How Do I Fix the P0171 Code? You can resolve the Bank 1 system running too lean error using a few approaches. Depending on the issue’s cause, you may be able to turn the check engine light off by completing one or more of these repairs: Change out the fuel pump and fuel filter....
LTFT values that go as high as 20 or higher will usually set a P0171 or P0174 lean code and turn on the Check Engine light.High positive LTFT fuel trim numbers due to a lean A/F mixture may be the result of dirty fuel injectors, a dirty mass airflow sensor, vacuum leaks at the...
LTFT values that get up around 20 to 25 percent will usually set a P0171 or P0174 lean code. LTFT values that drop down to negative 20 to 25 will usually set a P0172 or P0175 rich code. This scantool is displaying a STFT value of 25 percent. Normally that would indicate a proble...
be stored. In other cases, an immobilizer code might be stored. In general, anti-theft or immobilizer codes must be resolved before proceeding with a cranking, no-start diagnosis. FUEL PRESSURE ISSUES If scan tool data indicates a fuel pump duty cycle value, you might nd yourself dealing wit...