ABS Module No Communication (2001 VW Passat 1.8T)
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- Опубліковано 2 лют 2018
- The testing methods shown in this video can be used in any no communication condition.
In this video we are working on a 2001 Volkswagen Passat. The engine is a 1.8 turbo. the customer complaint is a solid/flashing ABS and Brake light. Using the factory scantool Odis we find that there is no communication with the abs module. I hope you guys enjoy this video and thanks for watching. - Авто та транспорт
Same thing on a 2002 Passat. ABS light on constantly and red brake light intermittent and three beeps. Have done a lot of research on this issue. First proceed from the easiest to the more complex checks. 1- Enough brake fluid. 2- Check voltage and continuity in brake fluid reservoir sensor (clean it). 3- Check all the fuses related to ABS (replace accordingly). 3A- Verify your battery delivers the right voltage to the ABS/brake system (more than 12.4v ignition off), clean ground connectors. 4- Scan or have your car scanned with a Vagcom unit or any device capable of ABS reading (if a message of "no communication appears" bad news, abs module is kaput or wiring issue). 5- Clean and check ABS sensors in each wheel (use a voltmeter) also check wiring continuity. 6- Inspect the tone wheel teeth (sometimes there's dirt, rust or a significant wear; clean/replace). 7- Remove and check ABS electronic module. There's no need to detach the hydraulic side (no fluid mess). Inspect the wiring and connectors.
After my extensive search and talking to different specialised technicians, one of them from Bosch, told me these parts are programmed to fail at due time. Meaning you have to replace them yes or yes. A new unit for my car is around $1,200 usd. You can look for a second-hand unit at a junk-yard (around $300 usd). If so, you will need the old one so they can do the proper coding after replacement. Without coding its the same as if you did nothing; you will then need to take your car to a Vagcom equipped repair shop and may even come with the hydraulic unit as a whole, so full brake service here.
This happens no matter which brand of electronic module or car manufacturer you own.
*Note: There are some specialised service centres in the U.S. where they rebuild your module. You just remove the part from your car and send it over to them. Google it and some centres may appear. Some people have found some very fine wires (thinner than human hair) detach inside due to vibration. The inside is covered by a special gel so it is almost impossible to repair it yourself, besides being a highly specialised welding process of two different metals. I have known some people tried the help of jewellers to repair micro-cracks and use their expertise in metal micro-welding. It's a shot in the dark.
For security sake you'll be better off with a new one (if you can find the part), rebuild your current module or buy a second-hand one.
Some folks will tell you if you can't drive without ABS, probably you shouldn't have a car at all! Truth is we have to go through vehicle inspections and our life is on the line, specially on wet and icy roads.
Not all of us can be a Raikkonen or a Hamilton 🏎
Be safe.
Hello I'm an ex quality control BMW Mercedes technician from the '80s '90s no longer involved and car repair at that level my 2002 Volkswagen Golf manual transmission is undergoing some symptoms brake light beeping ABS lights been on for a while a real Christmas tree there suddenly my EPC light came on after having the resonator removed don't know why they removed the resonator it was just knocking underneath the frame I wanted the repair shop to bend it I don't know if him not grounding that part of the job but I don't think that was the issue at this time I think it's just time for some ABS work I cleaned the sensors replace the two front sensors clean the rear sensors car still will not run drove it home and limp mode where it sits thank you for your information
Modules, modules, you're getting them left and right! Well done and thanks!
Well done!! That's diagnosing without skipping steps and really helps me and others properly use test lights (for both polarities) and multi meters! Can't wait to use those methods tomorrow on my Passat with the same issue of no comms to the ABS. Many thanks!
Thanks for bringing us along Tom. I do enjoy the PICO scope addition, thanks.
GREAT VIDEO straight to the point just the way it needs to be , please keep them coming and thank you very much .
Another good video from Positive Lead Diagnostics! Well done Tom! 👍
Good, quick diagnosis.
Tough pulling the trigger on a module like that, without thinking you might have missed something.
Nicely done. I know it takes a few minutes to scope the bus, but a tradesman knows his tools, and the only way to do that is to use them regularly.
Nice video Tommy. I also liked the Pico bonus 😉
Thanks for the video! liked the Pico hook up at the end. Not necessary but good to see.
