GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 HUMMER 🢒 2008 🢒 H2 🢒 DTC 🢒 DTC C0161

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 71: ABS/TCS Brake Switch Sensor Circuit Invalid Serial Data Received

Circuit/System Description

The brake switch supplies battery positive voltage to the body control module (BCM) when the brake pedal is applied. The brake signal input status is communicated to the EBCM over the serial data network.

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
    • EBCM disables traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
    • Stability Caution indicator turns ON.
    • Driver information center (DIC) displays the TRACTION FAILED message.
    • An ECE 13 response occurs.

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

Antilock Brake System Schematics

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

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.
    2. ⇒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 .
  2. With the ignition OFF, disconnect the BCM connector. With the Ignition ON release the brake pedal and connect a test lamp between the stop lamp switch signal circuit and ground.
    3. ⇒If the test lamp illuminates go to Symptoms - Lighting Systems .
    ⇒If the test lamp does not illuminate, replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM replacement, setup, and programming