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)/powertrain control module should detect a low signal voltage input. With the engine running, the pressure switch opens, and the ECM/PCM should detect a high signal voltage input. The ECM/PCM tests the state of the EOP circuit with the ignition switch turned ON, and the engine turned OFF. If the ECM/PCM detects a high voltage input on the EOP signal circuit, DTC P0520 sets. When the oil pressure is low, the ECM/PCM sends a GMLAN serial data message to the body control module (BCM) requesting the EOP indicator turned ON. The IPC illuminates the EOP indicator when the instrument panel cluster (IPC) receives a serial data message from the BCM requesting the EOP indicator turned ON.

REFERENCE INFORMATION

Schematic Reference
- Instrument Cluster Schematics
- Computers and Control Systems Schematics for the 2.0L engine
- Computers and Control Systems Schematics for the 2.2L engine
- Computers and Control Systems Schematics for the 2.4L engine

Connector End View Reference
- Instrument Panel, Gages, and Console Connector End Views
- Powertrain Control Module (PCM) Connector End Views for the 2.0L engine
- Engine Control Module (ECM) Connector End Views for the 2.2L engine
- Engine Control Module (ECM) Connector End Views for the 2.4L engine

Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs

Scan Tool Reference
Scan Tool Data List

CIRCUIT/SYSTEM TESTING
With the ignition ON, install a scan tool, and observe the Engine Oil Pressure Switch parameter in the ECM/PCM Engine Data list.
- If the Engine Oil Pressure Switch displays Ok, replace the instrument panel cluster (IPC).
- If the Engine Oil Pressure Switch displays Low, then 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 engine oil pressure switch.
- If the harness connector is normal, replace the engine oil pressure 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 for a poor connection at the harness connector of the ECM/PCM.
- If the harness connector is normal, replace the ECM/PCM.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. Engine Oil Pressure Sensor and/or Switch Replacement for the 2.0L engine.
2. Engine Oil Pressure Sensor and/or Switch Replacement for the 2.2L engine.
3. Engine Oil Pressure Sensor and/or Switch Replacement for the 2.4L engine.
4. Control Module References for the ECM/PCM replacement, setup, and programming