Good news for what appeared to be serious problem. I would urge anyoen that has a dash light indidcating low oil pressure or check engine light to check all related harness and connections for corrosion or weak connections.My 2002 Audi S4 had a DTC showing torque converter problem,the tranny wasnt shifting properly.I bought a good used tranny and installed it,tranny did the same thing shifted bad,checked the code and it was the same torque converter code.Different mechanic checked the harness to the trans and found corrosion,cleaned the connections and wha la, no codes tranny works great!(Guess I bought a tranny just for fun). My 2002 A6 3.0 runs great oil pressure light would come on after it warmed up.New pressure switch,new synthetic oit,dropped pan check scrreen and pickup,still did same thing. Audi said I need new oil pump,I sinsisted on oil pressure check did and found my pump was well in specs.
After two days of trying to find wiring schematics found all the grounds for the engine,#10 on top the ngine looked ok,but had corrosion underneath,cleaned the grounds,no light and runs great.Lesson is always check harness and contacts for corrosion on VW,s and Audis.May not always work but it sure is a nice feeling when it does