C0161

DTC C0161

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using the 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.

DTC Descriptor
DTC C0161
- ABS/TCS Brake Switch Circuit

Diagnostic Fault Information





Circuit/System Description

The normally-open stop lamp switch supplies battery voltage to the brake lamps when the brake pedal is pressed. The brake lamp switch will also send a signal to the EBCM when the brake pedal is pressed.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

When the vehicle speed exceeds 40 km/h (25 mph) in four cycles and decelerates to under 3 km/h (2 mph) and the EBCM does not receive a voltage signal from the stop lamp switch.

Action Taken When the DTC Sets

The ABS remains functional

Conditions for Clearing the DTC

* The DTC will become history when condition for setting the DTC is no longer present.
* The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Diagnostic Aids

Inspect the brake pedal switch for proper adjustment, refer to Stop Lamp Switch Adjustment (Adjustments)

Reference Information
Schematic Reference

Antilock Brake System Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
* Connector Repairs (Connector Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Observe the function of the brake lights while applying and releasing the brake pedal, the brake lights should turn ON and OFF as the brake pedal is applied and released.

If brake lamps are always ON or always OFF, refer to Symptoms - Vehicle (Symptoms - Vehicle).

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Connect a test lamp between the signal circuit terminal 16 and ground.
3. Ignition ON, apply and release the brake pedal. The test lamp should turn ON and OFF as the brake pedal is applied and released.

• If the test lamp is always ON, test the signal circuit for a short to voltage.

• If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance.

4. If all circuits test normal, replace the EBCM.

Repair Verification

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for EBCM replacement, setup, and programming