2004 Audi A4 B6 1.8T P0171 Code: Turbo Spooling Issues and Symptoms
Hi, I own a 2004 Audi A4 B6 1.8T and am currently experiencing a P0171 diagnostic code. The issue manifests when the turbo starts to spool but then abruptly stops, resulting in a significant loss of power. When the headlights are on, the engine runs unevenly for about 4 miles before returning to normal operation with proper turbo spooling. This behavior recurs after approximately 5 to 6 consecutive start-ups. I'm trying to identify if there's a specific component responsible for this behavior. Any insights or suggestions would be greatly appreciated. Regards, Russ.
I don't work with Audi vehicles, but I can share some information about P0171: https://www.obd-codes.com/p0171. It's important to note that this code does not necessarily indicate a failed part — it may point to an issue in the air-fuel mixture or sensor readings. Have you checked for additional diagnostic codes? If so, what kind of scanner or OBD2 reader are you using?