GM Service Manual Online
For 1990-2009 cars only

Object Number: 155212  Size: SF
ABS Components
Antilock Brake System Schematics
Power Distribution Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice
Exterior Lights Schematics

Circuit Description

DTC C1295 identifies open brake switch circuitry that prevents the brake switch input to the EBCM/EBTCM from changing states while applying the brake. DTC C1295 is used in conjunction with DTC C1291 and DTC C1292 to determine the cause of an open brake switch malfunction.

Conditions for Setting the DTC

DTC C1295 can set after initialization is complete.

A malfunction exists if the brake switch input voltage is out of specification for one second. An open circuit exists when the brake switch input voltage is out of specification.

Action Taken When the DTC Sets

    • A malfunction DTC stores.
    • ABS/TCS disables.
    • The amber ABS/TCS warning indicators turns on.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTC function is used.
    • 100 drive cycles pass with no DTC detected.

Diagnostic Aids

Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction. Refer to the Scan Tool manual or Scan Tool Diagnostics located in this section for the procedure. Use the Data List of the Scan Tool verify proper brake switch operation. The Data List should display the brake switch as the brake is applied within 25 mm (1.0 in) of brake pedal travel.

Thoroughly inspect any circuitry that may cause the intermittent complaint for the following conditions:

    • Rubbed-through wire insulation
    • A broken wire inside the insulation
    • Backed out terminals
    • Improper mating
    • Broken locks
    • Improperly formed or damaged terminals
    • Poor terminal-to-wiring connections
    • Physical damage to the wiring harness

Important: Zero the J 39200 test leads before making any resistance measurements.

DTC C1295 Brake Lamp Switch Circuit Open

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Turn the ignition switch to the RUN position, engine OFF.
  2. Install a Scan Tool
  3. Select Data List on the Scan Tool
  4. Select Brake Switch Position on the Scan Tool

Does the Scan Tool indicate that the brake switch circuit is open?

--

Go to Step 3

Go to Step 4

3

Apply light pressure to the brake pedal while monitoring the Brake Switch Position on the Scan Tool

Does the Scan Tool indicate that the brake switch is on within 25 mm (1.0 in) of the brake pedal travel?

--

Go to Step 10

Go to Step 4

4

  1. Apply firm pressure to the brake pedal.
  2. Observe the rear brake lamps.

Are the rear brake lamps on?

--

Go to Step 5

Go to Exterior Lighting System Check

5

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the 24-way EBCM/EBTCM connector C1.
  3. Turn the ignition switch to the RUN position, engine OFF.
  4. Apply firm pressure to the brake pedal.
  5. Use the J 39200 in order to measure the voltage between the 24-way EBCM/EBTCM connector C1 terminal B9 and ground.

Is the voltage equal to or greater than the specified voltage?

10.0V

Go to Step 6

Go to Step 7

6

Inspect the 24-way EBCM/EBTCM connector C1 for the following conditions:

    • Terminal damage
    • Poor terminal contact
    • Terminal corrosion

Are poor terminal contact, terminal corrosion or damaged terminals evident?

--

Go to Step 8

Go to Step 9

7

Repair the open in CKT 17 from S205 to the EBCM/EBTCM.

Is the repair complete?

--

Go to Diagnostic System Check

--

8

Replace all the terminals or the connectors that exhibit the following conditions:

    • Poor terminal contact
    • Terminal corrosion
    • Damaged terminal(s).

Is the repair complete?

--

Go to Diagnostic System Check

--

9

Replace the EBCM/EBTCM. Refer to Electronic Brake and Traction Control Module Replacement .

Is the repair complete?

--

Go to Diagnostic System Check

--

10

The malfunction is intermittent or is not present at this time.

Is a concern still present?

--

Go to Diagnostic Aids

Go to Diagnostic System Check