The engine oil pressure (EOP) sensor changes resistance based on engine oil pressure. The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuit of the EOP sensor. When the engine oil pressure is high, the sensor resistance is high and the ECM/PCM senses a high signal voltage. When the engine oil pressure is low, the sensor resistance is low and the ECM/PCM senses a low signal voltage. The ECM/PCM sends the engine oil pressure information to the instrument panel cluster (IPC) via the class 2 serial data circuit.

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Instrument Cluster Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, perform the engine oil gage sweep test with the scan tool. Verify that the engine oil pressure gage sweeps from its low to high position.

⇒	If the engine oil pressure gage does not sweep, replace the IPC.

2. Engine running, observe the scan tool Engine Oil Pressure Sensor parameter. The reading should be between 0.5-4.5 volts.
3. Verify the engine oil pressure, refer to:

•	Oil Pressure Diagnosis and Testing for the 6.6L engine

•	Oil Pressure Diagnosis and Testing for the 8.1L engine.

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

⇒	If greater than the specified range, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM/PCM.

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

⇒	If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the ECM/PCM.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM/PCM.

4. Install a 3-amp fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Engine Oil Pressure Sensor parameter is less than 0.4 volt.

⇒	If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM/PCM.

5. Install a 3-amp fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 3. Verify the scan tool Engine Oil Pressure Sensor parameter is greater than 4.6 volts.

⇒	If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM/PCM.

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

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.