C1000 Brake Pedal Switch 1 Circuit - Performance

C1000 code - The ABS module detects an invalid signal between the master cylinder pressure applied and the Brake lamp switch output circuit for two minutes. If the Brake lamp switch output circuit is still active with no pressure applied, code C1000 is set. When the set conditions have been met and the brake switch input has been active for more than two consecutive minutes.

Possible Causes C1000 Code

• Brake signal 1 circuit shorted to voltage.
• Brake lamp switch operation.
• Antilock Brake System (ABS) Module.
• Totally Integrated Power Module (TIPM) or Body Control Module (BCM).

Step by step diagnose DTC C1000 Brake Pedal Switch 1 Circuit - Performance

Step 1. Verify the DTC is active

Note: Diagnose and repair all PCM and communication faults that are present before continuing with this test.

Note: If applicable make sure the stop lamp switch is properly adjusted in accordance with service information before proceeding.

Ignition on, engine not running. With the scan tool, read and erase DTC. Cycle the ignition from off to on. Press the brake pedal, with the scan tool, read DTC.

Is the DTC active at this time?

YES, go to step 2.

NO, perform the ABS Intermittent condition.

Step 2. Brake signal 1 circuit shorted to voltage

Example wiring

Ignition on engine not running, using a 12-volt test light connected to ground, back probe the brake signal 1 circuit.

Does the test light illuminate brightly?

YES, go to step 3.

NO, perform the ABS Intermittent condition.

Step 3. Stop lamp brake pedal switch shorted

Turn the ignition off to the lock position. Disconnect the stop lamp switch harness connector. Measure the resistance of the stop lamp switch between brake signal 1 circuit and fused B(+) circuit at the stop lamp switch harness connector.

Is there continuity?

YES, replace the stop lamp switch. Go to step 4.

NO, go to step 5.

Step 4. Check brake signal 1 circuit shorted to voltage

Connect the stop lamp switch harness connector. Ignition on, engine not running. Using a 12-volt test light connected to ground, back probe the brake pedal signal 1 circuit at the stop lamp switch harness connector.

Does the test light illuminate?

YES, go to step 5.

NO, repair the short to voltage in the brake signal 1 circuit.

Step 5. Check ABS module backfeeding voltage to brake signal 1 circuit

Turn ignition off to the lock position. Disconnect the ABS Module harness connector. Ignition on, engine not running, using a 12-volt test light connected to ground, test the brake signal 1 circuit at the stop lamp switch harness connector

Does the test light illuminate?

YES, go to step 6.

NO, replace the Antilock Brake System (ABS) Module. Perform the ABS Verification Test.

Step 6. Check TIPM/BCM module backfeeding voltage to brake signal 1 circuit

Turn the ignition off, disconnect the TIPM/BCM harness connector. Ignition on engine not running, using a 12-volt test light connected to ground, test the brake signal 1 circuit.

Does the test light illuminate?

YES, repair the short to voltage in the brake signal 1 circuit.

NO, replace and program the Tottally Integrated Power Module (TIPM) or Body Control Module (BCM).

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