Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Oil Pressure Switch Signal | 1 | P0520 | 1 | -- |
Low Reference | -- | P0520 | 1 | -- |
1. Engine Oil Pressure Indicator Malfunction | ||||
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
Connector End View Reference
Description and Operation
Instrument Cluster Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, engine running, verify the scan tool Engine Oil Pressure Switch parameter is OK.
| ⇒ | If not the specified value, refer: |
| • | Oil Pressure Diagnosis and Testing for the 4.6L engine. |
| • | Oil Pressure Diagnosis and Testing for the 3.9L engine. |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the engine oil pressure (EOP) switch.
- Ignition OFF, test for less than 1 ohm between the ground circuit terminal B and ground.
- Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.
- Ignition ON, install a 3A 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 all circuits test normal, test or replace the engine oil pressure switch.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM. |
| ⇒ | If not the specified value, test the signal circuit for an open/high resistance. If circuit test normal, replace the ECM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 4.6L engine |
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 3.9L engine |
| • | Control Module References for the ECM and IPC replacement, setup, and programming |
