Engine Oil Level Sensor Diagnosis w/LS3 or LS7

The engine oil level sensor/switch is a normally-closed with proper engine oil level. The switch opens when the engine oil level drops below a calibrated level. The engine control module (ECM) monitors the engine oil level signal circuit when the ignition is ON, and the engine is OFF. With the switch in the closed position, the ECM detects a low voltage signal circuit. With the switch in the open position, the ECM detects a high voltage on the signal circuit. When high voltage is detected on the signal circuit, the ECM will send a serial data message to the instrument panel cluster (IPC) and a message is displayed on the driver information center (DIC).

The oil level low message is displayed only after the ECM detects a high voltage on the signal circuit, followed by an ignition OFF event greater than 30 minutes, followed again by the detection of high voltage on the signal circuit when the ignition is turned to the ON position.

The oil level low message is turned OFF when the ECM detects a low voltage on the signal circuit and after an ignition OFF event for greater than 90 seconds, followed by the detection of low voltage on the signal circuit when the ignition has been turned to the ON position for less than 1 second.

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information.

1. Verify proper engine oil level. Add oil as necessary.
2. Ignition ON, observe the scan tool Engine Oil Level parameter. The reading should be OK and change to Low when the oil level sensor/switch harness connector is disconnected.

Note: Verify proper engine oil level before continuing with diagnosis.

1. Ignition OFF, disconnect the harness connector at the engine oil level sensor.
2. Ignition OFF for 90 seconds, test for less than 1 Ω between the low reference circuit terminal C and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the IPC.

3. Ignition ON, verify the scan tool Engine Oil Level parameter reads Low.

⇒	If the Oil Level parameter reads OK, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the ECM.

Important: If a short to voltage is found on the signal circuit, the fuse in the 3A jumper wire will open.

4. Ignition ON, install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal C. Verify the scan tool Engine Oil Level parameter reads OK.

⇒	If the Engine Oil Level parameter reads Low, test the signal circuit terminal A for an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the engine oil level sensor and/or switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Engine Oil Level Sensor Diagnosis w/LS9

The engine oil level sensor is a normally-closed switch that opens when engine oil level drops below a calibrated level. In the closed position, the low reference circuit of the oil level sensor produces a low voltage on the oil level sensor signal at the ECM. With a low engine oil level, the switch opens producing a high voltage on the oil level sensor signal at the ECM. When the ECM detects high voltage on the oil level sensor signal, the ECM will illuminate the Low Engine Oil indicator or cause a Check Engine Oil message to be displayed on the driver information center (DIC).

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information.

Note: Verify proper engine oil level before continuing with diagnosis.

1. Ignition OFF, disconnect the harness connector at the engine oil level sensor.
2. Ignition OFF, test for less than 1 Ω between the low reference circuit terminal C and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

3. Ignition ON, verify the scan tool Engine Oil Level parameter reads Low.

⇒	If the Oil Level parameter reads OK, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the IPC.

4. Ignition ON, install a 3A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal C. Verify the scan tool Engine Oil Level parameter reads OK.

⇒	If the Engine Oil Level parameter reads Low, test the signal circuit terminal A for an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the engine oil level sensor and/or switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.