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Engine Oil Pressure Indicator Malfunction - DTC P0520

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.

The engine is running.

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

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

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Vehicle in Service Mode, 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.

1. Vehicle OFF, disconnect the harness connector at the B37 engine oil pressure switch.
2. Vehicle in Service Mode, verify the scan tool ECM - Engine Oil Pressure Switch parameter is OK.

⇒	If not the specified value, test for the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the K20 ECM.

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

⇒	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 the K20 ECM.

4. Command the All Indicators test ON and OFF with the scan tool. The engine oil pressure indicator should turn ON and OFF when changing between the commanded states.

⇒	If the engine oil pressure indicator always on or always off, replace the P16 instrument cluster.

5. If all circuits test normal, test or replace the B37 engine oil pressure switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.