check engine light goes on). Any ideas?
In my experience most of the time I’ve seen these codes it did end up being a bad cat but I have saved my customers a lot of money on occasions where it ended up being something else
You haven't gone far down the rabbit hole of OBD diagnostics.
I'm sure you find bad Cats BUT that's not what his message is.
Like the Trainer has said "Cats are built for a lifetime. It may go bad, do you just replace parts or find out why it went bad to fix the problem."
I'm putting my money on the fact that a Technician finds what has caused it to go bad. Any takers?
Trust the code, check the circuit ,
Make the repair.
It's always something else. Parts seldom just go bad. There is a cause for everything.
@@christopherfoxwallace1291 💯 agree with you on this but this code is a hard one to crack due to the amount of inputs that can trigger it. I have tried multiple times to get rid of it even with a good cat and had to try various things to get it remove.
It looks like getting the job done right.
@@christopherfoxwallace1291
I've replaced the (2) converters on a 99 4runner 4 times in 3 years. I gave up after 3 sets in the first 4 months i had it. Nearly one thousand into diag else where the last 2 years and no luck. I take it in specifically asking for why its damaging the cats and they come back with "replace them." Or my favorite "P0420 is always a converter failure." I pay the diag and onto the next shop. As much as I don't want to pay because my question goes unanswered, they still worked on it so I respect that. I gave the first shop that replaced them a second chance and they installed their best cats yesterday. 4 hours later it was back...in for a diag next week. Fun times.
Thank you so very for explaining this. I'll get a P0420 error, then it will disappear for weeks or months. My 2k Dodge Dakota has 2 O2 sensors.
My Nissan nv200 started to doing it as well it goes on and off already pass smog
Carbon buildup can also trigger Code P0420. My 2014 Jeep Grand Cherokee Laredo threw up the code even tho the o2 sensors and cats were good. So I thought hmmm what if it's carbon buildup? Got 2 cans of Seafoam intake cleaner, followed directions and after it blew all the carbon out the check engine light shut off and P0420 was gone forever
being a 00s chrylser guy (with several in my fleet), i'm very familiar with the O2 sensor outputs and their readings on my Autel MS 906Pro. However a friend of mine had the "dreaded" P0420 code pop up on her Honda. The software on the Autel doesn't report Honda's sensors (2013 Odyssey) in the same way, so I was struggling to help her diagnose, is it a bad cat or a sensor problem. Curiously, the MIL went out on its own, and the code was stored as permanent, but not active. In fact, I had to use EOBD to read both sensors, with the downstream in V and the upstream in mA. My educated guess is she has a bad upstream sensor, and not a bad cat. I came to that determination based on comparing the upstream data between both banks, and noted that bank 1 would occasionally be "smoother" than bank 2, instead of roughly tracking the same, and even once go completely flat line at 0 mA. I considered a possible wiring fault, but the fact the traces look like a sensor getting "lazy" or "falling asleep slowly" then suddenly "waking up", makes me lean towards a failing sensor rather than a wiring issue. The downstream sensors would also follow the upstreams in their reporting and graphing.
Where would a DIY shade tree home owner mechanic go do to find more information about specific vehicles and their expected O2 sensor outputs and performance.
Can a bad purge valve cause this? My journey has power and is very responsive, it also has the code for a bad purge valve.
My P0430 code has become intermittent. Today was cool outside and tonight the temperature is 45 degrees outside. And the code on my dash went off. I just replaced my O2 sensor 2 weeks ago and it seemed to work because there was no engine code. Then 2 days ago the light came on and now tonight the check engine light was off again.
Pete, if you can help ....
@5:24 the the AFS stream 1 graph seems behaving normal and lower stream graph is at constant zero....is it due to narrowband sensor has not achieved required temperature to give its output???
My 2018 Dodge Journey has the code and
Drives sluggish…it always seemed to have since I got it new in 2019. I changed the nasty engine filter.
Anyways, this video was helpful in understanding the mechanism of the CC and the code. So begins the “journey “…🤣
Most likely the upstream sensors on a late model chrystler. Had it many times
What did it end up being?
