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Engine Oil Pressure Indicator Always On



ENGINE OIL PRESSURE INDICATOR ALWAYS ON




DIAGNOSTIC FAULT INFORMATION

IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

CIRCUIT/SYSTEM DESCRIPTION
The engine oil pressure (EOP) switch is a normally closed switch that opens with the proper oil pressure. With the ignition switch turned ON and the engine not running, the engine control module (ECM) should detect a low signal voltage input. With the engine running, the pressure switch opens, and the ECM should detect a high signal voltage input. The ECM tests the state of the EOP signal circuit with the ignition switch turned ON, and the engine turned OFF. If the ECM detects a high voltage input on the EOP signal circuit, DTC P0520 sets. The instrument panel cluster (IPC) illuminates the EOP indicator when the IPC receives a serial data message from the ECM requesting the EOP indicator turned ON.

CIRCUIT/SYSTEM TESTING
1. 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 displays OK, replace the IPC.

2. Disconnect the EOP switch, start the engine, and observe the Engine Oil Pressure Switch parameter in the scan tool.
- If the Engine Oil Pressure Switch displays OK, check for poor connection at the harness connector of the EOP switch.

3. If the harness connector is normal, replace the EOP switch.
- If the Engine Oil Pressure Switch displays Low, check the signal circuit of the engine oil pressure switch for a short to ground.
- If the signal circuit tests normal, check the ground circuit of the EOP switch for an open.
- If the ground circuit tests normal, replace the ECM/powertrain control module (PCM).

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Engine Oil Pressure Sensor and/or Switch Replacement
- Control Module References for the ECM replacement, setup, and programming
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