Oil Level Sensor: Testing and Inspection
Engine Oil Level Sensor Diagnosis (LS3 )
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
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.
Reference Information
Schematic Reference
* Engine Mechanical Schematics (Diagrams)
* Instrument Cluster Schematics (Instrument Cluster Schematics)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
* Instrument Cluster Description and Operation (Instrument Cluster)
* Indicator/Warning Message Description and Operation (Indicator/Warning Message)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information.
Circuit/System Verification
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.
Circuit/System Testing
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 ohm 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.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Engine Oil Level Sensor and/or Switch Replacement (Service and Repair)
* Engine Control Module Replacement (Service and Repair)
* Instrument Cluster Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for the IPC or ECM replacement, setup, and programming