P0520

DTC P0520

Diagnostic Instructions
^ Perform the [Diagnostic System Check - Vehicle Diagnostic Information] prior to using this diagnostic procedure. Diagnostic System Check - Vehicle Diagnostic Information
^ Review [Strategy Based Diagnosis] for an overview of the diagnostic approach. Strategy Based Diagnosis
^ [Diagnostic Procedure Instructions - Vehicle Diagnostic Information] provides an overview of each diagnostic category. Diagnostic Procedure Instructions - Vehicle Diagnostic Information

DTC Descriptor

DTC P0520 Engine Oil Pressure (EOP) Switch Circuit

Diagnostic Fault Information






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) 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. The ECM 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 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
The engine is running.

Conditions for Setting the DTC
^ The ECM detects that the EOP sensor signal circuit is pulled low.
^ The above condition is present for greater than 5 seconds.

Action Taken When the DTC Sets
^ The ECM records the operating conditions at the time the diagnostic test fails. The ECM 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.

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].

Circuit/System Testing

NOTE: 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 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 - Vehicle Diagnostic Information] after completing the diagnostic procedure. Diagnostic Repair Verification - Vehicle Diagnostic Information
^ [Engine Oil Pressure Sensor and/or Switch Replacement]
^ [Control Module References] for ECM replacement, setup, and programming Programming and Relearning