P026D FIX! L5P

[@steveostrowski7698]

Thank you! Sensor was completely clogged with soot.

[@chadkelley5523]

Thanks for the video and part number! This code just popped up today on my GMC 2018 HD2500 6.6L so I'll give this a try.

[@jeremiejohnson8614]

Did it fix it?

[@chadkelley5523]

It did but now 7 months later same code back. Going to pull Map it and see what it looks like.

[@user-yh2og4xb9y]

Changed Map, frp, 2 NOX and O2. CEL and Engine Reduced Power mode. Even while sitting and idling?

[@danieldelgado3008]

As per GM technical assistance this code sets from injectors overfueling during deceleration and the fix is to replace all the injectors

[@truckerman9836]

Berryman and seafoam clean them great clean mine every 3rd oil change, 2021 l5p delete on the way soon I hope.

[@kingtut70546]

I have a 2018 Chevy Silverado 2500hd duramax diesel with the same code. Took it to the dealer 2 weeks ago. They said it was a wire unplugged. The truck never ran bad or sluggish. Check engine light came back on 3 day's ago. I took to my local part house to get the light checked out and it says replace nitrogen oxide ( NOx ) sensor with a P026D code. Truck is mostly driven on weekends or my off day's. 104,086 miles on it. Any help is greatly appreciated.

[@AdventureMan-kx3dr]

Disconnecting battery does not work with the L5p trucks they have a battery pack that stays charged to make sure truck has gps capability at 100% of the time even if the main 2 batteries die

[@jflester5863]

What’s the reset called on snap on scanner? BARO reset, BPP reset? I don’t see anything that says MAP or intake air pressure. Thanks

[@glee181]

Count your blessings that this was an inexpensive fix. The P026D is, as the document suggests, multi-faceted. I've changed the air filter, replaced the MAF and the TMAP sensors and did the fuel line flush procedure. Next, will be an inspection of the connector on the fuel pressure sensor (located behind the throttle body) for corrosion (a separate TSB). Thus far, I continue to get the P026D error and occasionally, it does go "permanent" and set the CEL. Injector balance rates are well within spec (granted, balance rates do NOT give you the entire story). Air leaks in the CAC system or a NOx sensor #1 are about all that is left.

[@jaycastillo9313]

I recently had a CAC flexible hose on the passenger side leaking. Worth a look. If you have access to a smoke machine that would help as well

[@glee181]

@@jaycastillo9313 Interestingly, without running a leak test, I've noted small droplets of oil on the bottom of my cold side pipe, "at the CAC connection". I'm guessing there is some leakage, but not enough to send a DTC for out of range condition. Talc power may suffice for power test....?

[@jaycastillo9313]

@@glee181 yes that’s how this started. The actual material of the pipe started to degrade. It was peeling apart and oil leaking from the hose itself not the connection. It might be able to be picked up monitoring the ALER but I never checked that vehicle

[@SteelFlex-bf5ff]

Did this get rid of the code altogether? I had to get my NOx Sensors replaced according to GM

[@blaine946]

Hey bud. Here for desperate help. 2020 denali began rough idling. Wouldnt rev past 1200 rpm. Been to 2 dealers and so far at the 2nd for 3 weeks with no diagnosis with gm support. Truck had a fuel control module and fuel pump replaced. Still
No start. Any ideas? I am a technician myself for the USCG, and this is absolutely killing me being a duramax guru and not being hands on. I am stressed out to the max. Any help is appreciated. Truck is at copeland chevy in MA

[@alexjramirez2]

I had a similar problem. Was the cold side boost tube that came off the intercooler.

[@mondo9.2.5]

lemon ?

[@willspoint88]

I just replaced mine tonight with this part number. When I pulled the old one off, it had a different part number 12670600. After researching, they both show to fit my 17 L5P. Thoughts?

[@jaycastillo9313]

Yeah, part numbers change like you change your underwear. You can check again in a year and the one you just put on might charge numbers. You can see parts superseded to a new number many many times over. Doesn’t mean the pet changed, usually just the number.

[@acelassiter9747]

thanks for the video , my question is why is there excessive soot in the intake ?

[@Shitboxo]

From the egr, recirculating exhaust gasses back through the intake little oil mix from the ccv pulling through the same system makes a nice black oily sooty sludge mix

[@duffmeister6480]

Hi Jay, my PO26D code says injection quantity too high ? , 54,000 miles on my 2.8 duramax canyon. my mechanic thinks there’s an injector problem, and having trouble diagnosing it. Any suggestions ? Thanks.

