Volvo V70 OBD2 Code P0171: Fuel Trim Bank 1 - Diagnosis and Next Steps
The oxygen sensor in bank 1 has already been replaced, but the check engine light remains on with OBD2 code P0171 (Fuel Trim Bank 1). Despite this repair, the issue persists. What should be the next diagnostic step to resolve this problem?
Replacing the oxygen sensor was likely unnecessary. Make sure you installed an authentic Volvo part rather than a generic or aftermarket sensor. Regarding code P0171: are there any other related diagnostic codes? Check for vacuum leaks and perform a fuel pressure test using an accurate fuel pressure gauge to identify potential issues in the fuel system.