Engine Oil Pressure Indicator Always On

Engine Oil Pressure Indicator Always On

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

Circuit Description

The engine oil pressure (EOP) sensor changes resistance based on engine oil pressure. The engine control module (ECM) monitors the signal circuit of the EOP sensor. When the oil pressure is high, the sensor resistance is high, and the ECM senses a high signal voltage. When the oil pressure is low, the sensor resistance is low, and the ECM senses a low signal voltage. The ECM sends the engine oil pressure information to the instrument panel cluster (IPC) via the serial data circuit.

Reference Information
Schematic Reference

Instrument Cluster Schematics (Instrument Cluster Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

* Indicator/Warning Message Description and Operation (Indicator/Warning Message Description and Operation)
* Instrument Cluster Description and Operation (Description and Operation)

Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EOP sensor.
2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal A and ground.

• If greater than 1 ohm, test the circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal B and ground.

• If less than 4.8 volts, test the circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the ECM.

• If greater than 5.2 volts, test the circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Install a 3-amp fused jumper wire between the signal circuit terminal C and the low reference circuit terminal A. Verify the scan tool Engine Oil Pressure Sensor parameter is less than 10 kPa (1.5 psi).

• If greater than 10 kPa (1.5 psi), test the circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. Install a 3-amp fused jumper wire between the signal circuit terminal C and the 5-volt reference circuit terminal B. Verify the scan tool Engine Oil Pressure Sensor parameter is greater than 550 kPa (80 psi).

• If less than 550 kPa (80 psi), test the circuit for a short to ground. If the circuit tests normal, replace the ECM.

6. Ignition ON, perform the lamp test with the scan tool.

• If the engine oil pressure indicator does not turn off when commanded, replace the IPC.

7. If all circuits test normal, test or replace the EOP sensor.

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 (Programming and Relearning) for the ECM and IPC replacement, setup, and programming.