2002 Audi A4 B6 1.8t No Response from OBD2

[RC490]

My 2002 Audi A4 B6 1.8T does not respond to any obd2 scanner and I have no clue what it could be. Their is a stage 2 ecu in it and the airbag light flashes but I had no problems with it until now. The car runs and drives perfectly fine, I started with the broken radio and fixed it, nothing happened. Then I pulled the abs harness nothing happened. Now I’m just lost.

[A4-Mike]

I have the same car same problem the only ones that read it are OBDELEVEN or Rosstech

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[RC490]

I can’t even get my car inspected because of this problem and I can’t try another ecu because of the immobilizer unless i get it tuned. Maybe something tripped in the ecu code. I just need ideas, anything would help. Thank you

[A4-Mike]

I bought the OBDeleven and haven't had a problem with it reading and adjusting settings in my ecu.

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[RC490]

I can try the rosstech scanner from one of my friends but the inspection part is where I’m stucK because the scanners they use doesn’t pick up anything.

[A4-Mike]

I can try the rosstech scanner from one of my friends but the inspection part is where I’m stucK because the scanners they use doesn’t pick up anything.

Oh Wow sounds like they need new scanners, I'm Australian and the state I LI e in you just get a Roadworthy Certificate when you buy the car and that's it no yearly inspections.
I really do feel sorry for all the bullshit you guys have to go through just to have a car on the road were as I can modd the shit out of it and not have any hassle.

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[ReinS]

You should use VAG compatible scanner to read abs, airbag etc. modules. Rosstech of course is the best. Basic obd2 scanner can only read your engine module. With no connection seems that there's no response from K-line. It's located on pin 7 (green/red wire) in DLC. At first i would check fuses 12 and 31 in fuse panel. Those two give power to DLC. From fuse 12 to pin 16(DLC) and from fuse 31 to pin1(DLC). If there's no feed, you can't get connection.

[Gin+]

[RC490]

I appreciate all this info, if you guys have any other ideas let me know. I’m gonna try all this tomorrow. I’ll keep you updated

[RC490]

Tested the k line off the radio and that’s fine. Change the MAF sensor, even tho that has nothing to do with it I’ll just add it in. I ripped out the ac and compressor along with the whole harness. Still getting no response.

[Furly]

find someone local with rosstech cable and see if it can do a scan and read. if it does...find another inspection shop. if it cant read your ecu make sure nothing shorted and fried it. i had my maf wiring melt and the wires touched and shorted my ECU. had to buy a replacement ecu and have the immobilizer defeated. it could be the shops scanner. most smog shops use shitty cheap obd2 scanners and they dont take care of them at all.

[asg1290]

Check your fuses. I had a bad fuse cause this for me.

[ReinS]

Tested the k line off the radio and that’s fine. Change the MAF sensor, even tho that has nothing to do with it I’ll just add it in. I ripped out the ac and compressor along with the whole harness. Still getting no response.

How you tested K-line? You can rip whole car apart thinking "maybe this" with zero effect. B6 is smart enough to tell you what is wrong with her. You only have to ask correctly. Like Google. If you can't get any connection or response from any module with Rosstech, then at first i would check if pin 16 on DLC get +12v as shown on Gin+ posted picture.

[EuroxS4]

Do you have a aftermarket radio installed??I've seen aftermarket radio do weird things in these cars.Other than that all you need is power and ground at obdII connector and Kline.as long as you have all those your good.

Or install a ecu that has its immobilizer defeated or clone the existing immobilizer.Also what kind of tune do you have??Some tuners disable reading of ecu over OBD but this is usually not a problem when checking faults.

[RC490]

Currently I’m checking the ccm under the driver side seat, I’m at the what if game. I do have a reflet tuning stage 2 tune but didn’t have problems at all with a cheap code reader until recently. I have the stock radio in and I just recently fixed it with no luck afterwards. It’s just what if’s. About to kick the car to the curb.

[EuroxS4]

Well I will say this if a cheap obd scanner can talk to it you shouldnt have a problem.Maybe the issue is with their hardware??There is a fuse for the OBDII connector on the side of the dash.Check make sure its not blown.

[RC490]

The obd gets power but no response

[RC490]

It was the ccm

[Larhal]

Hi RC490,

Did you replace the CCM with the same part number or did you upgrade it to a newer part number?

Larhal

[RC490]

I used one from a 2003 A4 and everything works like it’s supposed to and the OBD2 port gives me codes now. It was the last thing I check due to the extent to get to the box.

[Larhal]

Thanks for the information. DO your key remotes still work?