Have the p0420 code on our 2012 honda pilot. Started bogging when trying to accelerate. My 1st guess was bad cat. I was hoping a bad 02 sensor or air filter but with it running crappy im quite positive its the cat. Which really sucks
Reason #197 why I love Texas, I drive a 91 bmw e30 325is and all I need is a safety inspection so no cat converter is needed to pass inspections 🥳🥳🙏
My experience with p0420 is usually a ignition issue or an exhaust leak at the manifold. There are other possibilities but in GM platforms it's more common to have high mileage plugs or worn / lose exhaust pipe to manifold seals.
I have an small crack in my exhaust manifold. Jeep xj. Code just happened after a new ECU was installed...
Probably not the cause but my ‘98 Corolla was less than a year old-still at the Dealership Service stage-when someone forgot to re-fill the oil tank after a change. My mechanic kindly rebuilt the engine and the code began soon after.
@@cruz7073Did the new catalytic converter fix the problem? Having the same issue on a 2001 Accord lx.
@@Nomenclatureishexhaust leak is pretty common. Esp if the engine was recently installed.
@@cruz7073 this is what Toyota says is the cause of ours, too. Supposed to be common in this model. Sometimes tightening the gas cap will help.
Helpful information! I have the Autel AL519 which told me I had an issue on Bank 2. I deleted the code after checking the front & rear temperatures, as the drivers side seemed to have a wider difference between the two (which I believe is bank 1) as I have 2 converters on my F150 pickup. Interestingly, it's been a week, and after having the initial code come up, it has stayed off, although I will test again today. Thus makes me wonder if it was a random code that popped up for some reason? Nonetheless, it's something I'll be keeping an eye on. Thanks for the video! Having 137K on the truck, I would imagine the converters 'may' be getting to the end of life, but I'll continue to watch for check engine lights. Fuel mileage hasn't really changed either.
Thank you I learned a lot today while watching this video thank you
This was very thorough
Good video he an expert knows what he's talking about
07 jeep jk 3.8 air temp intake senor was bad took out passenger side converter. Never threw code about sensor. Also had rad fluid leak on o2 sensor caused 420 code
My CEL light shut off on it's own after one day. Freeze frame data from when the code set reported my RPM at 3950 in a low gear. I did recently get distracted and forgot to shift (manual trans). I would have thought the PCM would ignore that. I will do the other checks in the video just in case.
You FORGOT to shift? Really? I've only ever driven manual transmission vehicles and shifting is automatic (no pun intended!). It's about muscle memory, not just remembering to shift.
On a 2006 ford crown Victoria police interceptor I have a PO420 code catalyst below threshold. I smell an exhaust leak, and per the scan tool one sensor is dead, and cat has reached 1650 degrees. Would you say that was enough to damage the cat beyond saving? And I'm taking it the leak gave too much air, this too much temperature? Pleeeeaaaase help! I know you kind of answered my question in the video
Take care of what you definitely know is bad, clear the code and rerun the monitor. It is possible that the cat overheated but the only way to know for sure is to take it off and look through it OR use a thermal imaging camera to look for signs of melted substrate.
Yes, air leaks are like excess fuel - either causes the cat to run hot.
thanks for the great explanation ...
there MUST be a better way ...
amazing engineering to make a car a car ...
but it's WAY too complicated ...
and expensive ...
What is the average lifespan of a cat? Thanks for the video.
200k -300k
I got the check engine light with Po420 code but every time I drive 45min-1 hour on the highway the check engine light goes away for a day or two then come back on?
O2 downstream sensor has been bad in my 2010 Camaro for a while now. Now I'm throwing these codes. Barely made it to work. Ugh.
How did you fix it?
Also look for factory TSBs. Could be software issue. Some aftermarket cats aren't loaded correctly which can lead to a comeback or cat monitor to fail.
Also, should I run some heat through the truck because I have been running crappy gas for economy and this problem started after the outside Temps reached -15 and it wouldn't start. I "think" it's the exhaust leak, but water in the motor that froze probably added to the issue
mines came on after getting a oil change, what could the problem be?
A bottle of Cataclean cleared my P0430 code on my wifes 2012 Jeep Grand Cherokee.
Used it way too often for 3 years, then tried Lucas, & no ck engine light for 9 months.
