Circuit/System Testing

With the ignition ON, install a scan tool and observe the Engine Oil Pressure Switch parameter in the ECM Engine Data list.

• If the Engine Oil Pressure Switch parameter displays OK, replace the IPC.
• If the Engine Oil Pressure Switch displays Low, disconnect the engine oil pressure switch, start the engine, and observe the Engine Oil Pressure Switch parameter.
• If the Engine Oil Pressure Switch displays OK, check for poor connection at the harness connector of the EOP switch.
• If the harness connector is normal, replace the EOP switch.
• If the Engine Oil Pressure Switch displays Low, check the signal circuit of the EOP switch for a short to ground.
• If the signal circuit tests normal, check for a poor connection at the harness connector of the ECM.
• If the harness connector is normal, replace the ECM.