P0520

DTC P0520

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.

DTC Descriptor

DTC P0520
- Engine Oil Pressure Switch Circuit Malfunction

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The engine oil pressure 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 engine oil pressure switch opens and the ECM should detect a high signal voltage input. When the oil pressure is low, the ECM sends a message via High Speed CAN-Bus to the body control module (BCM). The BCM then sends a message via Low Speed CAN-Bus to the instrument cluster requesting the engine oil pressure indicator turned ON.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

* The ECM detects that the engine oil pressure switch signal circuit is pulled low.

* The above condition is present for greater than 10 seconds.

Action Taken When the DTC Sets

The instrument cluster illuminates the service vehicle soon indicator and the oil pressure low indicator.

Conditions for Clearing the DTC

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

Reference Information

Schematic Reference

Instrument Cluster Schematics Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views Outside Rearview Mirror - Driver

Description and Operation

* Instrument Cluster Description and Operation Instrument Cluster

* Indicator/Warning Message Description and Operation Indicator/Warning Message

* Driver Information Center (DIC) Description and Operation Driver Information Center (DIC)

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

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify the scan tool Engine Oil Pressure parameter is Low.

• If not Low
Refer to Circuit/System Testing.

• If Low

3. Engine running.

4. Verify the scan tool Engine Oil Pressure parameter is OK.

• If not OK
Refer to Circuit/System Testing.

• If OK

5. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B37 engine oil pressure switch, ignition ON.

2. Verify the scan tool Engine Oil Pressure Switch parameter is OK.

• If not OK

1. Ignition OFF, disconnect the harness connector at the K20 engine control module.

2. Test for infinite resistance between the signal circuit terminal 1 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the K20 engine control module.

• If OK

3. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground.

4. Verify the scan tool Engine Oil Pressure Switch parameter is Low.

• If not Low

1. Ignition OFF, disconnect the harness connector at the K20 engine control module, ignition ON.

2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K20 engine control module.

• If Low

5. Test or replace the B37 engine oil pressure switch.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Engine Oil Pressure Switch Replacement Service and Repair

* Control Module References Control Module References for ECM replacement, programming and setup