C0161

DTC C0161

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.

DTC Descriptor
DTC C0161 00
- ABS/TCS Brake Switch Circuit

Circuit/System Description

The body control module (BCM) illuminates the stop lamps by applying battery positive voltage to the stop lamp supply voltage circuit. The electronic brake control module (EBCM) receives a voltage input from the stop lamp supply voltage circuit to determine if the brake pedal is applied.

Conditions for Running the DTC

* Ignition ON.
* The vehicle speed is greater than 20 km/h (12 mph).

Conditions for Setting the DTC

* The brake pedal is sensed as applied for 6 minutes.
* The vehicle speed is greater than 20 km/h (12 mph).

* The EBCM does not receive a signal change from the stop lamp supply voltage circuit.
* Vehicle speed exceeds 40 km/h (25 mph) in four cycles, and decelerates to under 3 km/h (2 mph).

Action Taken When the DTC Sets

The ABS remains functional.

Conditions for Clearing the DTC

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

Diagnostic Aids

DTC C0161 can set if the vehicle has been driven with the brake applied during acceleration. Also inspect the brake pedal and sensor for proper operation.

Reference Information
Schematic Reference

* Exterior Lights Schematics Exterior Lights Schematics
* Antilock Brake System Schematics [1][2]Antilock Brakes / Traction Control Systems

Connector End View Reference

Component Connector End Views Connector End Views By Name
Description and Operation

ABS Description and Operation Description and Operation
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 Control Module References for scan tool information

Circuit/System Verification

Note: Diagnose all other stop lamp DTCs or symptoms prior to performing this diagnostic procedure.

1. Verify the brake pedal position sensor or the brake pedal is not binding causing residual brake pressure to be detected, while the brake lights operate properly.

• If a condition is found, repair or replace the applicable component.

2. Apply and release the brake pedal. Verify the brake lights operate properly

• If the brake lights do not operate properly, refer to Symptoms - Lighting Symptoms - Lighting.

3. Ignition On, observe the scan tool EBCM, ABS BPP Signal parameter. The reading should change between Applied and Released while applying and releasing the brake pedal.

• If not within the specified value, refer to Symptoms - Lighting Symptoms - Lighting.

4. Refer to Diagnostic Aids.