GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 DeVille 🢒 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.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C1294 Brake Lamp Switch Circuit Always Active

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 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

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 stop lamp switch parameter.

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 in Vehicle DTC Information

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Stop Lamp Switch parameter in the DRP/ABS/TCS 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 Stop Lamp Switch parameter.

Does the Stop Lamp Switch parameter change state?

Go to Diagnostic Aids

Go to Step 4

4
  1. Turn OFF the ignition.
  2. Inspect the stop lamp switch and adjust and/or calibrate if needed. Refer to Stop Lamp Switch Replacement in Lighting Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Disconnect the stop lamp switch connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Stop Lamp Switch parameter.

Does the scan tool display Released?

Go to Step 8

Go to Step 6

6

Test the stop lamp 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 electronic brake control module (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 stop lamp 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 Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

10

Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Lighting Systems.

Did you complete the replacement?

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