Great content...again something that initialy looks complicated is sorted with a logical aproach
Thank you Tommy. Good job. Your doing great. Really appreciate you.
Great work. Nice simple tests with the test light
Excelent video.i like the way he explanation. Simple and effective. Few of this videos ..thanks man well done
Nice!!! Love these videos.
Well done and very informative young man.
High quality diagnosis!
Superb young man a very good video on this unit, Thank You
Excellent job, thanks for sharing.
So the ABS module lasted 17 years, I'm impressed!
Thank you for interesting videos. Keep it up! /David, Sweden
great video very professional and well organized.
Good diagnosis big thumbs up 👍
FWIW its either a shorted Data/signal line Choke or a fried CAN SMD chip that is responsible for hand-shacking between the ABS MCU and the rest of the system MCUs, i will lean towards the 2nd guess its just a common failure on theses units
Good job Tom keep it up
Awesome video!
Amazing video thank you.
So, i had the same issue with a newer vag model,2010 seat leon.
As soon as the cold season hit, abs started acting up.
I pulled out a full module(pump included) from a scirocco (same part number).
The car worked fine until the next cold season began. Same problem.
Can anyone help? Did the customer owning the car ever come back?
Excellent job
I got a 2006 Touareg with a 4wd module not communicating. Powers + grounds to it are ok. Resistance at ecu pins 58+60 is about 60 ohms. Alldata says resistance should be 120 ohms. Do you think the ecu is bad? I got 12 other modules not communicating as well.
real pro, great help, thanks
Thanks Tom for share ☺
great video thanks a lot
Hi Tom, finally you get a chance to call the ABS module, but I have a question: for an ECM, when powers and grounds are OK, but no comm., there is also possibility of a shorted 5V ref. line. Is this also possible with the ABS module, does it feed any sensors, relays, solenoids, etc. via a current-limited supply? Can this be seen from the wiring diagram/notes? Thank you!
Good video, if I’m not getting a reading on the two ground pins, any ideas where these two wires trace back to?
Seeing fewer and fewer of these issues with these cars... were also seeing fewer and fewer of these cars. =)
nice video!! for a brief moment i tought you had the same issue as i... i dont have power to pin 15 , but i also dont have any blew fuse. strange
Mu abs light is on but i did diagnose no codes check all wires so i assume module dead??
LO MAXIMO MI AMIGO
Thanks man, this was a great and instructive vid. Looks like the same absmodule as in my sons Impreza, GD9 2002, also a Bosch.....question: were do you find your wiring-diagrams?
I am not able to communicate with dashboard and central electrics cluster in my audi a4 b7. I tried both with VCDS and Obd eleven both threw communication error. any tips on where to check?
Hello sir Iam having problem with bmw 325i no comm to abs module any advice ..thanking ..
This applies to the Audi TT thanks
Do you have a video on the module recoding element?
I tried to scan my neighbors 2003 Beetle, same issue. It worked 3 days ago so I'm not sure what's going on.
great video
nice video but where do we get the wiring diagram and specified values like resistance?
the vw jedi..... good work. wonder who the thumbs down was
Great question. I wonder that all the time lol
Well done, ty
great tips
your voltmeter like scanner danner's one hhhh
where do you got the abs wiring diagram ?
From where can i get that wiring diagram?
Wonder what goes bad inside the module ? Don't look inside during working hours. Thanks for sharing and easy to follow along.
stupid low-quality solder joints no doubt.
tom can I make a suggestion. I also live with these current flow diagrams being an audi tech. I find when printing the current flow off set the printer to "landscape" layout and it prints of in a better format 'uses more of the paper on the diagram rather than the wording which is much easier to see and also staple them together like a book. cheers for listening. I'm a big fan of Paul D and also started following yourself. cheers
Thanks Stephen. I appreciate the tip
It would have good to see the can signal with the module plugged in
Great video.. Wondering if u can test from abs fuse ?
I have all voltage and groud but i dont have the orange cable populated
Good info as always thanks for sharing really enjoy ur video specially the one with no comm one question where did you connect to check the the terminating resistance . cheeeeeers
From the same place that you plug the scanner, you'll need the diagram, and disconnect the battery to check the continuity me
where can i find that packet
Hello sir nice info ...y question is what if we get 120 ohms
also tom can you tell me where you got the print out of the checks that you had regarding the ABS module? was it from ELSA ?
