DTC P0172:00: Notes

DTC P0172:00	Fuel trim system too rich
DETECTION CONDITION	The PCM monitors short term fuel trim (SHRTFT) and long term fuel trim (LONGFT) values when closed loop fuel control. If the LONGFT and the sum total of these fuel trims exceed preprogrammed criteria, the PCM determines that the fuel system is too rich. Diagnostic support note This is a continuous monitor (fuel system). The MIL illuminates if PCM detects the above malfunctioning condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM. PENDING CODE is available if PCM detects the above malfunction conditions during first drive cycle. FREEZE FRAME DATA (Mode 2)/Snapshot data is available. The DTC is stored in the PCM memory.
POSSIBLE CAUSE	Misfire Erratic signal to PCM APP sensor signal malfunction ECT sensor signal malfunction MAF sensor signal malfunction TP sensor signal malfunction VSS signal malfunction A/F sensor heater malfunction A/F sensor malfunction A/F sensor loose Exhaust system leakage A/F sensor deterioration MAF sensor malfunction Improper operation of ignition system Fuel supply system malfunction or improper fuel line pressure Pressure regulator malfunction Fuel pump malfunction Fuel leakage on fuel line from fuel distributor and fuel pump Fuel filter clogged or restricted Fuel return hose clogged Improper connection of purge control system Improper operation of EGR valve system Improper operation of variable tumble solenoid valve Improper operation of variable valve timing control system Improper operation of fuel injector Improper operation of PCV valve PCM malfunction