GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Impala 🢒 Power and Signal Distribution 🢒 Wiring Systems and Power Management 🢒 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: TCS Brake Switch 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 brake pedal applied state status via high speed GMLAN serial data messages 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

The Ignition is ON.

Conditions for Setting the DTC
    • Brake pedal is sensed as applied during moderate to high vehicle acceleration.
    • Brake pedal state is observed as applied for 144 consecutive seconds.

Action Taken When the DTC Sets
    • EBCM disables the traction control system (TCS) for the duration of the ignition cycle.
    • The vehicle dynamics caution (VDC) indicator turns ON
    • The driver information center (DIC) displays the SERVICE TRACTION CONTROL message

Conditions for Clearing the MIL/DTC
    • The ABS indicator may remain illuminated after repairs are made and DTCs are cleared, until the vehicle is operated at speeds greater than 13 km/h (8 mph) and the self test is completed.
    • 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 during acceleration.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

ABS Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing
  1. With the scan tool, check the vehicle for brake pedal position (BPP) related DTCs.
    2. ⇒If DTC C0277 or C0297 are present, diagnose BPP DTCs.
  2. Lightly apply and release the brake pedal. The stop lamps should illuminate and then turn OFF.
    3. ⇒If the stop lamps do not operate properly, refer to Symptoms - Lighting Systems .
  3. If no Lighting System problems can be found, refer to Diagnostic Aids.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for BCM and EBCM replacement, setup, and programming