GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Holden 🢒 2007 🢒 WM Sedan 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0521

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 P0521: Oil Pressure Sensor Range/Performance

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Engine Oil Pressure 5-Volts Reference Circuit

P0522

P0522

P0523

P0521

Engine Oil Pressure Sensor Signal Circuit

P0522

P0523

P0523

P0521

Low Reference

--

P0523

--

P0521

Circuit/System Description

The engine oil pressure (EOP) sensor changes voltage based on the engine oil pressure. The EOP sensor is a 3-wire sensor comprising of the signal circuit, the low reference circuit and the 5-volt reference circuit. The engine control module (ECM) supplies 5-volts to the EOP sensor via the 5-volt reference circuit and provides ground via the EOP low reference circuit. The ECM monitors the signal circuit of the EOP sensor to determine the engine oil pressure sensor voltage is within the normal operating range of approximately 1-4 volts. When the engine oil pressure is high, the EOP sensor voltage is high and the ECM senses a high signal voltage. When the engine oil pressure is low, the EOP sensor voltage is low and the ECM senses a low signal voltage. The ECM sends the EOP information to the instrument panel cluster (IPC) via GMLAN serial data message.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC
    • The ECM detects that the EOP sensor signal circuit is less not with predetermined parameters.
    • The above condition is present for greater than 10 seconds.

Action Taken when the DTC Sets

DTC P0521 is a type C Store only DTC.

Conditions for Clearing the MIL/DTC

DTC P0521 is a type C Store only DTC.

Reference Information

Schematic Reference

    •  Instrument Cluster Schematics
    •  Engine Controls Schematic Icons

Connector End View Reference

Component Connector End Views

Electrical Information Reference

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

Scan Tool Reference

Control Module References

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the EOP sensor.
  2. Test for less than 1 ohm of resistance between the low reference circuit and a known ground.
    3. ⇒If greater than 1 ohm, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit and a known ground.
    4. ⇒If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit test normal, replace the ECM.
    ⇒If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Connect an approved test lamp between the 5-volt reference circuit and the signal circuit at the wiring harness connection.
    5. ⇒If the test lamp does not illuminate test the signal circuit for a open/high resistance. If the circuit tests normal replace the ECM.
  5. If all circuits test normal, test or replace the EOP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification .

    •  Engine Oil Pressure Sensor and/or Switch Replacement
    •  Control Module References for ECM replacement, setup and programming.