The brake switch indicates brake pedal status to the transmission control module (TCM). The normally-closed brake switch supplies ignition voltage to the TCM. Applying the brake pedal opens the switch, interrupting voltage to the TCM. Releasing the brake pedal resumes voltage to the TCM.

P0719

P0724

P0719

DTC P0719 sets if the TCM detects an open brake switch or circuit and the following conditions occur eight times:

P0724

DTC P0724 sets if the TCM detects a closed brake switch or circuit, 12 volts, for 15 minutes during vehicle acceleration and the following conditions occur eight times:

DTCs P0719 and P0724 are Type C DTCs.

DTCs P0719 and P0724 are Type C DTCs.

Schematic Reference

Automatic Transmission Controls Schematics

Connector End View Reference

Electrical Information Reference

Scan Tool Reference

DTC Type Reference

Special Tools

J 35616 GM Terminal Test Kit

Start the engine. With the vehicle in Park and at normal operating temperature, observe the TCC Brake Switch parameter on the scan tool. The TCC Brake Switch parameter should display Closed with the brake pedal released. Apply the brake pedal and the TCC Brake Switch parameter should display Open.

1. Install a scan tool. Turn ON the ignition, leaving the engine OFF. Observe the TCC Brake Switch parameter. The parameter should display Closed.

⇒	If the scan tool displays Open, disconnect the stop lamp switch connector.

2. Observe the TCC Brake Switch parameter on the scan tool with the stop lamp switch connector disconnected. The parameter should display Open.

⇒	If the scan tool displays Closed after the stop lamp switch connector disconnected, test the stop lamp switch.

⇒	If the scan tool displays Open after the stop lamp switch connector is disconnected, test the stop lamp switch signal circuit for a short to voltage.

3. While observing the TCC brake switch parameter on the scan tool, use the J 35616 GM terminal test kit and install a fused jumper wire between the ignition 1 voltage circuit and the stop lamp switch signal circuit. The TCC brake switch parameter should change from Closed to Open when the fused jumper wire is installed.

⇒	If the TCC brake switch parameter changes, replace the stop lamp switch.

4. Inspect the STOP LPS fuse; refer to Circuit Protection - Fuses . The fuse should not be blown.

⇒	If the fuse is blown, test the ignition 1 voltage circuit and the stop lamp switch signal circuit for a short to ground.

5. Using a DMM, measure the voltage between the ignition 1 voltage circuit and ground at the stop lamp switch connector. The voltage should be near 12 volts.

⇒	If the voltage is not near the specified voltage, test the ignition 1 voltage circuit for an open or high resistance.

6. Using the J 35616 GM terminal test kit measure the resistance of the stop lamp switch signal circuit between the BCM and the stop lamp switch. The resistance should be less than 10 ohms.

⇒	If the resistance is greater than 10 ohms, test the stop lamp switch signal circuit for an open or high resistance.

⇒	If all circuits and connections test normal, replace the BCM.

Inspect the stop lamp switch for proper adjustment; refer to Stop Lamp Switch Adjustment . With the stop lamp switch removed, use a DMM to measure to resistance across the pins for the ignition 1 voltage circuit and the stop lamp switch signal circuit. With the plunger released on the stop lamp switch the resistance should display infinite on the DMM. With the plunger depressed on the stop lamp switch the resistance should display less than 10 ohms.

Perform the Diagnostic Repair Verification after completing the repair.