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.

Circuit/System Description

The engine oil level switch is a normally closed switch that opens when there is a low engine oil level condition. When the switch is open the engine control module (ECM)/powertrain control module (PCM) will detect a high signal voltage input. During a low engine oil level condition the ECM/PCM sends a serial data message to the instrument panel cluster (IPC) requesting display of the LOW OIL LEVEL message in the IPC.

Reference Information

Schematic Reference

    •  Instrument Cluster Schematics
    •  Engine Controls Schematics for the 3.6L engine
    •  Engine Controls Schematics for the 3.8L engine

Connector End View Reference

    •  Displays and Gages Connector End Views
    •  Engine Control Module Connector End Views for the 3.6L engine
    •  Powertrain Control Module Connector End Views for the 3.8L engine

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 engine oil level switch.
  2. Ignition OFF, test for less than 1 ohm of resistance between the ground circuit terminal B and ground.
  3. If greater than 1 ohm, test the ground circuit terminal B for an open/high resistance.
  4. Install a 3-amp fused jumper wire between the signal circuit terminal A and the ground circuit terminal B. Verify the scan tool Engine Oil Level Switch parameter is OK.
  5. If not OK, test the signal circuit terminal A for an open/high resistance. If the circuit tests normal, replace the ECM/PCM.
  6. If all circuits test normal, test or replace the engine oil level switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Engine Oil Level Sensor and/or Switch Replacement for the 3.6L engine
    •  Engine Oil Level Sensor and/or Switch Replacement for the 3.8L engine
    •  Control Module References for ECM/PCM replacement, setup and programming