W/JL4

DTC C0161 (W/JL4)

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.



DTC Descriptor
DTC C0161 00
- ABS Brake Switch Circuit

DTC C0161 11
- ABS/TCS Brake Switch Circuit Above Maximum Threshold

DTC C0161 12
- ABS/TCS Brake Switch Circuit Below Maximum Threshold

DTC C0161 71
- ABS/TCS Brake Switch Sensor Circuit Invalid Serial Data Received




Diagnostic Fault Information






Circuit/System Description

The brake switch informs the electronic brake control module (EBCM) when the brake is depressed. The brake switch is normally closed supplying 12 volts to the EBCM when the brake is released. When the brake pedal is pressed, voltage on the torque converter clutch (TCC) brake switch signal circuit is 0 volts.


Conditions for Running the DTC

* The vehicle accelerates from 0 km/h (0 mph) to a speed greater than 56 km/h (35 mph).
* The vehicle experiences an ABS event involving all hydraulic circuits.
* The EBCM detects that the master cylinder pressure is greater than 400 kPa (200 psi) and that the vehicle is decelerating.



Conditions for Setting the DTC

Any of the following conditions may cause the DTC to set:

* Voltage on the TCC brake switch signal circuit is always low.
* Voltage on the TCC brake switch signal circuit is always high.
* Voltage on the TCC brake switch signal circuit is high for 0.54 seconds when voltage is expected to be low.



Action Taken When the DTC Sets

* The EBCM disables the vehicle stability enhancement (VSES).
* The TCS operates with engine torque reduction capability only.
* The stability indicator turns ON.



Conditions for Clearing the DTC

The conditions for setting the DTC are no longer present.


Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Electrical Information Reference.


Reference Information
Connector End View Reference

Component Connector End Views
Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information


Circuit/System Verification

Ignition ON, observe the scan tool EBCM brake pedal position (BPP) sensor Data Display parameter. The brake pressure position scan tool status reading should read Released and change to Applied with the applying of the brake.


Circuit/System Testing

1. Ignition OFF, disconnect the stop lamp harness connector at the stop lamp switch.
2. Test for less than 1.0 ohm between the ground circuit terminal A and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool EBCM brake pedal position sensor data parameter is Released.

• If not the specified value, test the signal circuit terminal D for a short to ground. If the circuit tests normal, replace the EBCM.

4. Install a 3A fused jumper wire between the signal circuit terminal D and the ground circuit terminal A. Verify the scan tool EBCM brake pedal positionparameter is OFF.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the EBCM.

5. If all circuits test normal, test or replace the stop lamp switch.



Component Testing

1. Ignition OFF, disconnect the stop lamp switch harness connector at the stop lamp switch.
2. Test for 0-2 ohms of resistance between the signal terminal D and the low reference circuit terminal A.

• If not within the specified range, replace the stop lamp switch.

3. Test for infinite resistance between each terminal and the sensor housing/case.

• If less than the specified value, replace the stop lamp switch.




Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Stop Lamp Switch Replacement
* Control Module References for EBCM replacement, setup, and programming