Document ID: 2808502

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.

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Engine Oil Level Sensor Signal	2	1	—	1
Engine Oil Level Sensor Ground	—	1	—	—
1. DIC message Engine Oil Level Low Always ON 2. DIC message Engine Oil Level Low Always OFF

Typical Scan Tool Data

**Engine Oil Level Switch**
Circuit	Short to Ground	Open	Short to Voltage
Operating Conditions: Ignition ON Parameter Normal Range: OK
Engine Oil Level Sensor/Switch Signal	OK	Low	OK
Engine Oil Level Ground	—	Low	—

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 and a message is displayed on the driver information center.

The following information determines the message sent form the ECM to the instrument cluster. The Engine Oil Level Low message is displayed only after the ECM detects a high voltage on the signal circuit for three consecutive ignition cycles, followed by an ignition OFF event from 15 min to greater than 50 min, depending on the engine oil temperature.

The Engine Oil Level Low message is turned OFF when the ECM detects a low voltage on the signal circuit after an ignition OFF event for greater than 90 s, then followed by the ignition ON for less than 1 s.

Reference Information

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.

Circuit/System Verification

Verify proper engine oil level.

If not at proper level
Add oil as necessary.

If at proper level

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

If not OK
Refer to Circuit/System Testing.

If OK

All OK.

Circuit/System Testing

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

Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B35 Engine Oil Level Switch. It may take up to 2 minutes for all vehicle systems to power down.
Test for less than 5 Ω between the ground circuit terminal 1 and ground.

If 5 Ω or greater

Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
Test for less than 2 Ω in the ground circuit end to end.

If 2 Ω or greater, repair the open/high resistance in the circuit.
If less than 2 Ω, repair the open/high resistance in the ground connection.

If less than 5 Ω

Ignition ON.
Verify the scan tool Engine Oil Level Switch parameter reads Low.

If the Engine Oil Level Switch parameter reads OK

Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
Test for infinite resistance between the signal circuit terminal 2 and ground.

If less than infinite resistance, repair the short to ground on the circuit.
If infinite resistance, replace the K20 Engine Control Module.

If the Engine Oil Level Switch parameter reads Low

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

Install a 3A fused jumper wire between the signal circuit terminal 2 and the ground circuit terminal 1.
Verify the scan tool Engine Oil Level Switch parameter reads OK.

If the Engine Oil Level Switch parameter reads Low

Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.

If 1 V or greater, repair the short to voltage on the circuit.
If less than 1 V

Test for less than 2 Ω in the signal circuit end to end.

If 2 Ω or greater, repair the open/high resistance on the circuit.
If less than 2 Ω, replace the K20 Engine Control Module.

If the Engine Oil Level Switch parameter reads OK

Test or replace the B35 Engine Oil Level Switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Engine Oil Level Sensor and/or Switch Replacement
Control Module References for the ECM replacement, programming, and setup

Oil Level Sensor