For 1990-2009 cars

### 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.

### DTC Descriptor

DTC P0520: Engine Oil Pressure (EOP) Sensor Circuit

### 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. Engine Oil Pressure Indicator Malfunction

### Circuit 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.

### Conditions for Running the DTC

• | DTC P0117 is not set.

• | DTC P0118 is not set.

• | DTC P1111 is not set.

• | DTC P1114 is not set.

• | The ignition is ON, with the engine OFF.

• | Engine temperature at the last shutdown was at least 80°C (176°F).

### Conditions for Setting the DTC

• | The ECM detects that the oil pressure switch signal circuit is high.

• | The above condition is present for greater than 10 seconds.

### Action Taken When the DTC Sets

The ECM stores the conditions that are present when the DTC sets. This information is stored as Failure Records data only. This information is not stored as Freeze Frame data.

### Conditions for Clearing the DTC

• | The DTC becomes history when the conditions for setting the DTC are no longer present.

• | The history DTC clears after 40 malfunction-free warm-up cycles.

### Reference Information

#### Schematic Reference

Instrument Cluster Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

• | Indicator/Warning Message Description and Operation

• | Instrument Cluster Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### 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 to Oil Pressure Diagnosis and Testing for the 2.9L engine, or Oil Pressure Diagnosis and Testing for the 3.7L engine.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the engine oil pressure (EOP) switch.
2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal B and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify the scan tool Engine Oil Pressure Switch parameter is OK.

⇒ | If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.

4. Ignition ON, install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B. Verify the scan tool Engine Oil Pressure Switch parameter is Low.

⇒ | If not the specified value, test the signal circuit for an open/high resistance. If circuit test normal, replace the ECM.

5. If all circuits test normal, test or replace the engine oil pressure switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Engine Oil Pressure Sensor and/or Switch Replacement for the 2.9L engine

• | Engine Oil Pressure Sensor and/or Switch Replacement for the 3.7L engine

• | Control Module References for the ECM replacement, setup, and programming