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
--- | --- | --- | --- | ---
Engine Oil Pressure Sensor Signal Circuit | -- | P0520 | P0520 | --
Engine Oil Pressure Sensor Ground Circuit | -- | P0520 | -- | --

### 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 circuit with the ignition switch turned ON, and the engine turned OFF. When the oil pressure is low, the ECM/PCM sends a serial data message to the body control module (BCM) requesting the EOP indicator turned ON. The 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

The ignition is ON, with the engine ON.

### Conditions for Setting the DTC

• | The ECM/PCM detects that the EOP sensor signal circuit is pulled high.

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

### Action Taken When the DTC Sets

• | The ECM/PCM records the operating conditions at the time the diagnostic test fails. The ECM/PCM displays this information in the Failure Records on the scan tool.

• | The instrument panel cluster (IPC) illuminates the engine oil pressure indicator.

### 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.

• | The ECM/PCM receives a clear code command from the scan tool.

### Reference Information

#### Schematic Reference

• | Instrument Cluster Schematics

• | Engine Controls Schematics for the 2.0L engine

• | Engine Controls Schematics for the 2.2L engine

• | Engine Controls Schematics for the 2.4L engine

#### Connector End View Reference

• | Powertrain Control Module Connector End Views

• | Powertrain Control Module Connector End Views for the 2.0L engine

• | Engine Control Module Connector End Views for the 2.2L engine

• | Engine Control Module Connector End Views for the 2.4L engine

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Scan Tool Data List

### Circuit/System Testing

Important: Do not turn the key to the crank position or engage the starter at any time during diagnosis.

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

⇒ | If greater than 1 ohm, test the ground circuit for an open/high resistance.

3. Ignition ON, install a 3-Amp fused jumper wire between the EOP switch signal circuit terminal A and ground. Verify the scan tool Engine Oil Pressure Switch parameter is Low.

⇒ | If not Low, test the signal circuit of the EOP switch for a short to voltage or an open/high resistance. If circuit test normal, replace the ECM/PCM.

4. If all circuits test normal, 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 2.0L engine

• | Engine Oil Pressure Sensor and/or Switch Replacement for the 2.2L engine

• | Engine Oil Pressure Sensor and/or Switch Replacement for the 2.4L engine

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