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DTC P0520

DTC P0520

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 Switch Circuit Malfunction

Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performance
Signal 1 P0520 1 -
Low Reference - P0520 - -
1. Engine Oil Pressure Indicator Malfunction


Typical Scan Tool Data

ECM - Engine Oil Pressure Switch

Circuit Short to Ground Open Short to Voltage
Operating Conditions: Engine Running Parameter Normal Range: OK
Signal Low OK OK
Low Reference - OK -


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

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

Connector End View Reference

Component Connector End Views

Description and Operation


• Instrument Cluster Description and Operation

• Indicator/Warning Message Description and Operation

• Driver Information Center (DIC) Description and Operation


Electrical Information Reference


• Circuit Testing

• Connector Repairs

• Testing for Intermittent Conditions and Poor Connections

• Wiring Repairs


DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Engine Oil Pressure Switch parameter. With the ignition switch turned ON and the engine not running the reading should be Low, with the engine running the reading should be OK.

Circuit/System Testing


1. Ignition OFF, disconnect the harness connector at the B37 Engine Oil Pressure Switch.

2. If applicable, test for less than 30 Ω between the low reference circuit terminal B and ground.

3. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace K20 Engine Control Module.

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

5. If not the specified value, test for the signal circuit terminal A for a short to ground. If the circuit tests normal, replace K20 Engine Control Module.

6. Install a 3 A fused jumper wire between the signal circuit terminal A and ground . Verify the scan tool Engine Oil Pressure Switch parameter is Low.

7. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace K20 Engine Control Module.

8. If all circuits test normal, test or replace the B37 Engine Oil Pressure Switch.


Component Testing


Static Test

1. Ignition OFF, disconnect the harness connector at the B37 Engine Oil Pressure Switch.

2. Test for infinite resistance between the signal terminal A and the low reference terminal B with the switch in the open position.

3. If not the specified value, replace the B37 Engine Oil Pressure Switch.

4. Test for less than 5 Ω between the signal terminal A and the low reference terminal B with the switch in the closed position.

5. If greater than the specified range, replace the B37 Engine Oil Pressure Switch.


Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.


• Engine Oil Pressure Sensor and/or Switch Replacement (LAU) Engine Oil Pressure Sensor and/or Switch Replacement (LF1 or LFW)

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