I have a 2008 infiniti Ex35 which had the P0420 code.
Was diagnosed that the cat's needed to be replaced, as appeared to be clogged. Replaced cat's.
However, I now have extremely, poor gas mileage.
There are no error codes.
Any idea what is wrong? I am so confused that the cat's were replaced and now my fuel use is up by 30%.
Witch Aurelia scanner will sync a cam sensor to the crank in a 2000 jeep 4L straight 6 when the ecm does not support sync
I have the code thing.
But an expert said he could fix it for under$220.
So then I'm thinking that it could be the O2 sensor because my mileage is about 178k and they might go out around 150k or sooner.
I saw one for about$170 and the guy said he could fix the problem for $220 so I think maybe that's what he was going to do.
I hope that's the problem then I could just do it myself.
Be careful - without performing a proper diagnosis, no one can tell you what they can do to fix it. With the mileage on your engine, it could be a number of possible causes, including the converter. Seek out a more professional diagnostician.
Long Term is the window of time the adaptive memory dictates the fuel trim, Short Term is live data calculating to learn the parameters for the adaptive memory to update the Long Term. The O2 sensor signals rich below .45 volts & lean above .45. The Engine Controller only cares about that threshold & uses that to determine fuel trim. .. in other words the computer calculates the % of time that the O2 sensor is past the threshold of .45 volts & does that each time the threshold is crossed.
that’s the most intelligent description of some of the many, maaanyy, sorry gramr - thats SUUUUUPPPPEEERR DUUUUPEER mind boggleingly many deferent causes of the dreaded p420☹️.. makes me want to go to a mechanic, except most of them probley don’t have those tools✋(& if I asked they’d probley just say ‘whooos the mechanic here?.. hmmnn - don’t worry about it weeeve got it covered’) which means probley no .
I had my engine replaced. Three days later, the engine light turned on. They checked it twice and they said catalytic converter needs to be replaced. I was told it might came from the bad engine and ruin the cat. It costs a lot to fix it. I used cataclean and the engine light turned off for 3 days but came back on again. They trying to charge me 3500 for it. I can't afford it. Trying to figure out where to take it for a cheaper price
Any success? Cataclean, 1 gal lacquer thinner, Gumout with PEA, point is to clean out cat. Sometimes you have to clean it 2 or 3 times. Then I would clean it replace O2 sensors.
2011 Camry le all stock n 390k miles all original parts. Could not go up a hill but flat driving ok. Seems to lack HP too. Never change trannie fluid, so I'm I'm getting code for torque converter n code for shift selinoid. Non of this has to do with emission right? Check light on n off n p0420 for cat was another code. With these Toyotas, the manufacturer messed up as it is known to lose oil. The pcv needs to be replaced to solve this. Since it is leaking oil but not dripping on the ground, the oil goes to the exhaust n can clog the cat. I had a smog ran with co2 being 0 but hc was 15 so it failed emissions.
Now getting a new cat would not solve the problem. Maybe I'll pass smog upon getting a new cat n can drive for 2 more years b4 I'm up for another smog. Eventually the new cat will get clog up as well so he's right when he said that the underlying issue needs to be addressed first. Plus with mine at 390k miles, maybe it is time for a new cat or get a newer car. Over 2 Grand just to get a cat replacement with mine. Fixing cost more than the value of the car so why bother? An option is to get cataclean bottle as it may help with the carbon build up n hoping to get that smog pass. California I tell ya. If this was MN where no smog is needed, I can go as high as 600k with this gifted vehicle.
Oh n another way to test to see if your cat is good or not is to get a heated thermal laser scanner. You take the reading of the top of the cat, the middle, n the back end. Top should be hot, middle hottest n the back should be cooler. If the Front is the hottest then you have a clogged cat as heat has no way to get out from the backend so it travels to the front n that can do damage to whatever parts there are on the front like header n pump n whatnot to give you an overheating vehicle too.
Very helpful video. Thank you!
I do all of my regular maintenance but got the P0420 code after refilling my gas tank. Thought it was the gas cap, so replaced that. Cleared the code. It came on again several hundred miles after I got low on gas again. I cleared it again. Drove around for a while, checked and even passed emissions. Then 3 days after emissions passed, low tank of gas and code came back on. What is the deal here? My car runs great btw.
