Dirty maf sensor ($8 fix) If there’s a vacuum leak, the sensor’s doing its job by telling the ecm “i see excess oxygen.” when the sensor is the problem To fix the p0171 code, you need to check and repair vacuum leaks, repair low fuel pressure, or replace any faulty sensor that can cause a lean.
Code P0171 - System Too Lean: Symptoms, causes, common problems, diagnostic
P0171 or p0174 readings indicate too lean of a system in one of your cylinder banks
Learn common causes and solutions to these trouble codes.
A p0171 indicates a lean condition on bank 1, while a p0174 indicates a lean condition on bank 2 Most of the time, these codes are caused by. If the p0171 is combined with the p0174 code, it's very likely that the problem is caused by an intake leak If there are no intake leaks, the next step is to replace.
