Circuit DescriptionThe engine oil pressure switch is used by the ECM to monitor the lubricating oil pressure. The oil pressure switch is normally closed when the engine is not operating and open when the engine is operating and oil pressure is present.
Component LocationThe location of the oil pressure switch varies by engine model.
Conditions for Running the DiagnosticsThis diagnostic runs when the keyswitch is turned ON and before engine speed is detected.
The diagnostic only runs once per trip.
Conditions for Setting the Fault CodesThe ECM detects that the engine oil pressure switch is indicating that oil pressure is present (switch is open) at initial key ON for two consecutive key cycles, when the ECM expected to see no oil pressure (switch closed) at key ON.
Action Taken When the Fault Code is ActiveThe ECM illuminates the amber CHECK ENGINE lamp and/or malfunction indicator lamp (MIL) immediately when the diagnostic runs and failsA default value for the engine oil pressure reading is used.Conditions for Clearing the Fault CodeTo validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop-and-go city driving and steady state highway driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.To validate the repair using a Chassis Dynamometer, utilize a routine that incorporates acceleration and motoring events, steady state highway operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.The fault code status displayed by INSITE? electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The ECM will turn off the amber CHECK ENGINE lamp after the diagnostic runs and passes.For On-Board Diagnostic (OBD) engines, the ECM will turn off the MIL after three consecutive trips where the diagnostic runs and passes.The Reset All Faults command in INSITE? electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.
Shop TalkPossible causes of this fault code include:
Damaged engine oil pressure switchOpen circuit in the engine oil pressure switch SIGNAL wireDamaged ECMShort circuit in the engine oil pressure switch signal wire to a voltage source.
Possible Cause:1) Engine Oil pressure switch failure2) Engine Harness3) ECM failure