Many monitors will not run when the fuel level gets too low. I'm wondering if that is impacting your issue. What is the year/make/model/engine of the vehicle?
If you replace a bad computer, should I reflash the new computer to clear the 420 code when everything else has been done?
The code should not set in the replacement ECM unless the fault still exists. Be careful condemning a computer - they are rarely at fault.
Good day thank you for your help
I need to ask you some explanation about a car that have no problems but don't have a power enough to climb up the street .thank you
If it has no power than it has a problem. Any work done recently? Have you tried dropping the exhaust ahead of the catalytic converter to see if power is restored? What tests have you done?
O2 sensors are recommended to be replaced 100,000 MI. By the dealer and the manufacturer and the mechanic. You can look use some of the cheap scanners that can show you a live data. Of the O2 sensor
hello, just found this video and was reading through the comments. I have a 2004 Toyota Sequoia and I had my 02 Sensor replaced few months ago and the catalytic converted (bank 2) replaced few months ago [aftermarket one]. The check engine and VSC alerts popped up again this week. Took it back to my local mechanic. He think it has to be a Catalytic converter from the dealer so he said he would check with them on the price and get back to me. He says its okay for me to drive in the meantime. For the solution can in your video, what brand do you recommend for my vehicle? 2004 Toyota Sequoia. thanks in advance
Hey, I have a 2012 kia soul 1.6 standard transmission. I've been having the same code popping up after each part replaced. So far we've replaced the knock sensor, the MAP sensor, all four spark plugs, the upstream and down stream 02, and the p0420 and p0420 p, keeps coming back. I hate to guess but I'm thinking the Cat may need to be replaced? Not sure what to do. Any thoughts?
Will aftermarket catalic
Be a cause for p0 420 code
I have a 2012 bmw 135i and can’t pass smogg it actually had a aftermarket air cleaner aswell
Im putting and buying oem parts and see if that will help
Any suggestions?
Sorry for the late reply. Look for a cat that is CARB certified. NY and CA require these to be used as replacements. "Universal" cats won't do the trick.
My 2009 traverse has the code P0430 but it passed the emission test. But I can not find what is wrong with it.
I would recommend you clear the code and see if it resets.
@@MotorAgeMagazine I've done that like 3 times and always comes back. I just got it yesterday and today it dissapeared by itself.
@@elkuartostudio Have you checked for any OE Technical Service Bulletins related to the code?
I got some strange readings on for my p0420 sensor. The cat gets a green check mark and the 02S does as well but the EVAP isn't hitting the mark. Trying to get this car smog ready and out of Non Op but this is the wall I'm hitting. Changing spark plugs tomorrow but idk if it'll help.
I think you are referring to the monitor status for the various systems. The EVAP monitor can be the hardest to set. What kind of vehicle is it and are there any codes?
My 9 month old after market converter was rattling like a stone was in it. (No codes). My mechanic said he could not check any readings because he said back pressure was present. When I asked what the back pressure showed he had no data. Just said he could hear it leaking. He said looking at engine data was useless due to the back pressure and said the cat is obviously broken so he would not be able to test until a new free flowing cat was installed. I basically paid 200 for a diagnostic that he did not do and said he couldn’t do. Is this even right? I feel like I got swindled. I did my own fuel trim readings and my long term fuel trim was around -3.6 on a 20 year old car. That does not me seem bad enough to create a failing car so fast. He also claimed he could hear material down stream rattling around the resonator but I took apart and it’s completely free of material. Doing a pressure test later today before and after the cat. Going to be pissed if I find no issues. I get the catalyst may have broken. I can hear it in the cat when I hit with a rubber mallet. But that’s not what I paid him to figure out.
First thing to ask yourself is, "Did my battery go dead or did I replace it?" Sometimes you have to perform a "Drive Cycle" specifically for your car so your computer can run a "Readiness Test."
What do you mean by drive cycle? Our battery went dead over winter. Its been recharged but the truck will only turn over, not start. 2015 GMC Diesel.
