C0161

DTC C0161 ABS Brake Switch Circuit Malfunction

Steps 1-14 (continue):

Steps 14 (continued) & 15:

Circuit Description
When the brake pedal is depressed, the contacts on the brake light switch close to illuminate the brake lights. Battery voltage is also applied to terminal 14 of the Electronic Brake Control Module (EBCM), which signals the ABS controller that the brakes are applied and ABS may be needed. Without this, signals from a wheel speed sensor that may indicate need for ABS intervention are questionable. When the brake pedal is not depressed, the EBCM terminal 14 is grounded through the brake lights.

Diagnosis
This procedure will check whether there is no output or constant output from the brake light switch and will determine the cause as a faulty switch or a problem in the circuitry.

Cause(s)
- The ground connection or the positive connection at the EBCM has failed.
- There is an open, short to ground, or short to positive in the vehicle wiring. The brake light switch has failed.

Fail Action
The system records a DTC C0161. ABS and EBD operation is enabled and ABS / EBD warning lamp don't turn on.

Test Description
The number(s) refer to step(s) on the diagnostic table.
1. This simple test will isolate the problem to the fuse-brake light switch-splice 301 area or the splice 301-EBCM area.
3. This is the first step in identifying an open, a short to ground, a short to voltage, or a faulty brake light switch.
11. This step begins the process of finding an open, a defective connector, or a faulty EBCM.

Diagnostic Aids
Inspect wiring and connectors carefully and thoroughly. Failure to do so could result in misdiagnosis, causing part replacement with reappearance of the malfunction.