GM Service Manual Online
For 1990-2009 cars only

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 (EOP) Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Oil Pressure Switch Signal

1

P0520

--

--

Low Reference

--

--

--

--

1. Engine Oil Pressure Indicator Always On

Circuit/System Description

The engine control module (ECM)/powertrain control module (PCM) monitors the signal circuit of the engine oil pressure (EOP) sensor. When the oil pressure is high, the sensor is open, and the ECM/PCM senses a high signal voltage. When the oil pressure is low, the sensor is closed, and the ECM/PCM senses a low signal voltage.

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 low.
    • The above condition is present for greater than 5 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.

Diagnostic Aids

Using the Failure Records data may help locate an intermittent condition. If you cannot duplicate the DTC, the information in the Failure Records can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can help determine how many ignition cycles that the diagnostic test reported a pass and/or a fail.

Reference Information

Schematic Reference

    •  Instrument Cluster Schematics
    •  Engine Controls Schematics for the 2.2L engine
    •  Engine Controls Schematics for the 2.4L engine
    •  Engine Controls Schematics for the 3.5L engine

Connector End View Reference

    •  Displays and Gages Connector End Views
    •  Engine Control Module Connector End Views
    •  Powertrain Control Module Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the EOP.
  2. Ignition ON, install a 3-amp fused jumper between the signal circuit and ground. Verify the scan tool Low Oil Pressure Switch parameter is Closed or the scan tool Low Oil Pressure parameter is Yes.
  3. If not Closed or Yes, test the signal circuit of the EOP switch for an open/high resistance. If the circuit tests normal, replace the ECM/PCM.
  4. If all circuits test normal, test or replace the EOP switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 2.2L engine
    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 2.4L engine
    •  Engine Oil Pressure Sensor and/or Switch Replacement for the 3.5L engine
    •  Control Module References for ECM/PCM replacement, setup, and programming