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) or the powertrain control module (PCM) 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 P1189 will set.

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.
- 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
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 and IPC replacement, setup, and programming.