Hi,

1) YOu have to readout and clean the error memory of the airbag ECU, but not at the readout port in front of the passanger seat, but directly at the ECU (I always forget where it is, but Audi knows).

2) The sensor for the oil pressure could be broken which controls the warning light - shorten it (or disconnect it, don't know if it's an opener or a closer) and you'll find out.

3) I'm pretty sure that your Alternator's wiring (Spulen!) (don't know the expression and am in a hurry) could be broken, had the same on mine. Let it check. Other possible thing: When you changed the battery, you forgot to tighten the screws at the connectors, so they are loose. Had that also, check it.

Many regards (am in a hurry, sorry)

Bastian

Das Buch zum Audi V8