It was from Elsa
What would it mean if there is no resistance on the orange wires? Would this explain an internal module memory error?
It would mean there’s an open some where. Either in wiring or in the module with the resistors. How are you checking the circuit?
Does the CAN BUS always have the Terminating 120 ohm resistors regardless makes, models ?
Yep.
and don't forget it will be terminated with 120 ohm at two locations, so you should see around 60 ohms total if everything is plugged in and good.
For high speed CAN, yes. It is part of the network standard for high speed CAN and is driven by the intrinsic impedance of the CAN wiring.
There is an older low speed CAN that was used in some cars for a while that did have a different terminating resistor, but those, if I remember right were built into the modules on that system.
two locations.. one in the ecm one in the abs? when he unplugged the abs connector and got 60ohms that pretty much says no resistor in the abs, correct?
There is a 120 ohm resistor at each end of the CAN lines. They may or may not be located at the same place a CAN transmitter connects, but in high speed CAN are not suppose to be in the module. I've seen them incorporated in connectors just past where the module electrically ties in. The two 120 ohm resistors are in parallel when you measure between CAN Hi and CAN Lo, so the resistance reading is ~60 ohms.
There is nothing wrong with the CAN twisted pair. There is some ringing on the line, but it is on both CAN Hi and CAN Lo so cancel out when you subtract CAN Lo from CAN Hi. The modules actually read the difference between CAN Hi and CAN Lo. If the oscilloscope can do math functions, subtracting (CAN Hi - CAN Lo) would show a clean 0 to 2 volt signal. Similar if you probed between CAN Hi and CAN Lo instead of referencing to ground.
I had the same problem with my 2000 Passat. Sent ABS model for repair, less than $100. Only needed to send electronic side of module.
Nice. I wish I knew how to fix them
I can't get to clear my abs break modules
What about the other side of connector that is in contact with the module pins??
A pin contact issue is possible but these modules are pretty common. A better test would be checking the network resistance from the pin side if you have the right terminals to fit in the connector.
Oh my favorite money maker for the past 12 years
Well that and missing fuses of course 😉
Keith, can a shorted brake booster vacuum sensor (like on ford fusion for ex) make abs module a no comm?
MrBorntoroll if its pulling down the reference voltage circuit possibly
New Level Auto what bad modules?
90%- bad ABS module. Don't waste time by diagn. Extremly hard to repair module inside. [tiny wires-less like hair in silicone. ] My sellf spoiled 2 modules trying fix[4-5 hrs.] Buy rebuild module . Watch letter behind p.# !!! and org. code !!!
great video can you please tell me where you got the data on the resistance etc as i have the same wiring diagrams but cant seem to find the data many thanks
If you look in diagnostic procedures for the no comm fault. It should give specs in terminating resistance
many thanks
Where would a guy find the same information for a 2006 Audi A4. I'd like to test the wiring before just assuming its the Modul. PS. Great Video, buying a test light!
pop off abs module cover and check ground pin with ground on scheme, its common thing, just solder ground two wires to cooling rad and done.
I’d like to try and start doing module repair. Maybe someday
what happened to the verus Tom? you've not been using it for a few videos now
Il get back to it. Just felt like using the factory tool for a change
Im having this issue with my Touareg going to test the resistance if that’s good I guess the modules gotta go
You have to check powers and grounds too
Can u help me out have all good power and grounds.but my oms are 160
On the orange
There are 2, 120ohm resistors In parallel. When they are connected In Parallel you should read 60ohms on a good circuit. It sounds like you have open circuit. Where are you doing your resistance measurement? And are all the modules plugged in when your doing it? You might be unplugging a module that has one of the resistors in it and that would change your ohm reading.
in mercedes truck i check pin out of can bus and they lead me to transistors inside ABS then i change them 80% works fine 😂
Hi
What if the resistance is not within the specs???
What was your measurement? Could be wiring or could be a faulty terminating resistor.
@@PositiveLeadDiagnostics
17-18 ohms
Hello
I was able to solve this problem
I have the same problem on my vw passat of the year 2000
What was the solution?
Replacing the abs module
ok, thank you
That lamp sucks more electricity than that ABS pump 😛
That's not a 2001
ref
omg that’s just to much not the video the module shit i just want the lights to go off lol