C0161

DTC C0161

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC C0161
- Antilock Brake System (ABS)/Traction Control System (TCS) Brake Sensor Circuit




Circuit/System Description

The brake pedal position (BPP) sensor is an input to the body control module (BCM). The BCM activates the brake lamps when the BPP is in an applied state. The BCM then sends a serial data message to the electronic brake control module (EBCM) and other electronic control modules. The BPP sensor is a potentiometer type sensor with a 5-volt reference circuit and a low reference circuit. The BCM supplies the 5-volt reference to the BPP.


Conditions for Running the DTC

Engine Running and the vehicle is moving.


Conditions for Setting the DTC

* EBCM detects the brake pedal is applied from the brake pressure sensor reading, and the BPP signal is not detected for 5 seconds when the vehicle is stopping, or when the brake pressure sensor reading indicates the brake pedal is not applied and BPP signal is detected for 144 seconds when driving.
* No brake pressure faults are detected.



Action Taken When the DTC Sets

* EBCM disables the traction control system (TCS) and stability control for the duration of the ignition cycle.
* The traction control warning indicator and the stability control warning indicator turns ON.



Conditions for Clearing the DTC

* The warning indicators may remain illuminated after repairs are made until the DTCs are cleared, and the vehicle is operated at speeds greater than 13 km/h (8 mph) for the self test to complete.
* The condition for setting the DTC is no longer present.
* The EBCM will clear a history DTC when a malfunction is not detected in 100 consecutive drive cycles.



Diagnostic Aids

The DTC C0161 can be set if the vehicle has been driven with the brake applied when driving.


Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

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


Circuit/System Verification

1. Ignition ON, observe the EBCM scan tool BPP Signal parameter. The reading should be Released when the pedal is not pressed, and Applied when pressed.
2. Verify DTC C0277 or C0278 is not set.

• If either of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).

3. Replace the EBCM.



Repair Instructions

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


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