Engine Oil Pressure Gauge Inaccurate or Inoperative
Engine Oil Pressure Gauge Inaccurate or Inoperative
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) sensor changes voltage based on the engine oil pressure. The EOP sensor is a 3-wire sensor comprising of the signal circuit, the low reference circuit and the 5 V reference circuit. The engine control module (ECM) supplies 5 V to the EOP sensor via the 5 V reference circuit and provides ground via the EOP low reference circuit. The ECM monitors the signal circuit of the EOP sensor to determine the engine oil pressure sensor voltage is within the normal operating range of approximately 1-4 V. When the engine oil pressure is high, the EOP sensor voltage is high and the ECM senses a high signal voltage. When the engine oil pressure is low, the EOP sensor voltage is low and the ECM senses a low signal voltage. The ECM sends the EOP 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)
* 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 (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Engine running, observe the scan tool Engine Oil Pressure Sensor parameter. The reading should be between 0.2-4.8 V.
2. Ignition ON, with a scan tool perform the IPC Gauges sweep test.
• If the engine oil pressure gauge does not sweep from its low to high position, replace the IPC.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the engine oil pressure (EOP) sensor.
2. Ignition OFF, test for less than 1.0 ohm between the low reference circuit terminal listed below and ground:
* Terminal C, 3.6L engine
* Terminal 1, 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L engines
• If greater than the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal listed below and ground:
* Terminal B, 3.6L engine
* Terminal 2, 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L engines
• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Verify the scan tool Engine Oil Pressure Sensor parameter is less than 0.2 V.
• If greater than the specified range, test the signal circuit terminal listed below for a short to voltage. If the circuit tests normal, replace the ECM.
* Terminal 3, 3.6L engine
* Terminal A, 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L engines
5. Install a 3 A fused jumper wire between the signal circuit terminal listed below and the 5 V reference circuit terminal listed below. Verify the scan tool Engine Oil Pressure Sensor parameter is greater than 4.8 V.
* Terminal 1 and low reference terminal 2, 3.6L engine
* Terminal C and low reference terminal B, 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L engines
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
6. If all circuits test normal, test or replace the engine or pressure 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) for 3.6L engine
* Engine Oil Pressure Sensor and/or Switch Replacement (Service and Repair) for 4.8L, 5.3L, 6.0L, 6.2L or 7.0L engine
* Control Module References (Programming and Relearning) for ECM replacement, setup and programming