GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

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.

Diagnostic Aids

The low engine oil level indicator is also used as the change engine oil indicator. When the indicator is flashing a low engine oil level condition is present and when solid and not flashing the engine oil needs to be changed.

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

    •  Instrument Panel, Gages, and Console 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

    •  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