C0161
DTC C0161
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptor
DTC C0161
- ABS Brake Switch Circuit
Diagnostic Fault Information
Circuit/System Description
The brake switch supplies B+ 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
* EBCM disables traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
* A DIC message and/or a warning indicator may be displayed.
Conditions for Clearing the DTC
* The condition for setting the DTC is no longer present.
* The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Reference Information
Schematic Reference
Antilock Brake System Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
ABS Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information.
Circuit/System Verification
1. Ignition ON, use a scan tool to observe the EBCM Brake Switch Status parameter while applying and releasing the brake pedal. The reading should change between ON and OFF.
2. Verify the stop lamp switch is properly adjusted, refer to Stop Lamp Switch Adjustment (Adjustments)
Circuit/System Testing
Important: It is recommend that the defective components be replaced, and not the complete brake master cylinder assembly.
1. Ignition OFF, disconnect the harness connector at the stop lamp switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ terminal 1 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the signal circuit terminal 2 for a short to ground.
3. Verify the EBCM Brake Switch Status parameter displays OFF.
• If not the specified value, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the EBCM.
4. Install a 3A fused jumper wire between the B+ circuit terminal 1 and signal circuit terminal 2. Verify the scan tool EBCM Brake Switch Status is ON.
• If not the specified value, test the signal circuit for a short to ground 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 harness connector at the stop lamp switch.
2. Test for infinite resistance between the B+ terminal 1 and the signal terminal 2 with the switch in the open position.
• If not the specified value, replace the stop lamp switch.
3. Test for less than 1.0 ohm between the B+ terminal 1 and the signal terminal 2 with the switch in the closed position.
• If greater than the specified range, replace the stop lamp switch.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Stop Lamp Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for EBCM or BPMV replacement, setup, and programming