GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 Eldorado 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1294

Circuit Description

The stop lamp switch signal informs the electronic brake control module (EBCM) when the brake pedal is pressed.

Conditions for Running the DTC

The vehicle speed is greater than 40 km/h (25 mph).

Conditions for Setting the DTC

The stop lamp switch input was active for 2 consecutive ignition cycles.

Action Taken When the DTC Sets
    • The EBCM disables the TCS for the duration of the ignition cycle.
    • The Traction Control indicator turns ON.
    • The ABS remains functional.

Conditions for Clearing the DTC
    • The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
    • The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
    • The EBCM automatically clears the history DTC when a current DTC is not detected in 50 consecutive drive cycles.

Diagnostic Aids

Possible causes of this DTC are the following conditions:

    • The stop lamp switch circuit is shorted to voltage.
    • The stop lamp switch is misadjusted.
    • The stop lamp switch is stuck closed.
    • A brake pedal that is binding.
    • Both brake light bulbs are burned out.

Test Description

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

  1. Test for the current state of the stoplamp switch parameter.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the ABS Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Brake Light Switch parameter in the Delco/Bosch ABS/TCS ICCS (if equipped) data list.

Does the scan tool display Released?

Go to Step 3

Go to Step 4

3
  1. Press the brake pedal.
  2. With a scan tool, observe the Brake Light Switch parameter.

Does the Brake Light Switch parameter change state?

Go to Diagnostic Aids

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Inspect the stoplamp switch and adjust and/or calibrate if needed. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you find and correct the condition?

Go to Step 11

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the stoplamp switch connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Brake Light Switch parameter.

Does the scan tool display Released?

Go to Step 8

Go to Step 6

6

Test the stoplamp switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

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

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the stoplamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

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

Did you complete the repair?

Go to Step 11

--

10

Replace the stoplamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the repair?

Go to Step 11

--

11
  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