GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2006 🢒 GTO 🢒 DTC 🢒 DTC C0161

Circuit Description

The electronic brake control module (EBCM) monitors brake pedal position through the stop lamp switch. The stop lamp switch is closed when the brake pedal is pressed and the stop lamp switch opens when the brake pedal is released. When the stop lamp switch is closed, the EBCM receives a voltage signal from the stop lamp switch.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0161 Brake Switch Circuit Malfunction

Conditions for Running the DTC

DTC C0161 can be set anytime the ignition switch is ON.

Conditions for Setting the DTC

The EBCM detects an open, high resistance or short to ground in the stop lamp switch signal circuit.

Action Taken When the DTC Sets
    • The EBCM stores this information only for as long as the condition is present.
    • The ABS/TCS remains functional.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • Misadjusted stop lamp switch
    • Faulty stop lamp switch
    • Open, high resistance or short to ground in the stop lamp switch signal circuit
    • An internal EBCM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step test the EBCM stop lamp signal circuit for an open, high resistance or short to ground.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Check stop lamp operation.

Do the stop lamps operate properly?

Go to Step 3

Go to Symptoms - Lighting Systems

3
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Brake Switch parameter in the ABS Data list.
  4. Press the brake pedal while observing the brake switch parameter.

Does the scan tool display applied?

Go to Step 4

Go to Step 5

4
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 5

Go to Diagnostic Aids

5

Test the electronic brake control module (EBCM) stop lamp signal circuit for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 8

Go to Step 6

6

Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 8

Go to Step 7

7

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

Go to Step 8

--

8
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK