DTC Descriptor
DTC P0520 : Engine Oil Pressure (EOP) Sensor CircuitDiagnostic Fault Information
Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Engine Oil Pressure Sensor Signal Circuit | 1 | P0520 | P0520 | -- |
Engine Oil Pressure Sensor Ground Circuit | -- | P0520 | -- | -- |
1. Engine Oil Pressure Indicator Always On | ||||
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)/powertrain control module (PCM) should detect a low signal voltage input. With the engine running, the oil pressure switch opens, and the ECM/PCM detects a high signal voltage input. The ECM/PCM tests the state of the EOP signal circuit with the ignition switch turned ON, and the engine turned OFF. When the oil pressure is low, the ECM/PCM sends a GMLAN 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 ignition is ON, with the engine ON.
Conditions for Setting the DTC
| • | The ECM/PCM detects that the EOP sensor signal circuit is pulled high. |
| • | The above condition is present for greater than 10 seconds. |
Action Taken When the DTC Sets
| • | The ECM/PCM records the operating conditions at the time the diagnostic test fails. The ECM/PCM 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. |
| • | The ECM/PCM receives a clear code command from the scan tool. |
Reference Information
Schematic Reference
| • | Engine Controls Schematics for the 4.6L engine |
| • | Engine Controls Schematics for the 3.8L engine |
Connector End View Reference
| • | Engine Controls Connector End Views for the 4.6L engine |
| • | Powertrain Control Module Connector End Views for the 3.8L engine |
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
Important: Do not turn the key to the crank position or engage the starter at any time during diagnosis.
- Ignition OFF, disconnect the engine oil pressure (EOP) switch connector.
- Ignition OFF, test for less than 1 ohm of resistance between the ground circuit and ground.
- Ignition ON, install a 3-Amp fused jumper wire between the signal circuit of the EOP switch and ground. Verify the scan tool Engine Oil Pressure Switch parameter is Low.
- If all circuits test normal, replace the engine oil pressure switch.
| ⇒ | If greater than 1 ohm, test the ground circuit for an open/high resistance. |
| ⇒ | If not Low, test the signal circuit of the EOP switch for a short to voltage or an open/high resistance. If circuit test normal, replace the ECM. |
Repair Instructions
Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 4.6L engine |
| • | Engine Oil Pressure Sensor and/or Switch Replacement for the 3.8L engine |
| • | Control Module References for the ECM replacement, setup, and programming |
