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 |
|---|---|---|---|---|
Engine Oil Pressure Switch Signal Circuit | 1 | P0520 | P0520 | -- |
Engine Oil Pressure Sensor Ground Circuit | -- | P0520 | -- | -- |
1. Engine Oil Pressure Indicator Always On | ||||
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)/powertrain control module (PCM) should detect a low signal voltage input. With the engine running, the pressure switch opens, and the ECM/PCM should detect a high signal voltage input. The ECM/PCM tests the state of the EOP signal circuit with the ignition switch turned ON, and the engine turned OFF. The instrument panel cluster (IPC) illuminates the EOP indicator when the IPC receives a serial data message from the ECM/PCM requesting the EOP indicator turned ON.
Reference Information
Schematic Reference
Connector End View Reference
| • | Engine Controls Connector End Views for the 4.6L engine |
| • | Powertrain Control Module Connector End Views for the 3.8L engine |
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
Important: Do not turn the key to the crank position or engage the starter at any time during diagnosis.
- Ignition ON, verify the scan tool Engine Oil Pressure (EOP) Switch parameter is Low.
- Ignition OFF, disconnect the EOP switch.
- Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.
| ⇒ | If not Low, replace the instrument panel cluster (IPC). |
| ⇒ | If not OK, test the oil pressure switch signal terminal A for a short to ground. If the circuit tests normal, replace the ECM/PCM. |
| ⇒ | If OK, test or replace the EOP switch. |
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 3.8L engine |
| • | Control Module References for the ECM/PCM or IPC replacement, setup and programming |
