DTC P0172: 1/1 Fuel System Rich: Description

System is monitored with engine running in closed loop mode, ambient temperature more than 20°F (-7°C) and altitude less than 8000 feet. DTC will set when PCM determines 1/1 fuel system has been too rich for 2 trips. Freeze frame will be stored and MIL will illuminate. Possible causes are: restricted fuel supply line, fuel pump inlet strainer plugged, defective fuel pump module, defective 1/1 HO2S, faulty EVAP system operation, 1/1 HO2S signal circuit open or shorted to voltage, Throttle Position (TP) sensor voltage more than .92 volt with throttle closed, defective TP sensor, defective Manifold Absolute Pressure (MAP) sensor, defective Engine Coolant Temperature (ECT) sensor, engine mechanical problem, defective fuel filter/pressure regulator, or defective PCM.