Diagnostic Aids

Ensure fuel pressure is within specifications. Check MAP sensor for correct values. A MAP senor that reads high vacuum will cause a lean condition. Check for fuel contamination. Small amounts of water in fuel tank can cause DTC P0171 to set. An intermittent malfunction may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, or poor terminal-to-wire connections before component replacement.