@@kariniemannfuss9208 You are a prime candidate. Just Google " Drive Cycle" for you vehicle. You could get one from GMC or your mechanic.
On my Tahoe I had to let it idle at a specific RPM for a period of time from a cold start with a number of electrical items turned on and drive it a certain way to allow the computer to scan all sensors to know that everything was working properly. The codes switched off and I was able to get the emissions checked.
As far as the no start, you'd have to check with diesel forums with your specific issues. Sounds like a computer communication problem. With no power for an extended period of time, the computer might need to be reprogrammed.
If you install those Sensor Thread Adapters to get the O2 sensors out of the exhaust stream, will that tell the computer that the mixture is too lean and enrichen it causing lower fuel mileage?
We’re talking catalyst monitors aka down stream oxygen sensors, not the upstream sensors.
@@harrybalsonya5619 Downstream.
Car threw a P0420, I installed a known good catalytic converter ( at least it was good on my old taurus, no codes, before giving car away ), car threw P0420 and P0430. Checked exhaust for leaks, found flex band mesh was deteriorated but rippled metal pipe inside was intact. Replaced O² sensors and spark plugs, checked for coolant leaks, checked coolant temp sensor. OBDII scanner shows catalytic converter passed and green, but evap monitor flashing red and check engine light in on. Where do I go from here ?
What DTCs are stored now?
@@MotorAgeMagazine thank you for responding so quickly !
P0420 and P0430
My scan tool shows that cat has passed and is green, but evap has not passed and is flashing red ?
@@MotorAgeMagazine i also graphed live data and bank 2 is normal fluctuating upstream and flat lining downstream, but bank one upstream and downstream are mirroring each other.
@@paulpurdue5963 beware that it takes a couple driving cycles to complete the MONITORS after an ECU reset.
If you have over 90+kMi REPLACE the 02/Lambda UPSTREAM SENSORS as they get lazy yet without a DTC code for failure.
These tired lazy sensors cause vibrations in V6/V8 engines that affects FUEL TRIMS and cause engines act like old cars to nag their owners.
@@glasser2819 I have replaced the upstream sensors, as well as the downstream O². Bank two functions normally, when graphed showing that catalyst is functioning normal ( fluctuating upstream and flat line downstream, within voltage range ), yet, throwing P0230 code, bank one graph is mirrored and throwing P0240.
Why is PCM/ECM detecting faults from both banks ?
The only times (2) mine has set a p0420 code in 201,000 milea is after using Lucas fuel system cleaner. Both times the light stayed on for a day or two then went away on it's own...any ideas why this would happen? 2011 ford flex naturally aspirated
Fuel cleaners are designed to help break up deposits in the injectors (if added to the fuel) and carbon build up in the intake and combustion chamber (if feed via vacuum line). They can cause some differences in air/fuel ratio being seen by the sensors and/or cause debris particles (carbon) to pass through the substrate.
@@MotorAgeMagazine would you recommend that I don't use them anymore? Do you think it might be causing more harm than good?
@@netflooder263 No, I think you'll be fine. Better to keep the system clean on a routine basis.
@@MotorAgeMagazine ok, thank you very much for answering.
My 2010 honda accord v6 is giving me the p0430 code only that code the cats are still new I changed them last year I don't understand why it's giving me this code. All o2 sensors were changed all together.
This code is driving me nuts. It keeps appearing and disappearing. Replaced all the oxygen sensors, and while did that, looked inside the converter using borescope, it looks nice and clean. I have no idea why it is doing that. At idling, the temperature is at 1050⁰F degrees. Is that okay? Something tells me it is not.. also, i do have lower power feeling for the engine. It is sluggish on acceleration. Revs higher than before when i bought it. The mileage is 129k. Cleaned all the injectors. Replaced spark plugs. Cleaned MAF. but it keeps doing the same, check engine light appears and disappears. On an off all the time. Also, I have very little vibrations when sitting in the car. Someone would say it is okay, but i don't think it suppose to do that. Checked it with the launch scan tool and some parts of measurements it was showing as red while others green. When reved the engine it was turning green. Not fully understand those values yet. Just getting into this mechanic things. Maybe bad injection timing? Ugh, no idea!
Thank you, video was great!