C0161

DTC C0161

DTC Descriptor

DTC C0161 00

Antilock Brake System (ABS) Brake Switch/Sensor Circuit not Plausible.

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description

The brake pedal position (BPP) sensor is an input to the body control module (BCM). The BCM then sends a GMLAN serial data message 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.

Conditions for Running the DTC

^ The ignition is ON.
^ The vehicle speed is greater than 16 km/h (10 mph).
^ The ignition voltage is greater than 9.5 volts.

Conditions for Setting the DTC

^ The GMLAN signal for the brake switch indicates the switch is always on.
^ The GMLAN signal for the brake switch indicates the switch is always off.

Action Taken When the DTC Sets

The ABS/TCS/VSES if equipped, remains functional.

Conditions for Clearing the DTC

^ The condition for 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.

Diagnostic Aids

The DTC C0161 00 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

Antilock Brake System Connector End Views

Description and Operation Reference

ABS Description and Operation (Under 8600 GVW ) ABS Description and Operation (Equal to or Over 8600 GVW)

Electrical Information Reference

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

Scan Tool Reference

Scan Tool Data List for EBCM

Circuit/System Verification

With the ignition ON, use a scan tool to display DTCs for the BCM.

If DTC B3445 is present, Refer to Diagnostic System Check - Vehicle.
If no DTCs are present, go to Diagnostic Aids. Initial Inspection and Diagnostic Overview

Circuit/System Testing

Apply and release brake pedal. Verify brake lamps operate properly. If brake lamps do not operate properly, review brake pedal position sensor diagnostics in lighting. Refer to Symptoms - Lighting Systems. - Symptoms - Lighting

Repair Verification

Diagnostic Repair Verification