1994 Audi Coupe 2.0e ABS issues

[m50yre]

Hi guys.
Wonder if you can help.
I have been fixing up an 80 Coupe for the past couple of years. Its now ready for MOT but i cannot get the ABS light out. Now all brakes have been removed, renewed, subframe off etc so everything is new. I cannot remember if the light was on when i got it, as it didnt run.

Ive had it on VCDS and the ABS controller cannot be communicated with.

Ive checked the ABS ECU and and got a spare to try that but makes no difference.

Only thing i can find is that the ABS ECU only gets a 6v feed - without a diagram im not sure if thats enough or if the only feed required?

Any thoughts?

[Ben]

Have you checked the fuse on the ABS relay? it's located under the dash behind the ign switch:



I've had a relay die, which is why I have a photo of one

[m50yre]

Hi, i saw this on another forum so went looking for that relay, but cannot find it, do all Coupes have them? Cheers

[m50yre]

IMG_0269.jpg

IMG_0270.jpg

[Mellis46]

If its not where Ben said that ABS relay also can sometimes live under the back seat...

[Ben]

Looking through some Audi B4 pdf's, it states (for LHD):

Removing and installing combi relay
Location:
Front left, beneath instrument panel in auxiliary relay plate
=> Current Flow Diagrams, Electrical Fault Finding; Fitting Locations
Note:
Switch off ignition for removal and installation. Not applicable as of model year 1993.

So you don't have one to check. It also says about the ABS ECU:

Prior to removal on vehicles as of model year 1993 interrogate fault memory with fault reader -V.A.G 1551-.

I put the pdf here if you want to have a read up: http://www.brita.plus.com/80q/FWD_Running_gear.pdf right click the link to download

[mikes2]

For a 94 car, there is no relay. It's all contained in the ecu under the rear seat.

If you start the car up, the ABS light should go off within 5 seconds. If it doesn't it's likely a pump / modulator fault since you've already swapped the ecu.

There are 2 relays in the modulator which can be swapped out

[m50yre]

Thanks guys. Nah light stays on. It’s not turned a wheel for over ten years so I do wonder if once it’s had a drive it’ll sort itself out. I’ll keep you posted.
Cheers

[Mellis46]

Good luck

[m50yre]

Originally Posted by Ben

Looking through some Audi B4 pdf's, it states (for LHD):

So you don't have one to check. It also says about the ABS ECU:

I put the pdf here if you want to have a read up: http://www.brita.plus.com/80q/FWD_Running_gear.pdf right click the link to download

Thanks for the pdf. VCDS cannot read my ABS, is that normal? I had a 95 one years ago and I’m positive Vagcom could read abs on it?