ABS wiring Loom diagram

[ed a6 1.8T]

Anyone got a wiring diagram for a A6 1.8 T 1999? Got a intermitant connection to the ABS ECU but there is no fault on the ECU or on the dash. (Sent both off to be tested) Have had a look at the loom, cant see anything untoward. Would like to buzz out the loom etc.

Cheers

Ed

[Sparky Charlie]

I'm a bit confussed. You say you have an intermittant problem with the abs but not faults on dash or ABS unit.

Do you not have the ABS light come on (after it's lamp check at start up) ?

If you do a fault has been logged.

If you don't, how do you know you have a fault?

I'm sorry I don't have a ABS harness diagram.

Charlie

[ed a6 1.8T]

the fault code was intermitant connection (Cant remember code exactly, will reconnect to see what it was). on the whole the ABs warning lamp and display and buzzer comes on when I start the car. It will sometimes not come on for about 10 miles but will come on with out fail after this time. It will go off after a while but usualy stays on. No ABS when warning on up on dash. was a lot less intermitant but its at the stage as described above now.

[Peter D]

Yes I do. Do you have EDL and ARS. I need your email address, put a couple of spaces in it to avoid phishing. Regards peter

[ed a6 1.8T]

I dont have EDL, not sure on ASR, probably not as I dont have traction control. its a front wheel drive car, may be you get these on quattro systems only? email is edward_staveley @ hotmail . com. thanks in advance!

[ed a6 1.8T]

OK so plugged car in this morning and was able to connect to the ABS got the following code

01203 - Electrical Connection between ABS and Instrument Cluster
03-10 - No Signal - Intermittent

Looked at connections I could see with nothing obvious. tried to invoke a signal loss by moving wiring that I could reach which is behind instrument cluster and from ABS ECU to bulkhead. It disapears through the bulkhead at this point.

I have looked at the diagrams that Peter kindly sent but they dont mean an auful lot to me! I am used to much more basic diagrams from cars long dead. Not sure what part of diagram is for my cvar as its only got ABS and no other features like ASR etc.

Does anyone know what wire goes to which connection on the loom?

Any thoughts most welcome

[Peter D]

The only signal I can see goint to the Dash is the ABS warning light from pin 32 of the ABS control unit to pin T32/19 of the dash insert and the diagnostic comms connection from pin 46 of the ABS unit to T32/25 of the insert. Look at 0008 page 7. Regards Peter

[ed a6 1.8T]

yep , that makes sense now I have a starting point. My viewer has made the diagram a little fuzzy, but now I know what I am looking at.
Unfortunately, it has not enabled me to find a problem! All wiring buzzes out and the junction in the front passenger well looks OK. I have even disconnected the wheel sensors at the connectors in the passenger footwell and had that reported on the dash as well as ABS failure! This would mean that the ABS ECU is functioning to a degree I think as the signal from the sensors goes straight into the ABS ECU.
AAAAAAAARRRRRRRRRRRRRRRRRRRRRRRRRRRR!

[Sparky Charlie]

Your code says to me that the dash is not always recieving data from the ABS unit. This could mean that there is a break in that wire, or it could be that there is no expected data coming from the ABS unit, say from the ABS unit loosing it's supply or it's ignition feed that might switch it on. Check you have a good earth (brown wire) to the ABS and there is no difference in the earth to the dash.

Charlie