C0161

DTC C0161
DTC Descriptor
DTC C0161
ABS Brake Switch Circuit

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Diagnostic System Check - Vehicle

Circuit/System Description
The brake switch supplies battery positive voltage to the electronic brake control module (EBCM) when the brake pedal is applied.

Conditions for Running the DTC
Ignition voltage is greater than 9.5 volts.

Conditions for Setting the DTC
Stop switch is on and vehicle speed is greater than 15 km/h (9 mph) for 15 minutes continuously.

Action Taken When the DTC Sets
^ The EBCM disables traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
^ The Stability Caution indicator turns on.
^ The driver information center (DIC) displays the TRACTION FAILED message.

Conditions for Clearing the DTC
^ The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool.
^ The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Reference Information
Schematic Reference
ABS Schematics

Connector End View Reference
ABS Connector End Views

Electrical Information Reference
^ Circuit Testing
^ Connector Repairs
^ Testing for Intermittent Conditions and Poor Connections
^ Wiring Repairs

Scan Tool Reference
Scan Tool Data List

Circuit/System Verification
With the scan tool, observe the Brake Switch Status data parameter. Apply and release the brake pedal. The brake pedal switch status should change from OFF to ON.

Circuit/System Testing
1. Release the brake pedal. With the scan tool observe the Brake Switch Status data parameter.
^ If the fault is current, the scan tool brake switch status displays ON.
^ If the scan tool displays OFF, go to Testing for Intermittent Conditions and Poor Connections. Component Tests and General Diagnostics

2. With the ignition OFF, disconnect the EBCM connector. Connect a test lamp between the stop lamp switch signal circuit and ground.
^ If the test lamp illuminates go to Symptoms - Lighting Systems. Symptoms (Lighting Systems)
^ If the test lamp does not illuminate, replace the EBCM/ brake pressure modulator valve (BPMV) assembly.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

^ Symptoms - Lighting Systems Symptoms (Lighting Systems)
^ Control Module References for EBCM or BPMV replacement, setup, and programming