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 Descriptors
DTC P0520
- Engine Oil Pressure Switch Circuit
Diagnostic Fault Information
Circuit/System Description
The engine oil pressure switch is a two wire switch that opens and closes based on engine oil pressure. The engine control module (ECM) supplies a 12 volt signal to the switch. The switch also has a ground. The ECM monitors the signal circuit to determine if the switch is opened or closed. When the engine oil pressure is low, the switch is closed and voltage on the signal circuit is low. When the engine oil pressure is normal, the switch is closed and voltage on the signal circuit is high. The ECM sends the engine oil pressure information via serial data to the body control module (BCM). The BCM then sends the engine oil pressure information to the instrument cluster via serial data. The instrument cluster will illuminate the oil pressure indicator when engine oil pressure is low.
Conditions for Running the DTC
The engine is running
Conditions for Setting the DTC
The ECM detects low oil pressure when the engine is running
Action Taken When the DTC Sets
The instrument cluster illuminates the oil pressure indicator.
Conditions for Clearing the DTC
The DTC becomes history when the conditions for setting the DTC are no longer present.
Diagnostic Aids
Low engine oil pressure will also cause this DTC to set. If low engine oil pressure is suspected, refer to Oil Pressure Diagnosis and Testing Oil Pressure Diagnosis and Testing.
Reference Information
Schematic Reference
Instrument Cluster Schematics Instrument Cluster Schematics
Connector End View Reference
Component Connector End Views Fuel Pump and Level Sensor Assembly
Description and Operation
Instrument Cluster Description and Operation Instrument Cluster
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
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
With UDD
1. Ignition ON.
2. Verify the engine oil pressure indicator turns on & off when commanding the All Indicators ON and OFF with a scan tool.
• If the engine oil pressure indicator does not turn on and off.
Replace the P16 instrument cluster.
• If the engine oil pressure indicator turns on and off
3. Verify the scan tool Engine Oil Pressure parameter is Low.
• If not Low
Refer to Circuit/System Testing.
• If Low
4. Engine running.
5. Verify the scan tool Engine Oil Pressure parameter is OK.
• If not OK
Refer to Circuit/System Testing.
• If OK
6. All OK.
With UDV
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 and all vehicle systems OFF, disconnect the harness connector at the B37 Engine Oil Pressure Switch. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal B and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Verify the scan tool Engine Oil Pressure 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 A 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
5. Install a 3 A fused jumper wire between the signal circuit terminal A and the ground circuit terminal B.
6. Verify the scan tool Engine Oil Pressure 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
7. 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 Sensor and/or Switch Replacement Service and Repair
* Control Module References Control Module References for Instrument Cluster or Engine Control Module replacement, programming, and setup