[@jaycastillo9313]

Yes, I think at this point GM is recommending injector replacement. They say ALL injectors but I’ve been doing the ones that set DTCs.

[@duffmeister6480]

@@jaycastillo9313 thanks very much for such a quick response, but what’s a DTC ? Thanks

[@jaycastillo9313]

@@duffmeister6480 diagnostic trouble code. Just a code sorry for the confusion.

[@duffmeister3373]

Hi Jay. My local gmc dealer service wants to replace my wire harness related to the fuel pump pressure sender. Based on TSB 20-NA-197 that recommends changing the connector, it could cause DTC P026D injection quantity too high. And it’s not covered under warranty. The bulletin says 1 hour, they want 2 hours @ $200 plus the part. Shouldn’t they provide visual and technical proof of damage or corrosion to validate this repair ? 2019 Canyon 2.8 Duramax. Thanks very much for your assistance.

[@lifeofmike5126]

I'm fighting this same cod replaced sensor still have a check engine light

[@jaycastillo9313]

What code do you have Mike? Let’s see if we can figure something out

[@817aqqtown]

Yeah I replaced it it worked but right after I pulled trailer again it popped up po420D

[@817aqqtown]

Po26d

[@jlo2475]

What scanner do you use for the new l5p’s

[@jaycastillo9313]

I have the GM MDI 1 & 2 at work but at home I use HP Tuners MPVI2.

[@jlo2475]

Does the HP tuner allow you to clear the emissions system warning that only gives you 175 mile until 65mph reduced speed?

[@jaycastillo9313]

@@jlo2475 I’m not 100% sure. I would imagine so but haven’t checked .

[@mondo9.2.5]

banks idash

[@chadkelley5523]

Hi Jay, My map sensor didn't come off so great the second time I tried to uninstall it. After messing with it I grabbed it with some pliers and was wiggling it loose when the plastic to the harness broke. I've looked all over the internet and I can't locate the part or part number for the connector that snaps back into the Map sensor. I installed the S&B spacer and managed to connect the wiring back, but for long term I'd like to replace the male connector. Any chance someone can find the part number that has access to GM parts. Truck is GMC 2018 HD2500 6.6 Duramax.

[@jaycastillo9313]

Good morning, Chad. The number I pull up for the service connector is 13587299. Hope this helps!

[@chadkelley5523]

@@jaycastillo9313 Thank so much for the info! That looks like it's it! For some reason the second time pulling it off didn't come off.... FYI, I just found a forum people had same issue and they said make sure the truck has been running and warm. That will help if it's stuck.

[@chadkelley5523]

I replaced the Map sensor and added S&B spacer after about 2 days CEL came Back on. I then added injector cleaner, also added can sea foam , pulled K&N air filter and cleaned it, it didn’t look too dirty, but did it anyways, also replaced fuel filter that was at 50% life. I then deleted All the codes again. After 4 days CEL has not come back on. I hope this was the fix. Again, just the map sensor and spacer didn’t do the trick. Not sure which one did it, but doesn’t hurt to all of them….

[@chadkelley5523]

Well the damn CEL came back on today!!

[@Emin70]

Hi Jay, thank you for the video. I am an owner of 2021 1500 Duramax, purchased it a year ago. A month and a half ago I had my first check engine, took to a dealer they told me it is a Nox censor (dealer replaced it). Week later light is back on. Took it back to same dealer. This time they tell me, it's my fault, that I put Biodiesel in it and contaminated the fuel system. Now they are asking me to pay them $1100 to flush the system and clean the fuel tank, (the truck is still under warranty). My friend has a code scanner, when we ran it these two codes came up P026D and P1089. I stopped using Biodiesel, replaced fuel filter, used additive "Hot Shot's Secret" and reset the check engine light (only lasted 150 mil.) light is back. Tomorrow taking to another dealer. Any advise? Anybody?

[@chadkelley5523]

Any fix?? This damn code won't go away and I have 92,000 miles on my 6.6 duramax..

[@Emin70]

@@chadkelley5523 yes, took it to a different dealership. They run the diagnostics, said they are 90% sure that the problem is in the ignition module. Took them almost 3 weeks to fix it. Got the truck yesterday, drove 100 miles, so far so good 👍.
Hopefully that helps.

[@B-rad303]

Get the S&B spacer kit

[@jaycastillo9313]

Yes! Agreed.

[@RamSingh-td5by]

Hi