VW Touareg ABS fault

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United Vehicles

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Hi, We are after some help with an ABS fault on a 2003 VW Touareg. The chassis number of the vehicle is WVGZZZ7LZ4D020262. There is no communication with the ABS ecu. We have established that there is no live feed to the ABS ecu on terminal 4. With some help from autodata (we are a paying subscriber of this and haynes pro, neither have the complete diagram online) we have established that this live comes from fuse 38 of the interior fuse box. There is no live at this point nor the adjacent fuses. The live origniates from the terminal 15 relay under the NSF seat. This relay has lives present but the earth to pull the relay coil windings in is not present. Could anyone please help with what provides the earth for this relay, where its located and what pin number this earth wire goes to?
Many thanks in advance
Simon
 
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Uwe

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Since this question doesn't involved VCDS in any way, moving to General VW/Audi Repair.

-Uwe-
 
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dieseldub

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Hi, We are after some help with an ABS fault on a 2003 VW Touareg. The chassis number of the vehicle is WVGZZZ7LZ4D020262. There is no communication with the ABS ecu. We have established that there is no live feed to the ABS ecu on terminal 4. With some help from autodata (we are a paying subscriber of this and haynes pro, neither have the complete diagram online) we have established that this live comes from fuse 38 of the interior fuse box. There is no live at this point nor the adjacent fuses. The live origniates from the terminal 15 relay under the NSF seat. This relay has lives present but the earth to pull the relay coil windings in is not present. Could anyone please help with what provides the earth for this relay, where its located and what pin number this earth wire goes to?
Many thanks in advance
Simon
Pop up the seat as if you're changing the battery (or at least poking at the term 15 relay under there, which you will be doing anyway). Pull the carpet up.

Unwrap the wiring harness from the plastic router under the seat to at least mid way up where the harness goes under the "dead pedal".

The J518 Access/start module provides the ground to energize the relay. It should be a brown/red wire. For whatever reason, this wire has a splice in the area I just told you to unwrap and inspect.

The wires are sort of welded together, but their only protection from moisture is some flimsy tape. Since it's a VW, it will leak water at some point and make it to this area under the carpet, which will eventually corrode the various spliced wires in this region of the harness.

Find that brown/red wire splice, unwrap the tape and you may very well find a lot of corrosion and a wire that broke because of it. Can also check for ground on the side of the wire heading upwards and behind the dash, switch the key on and see if you're getting ground from that half of the splice to verify there isn't some other issue further back.

Re-splice the wire, check and see if you're now getting ground at the 85 terminal (pin 4 on the socket I think) of the relay. See what you get.
 
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United Vehicles

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Well that information was far more accurate than I was ever expecting. Thank you very much for that. The information was spot on. I was hoping that someone could tell me the terminal number on the J518 module that the relay brown/red wire went to but the information went one step further. The fault was exactly as posted
 
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