Engine Oil Pressure Indicator Malfunction

Engine Oil Pressure Indicator Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






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. When the oil pressure is low, the ECM sends a serial data message to the body control module (BCM) requesting the EOP indicator turned ON. The instrument panel cluster (IPC) illuminates the EOP indicator when the IPC receives a serial data message from the BCM requesting the EOP indicator turned ON.

Reference Information

Schematic Reference

* Instrument Cluster Schematics Instrument Cluster Schematics

* Engine Controls Schematics

Connector End View Reference

Component Connector End Views A/C Compressor Clutch

Description and Operation

Instrument Cluster Description and Operation Instrument Cluster

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

Engine running, verify the scan tool Engine Oil Pressure Switch parameter is OK.

If not the specified value, refer to Oil Pressure Diagnosis and Testing Oil Pressure Diagnosis and Testing.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EOP switch.

2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal B and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.

• If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

4. Ignition ON, install a 3 A fused jumper wire between the signal circuit terminal A and the ground circuit terminal B. Verify the scan tool Engine Oil Pressure Switch parameter is Low.

• If not the specified value, test the signal circuit for an open/high resistance. If circuit test normal, replace the ECM.

5. Ignition ON, command the IPC indicators OFF with the scan tool.

• If the EOP indicator does not turn OFF, replace the IPC.

6. If all circuits test normal, test or replace the engine oil pressure switch.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Engine Oil Pressure Sensor and/or Switch Replacement Service and Repair

* Control Module References Control Module References for ECM or IPC replacement, setup, and programming