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 Descriptors

DTC C0161 00
- Antilock Braking System Brake Sensor Circuit

DTC C0161 5A
- Antilock Braking System Brake Sensor Signal Not Plausible

Circuit/System Description

When the brake pedal is applied, the Body Control Module sends a serial data message to the Electronic Brake Control Module in reference to the brake pedal position. The Electronic Brake Control Module compares the correlation between the brake pedal position and the amount of brake pressure it senses from the Brake Pressure Sensor, which is internal to the Brake Pressure Modulator. It uses this information to control the vehicle during a stability control event.

Conditions for Running the DTC

* Ignition ON

* DTC C0131 is not present.

Conditions for Setting the DTC

C0161 00

* The Brake Pedal Position Sensor data is invalid.

* The Electronic Brake Control Module detects serial data fault.

* A reprogrammed Body Control Module will set this DTC if the Brake Pedal Position Sensor is not learned (Perform the BCM Brake Pedal Position Sensor Learn).

C0161 5A

* The Electronic Brake Control Module detects that the brake pedal is permanently applied; or the Body Control Module sends a serial data message that the brake is applied, the brake pressure is less than 483 kPa (70 psi), the vehicle speed is greater than 11 km/h (7 MPH), and the accelerator pedal is greater than 10% for 60 seconds.

* The Brake Pedal Position Sensor Signal is not plausible with the brake pressure sensor; or the brake is not applied and the brake pressure is greater than 1034 kPa (150 psi) for 1 second.

Action Taken When the DTC Sets

* The Stability Control indicator turns ON.

* The Traction Control Off indicator turns ON.

* The Stability Control Off indicator turns ON.

* The Electronic Brake Control Module disables the traction control and electronic stability control for the duration of the ignition cycle.

Conditions for Clearing the DTC

* When the condition for setting the DTC is no longer present.

* The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.

Note: During normal diagnostic and/or repair verification technicians may find that the ABS, Traction/stability Control indicators may be ON with NO DTCs displayed by the Electronic Brake Control Module. Do not replace the Electronic Brake Control Module for this condition.

If the ABS, Traction/stability Control indicators are ON with no DTCs set, perform the following steps:

1. Remove the key from the ignition, open and close the driver's door to turn off retained accessory power, and wait 60 seconds.

2. Ignition ON, if the ABS, Traction/stability Control indicators are still illuminated, operate the vehicle at speeds greater than 16 km/h (10 MPH) to complete the self test. The Electronic Brake Control Module should request all indicators to turn OFF.

3. If indicators remain ON with no DTCs set after the drive cycle, disconnect the battery for at least 60 seconds then reconnect the battery.

4. Operate the vehicle at speeds greater than 40 km/h (25 MPH), the Electronic Brake Control Module Should request all the indicators to turn OFF.

Reference Information

Schematic Reference

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

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly

Description and Operation

ABS Description and Operation (Without F55) ABS Description and Operation (Without F55)ABS Description and Operation (With F55) ABS Description and Operation (With F55)

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

Circuit/System Verification

Note: A reprogrammed Body Control Module will set this DTC if the Brake Pedal Position Sensor is not learned (Perform the BCM Brake Pedal Position Sensor Learn).

1. Ignition ON.

2. Verify the Body Control Module Brake Pedal Position Sensor Learned Released Position parameter is Yes.

• If the parameter is not Yes.
Refer to Brake Pedal Position Sensor Calibration Brake Pedal Position Sensor Calibration.

• If the parameter is Yes

3. Verify that DTC C0277 or C0278 is not set.

• If either DTC is set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.

• If either DTC is not set

4. Verify the Brake Pedal Position Sensor or the brake pedal are not binding causing residual brake pressure to be detected.

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

• If a condition is not found

5. Verify the scan tool Electronic Brake Control Module Brake Pedal Position Sensor parameter changes between Active and Inactive when applying and releasing the brake pedal.

• If the parameter does not change
Refer to Symptoms - Lighting Symptoms - Lighting.

• If the parameter changes

6. Replace the Q5 Brake Pressure Modulator.

7. Verify the DTC does not set while operating the vehicle within the Conditions for Running the DTC.

• If the DTC sets
Replace the K17 Electronic Brake Control Module.

• If the DTC does not set

8. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Brake Pressure Modulator Valve Replacement Service and Repair

* Control Module References Control Module References for Electronic Brake Control Module replacement, programming and setup