replaced mass air flow sensor and fuel pump on 02 camry but p0171 code comes back

Question

02 camry with long term fuel trim out of value. p0171 keeps coming back after replacing parts. values for air fuel sensor seem okay. what to do about code coming back.

Answer 1

Hi there,

I would disconnect the battery over night to try and reset the long term fuel trims. They can cause the code even when the issue is resolved. Other causes for the lean code can be a bad O2 sensor or intake manifold leak. You can also have a timing issue that is leaving a valve open ever so slightly, this will cause a lean mix. Check for a plugged or partially blocked converter.