ABS & Airbag MIL [Archive] - Audi Forums

: ABS & Airbag MIL

11-19-2011, 10:27 PM
My sweetheart's 99 A4 1.8T has these lights on all the time. Neither controller will scan. Intrestingly, the engine ECU will only communicate with the scan tool when the ABS controller is unplugged. The transmission controller only scans in Expert Mode. I checked all positive inputs to the ABS unit - good. I checked continuity between ABS and DLC - good. The schematic of the bus shows multiple controllers are tied together that connect to pin #7 on the DLC...Where are they all tied together? Is there something that knocks out the bus? Is there a common problem? Sure would appreciate any tips. Thanks.