For 1990-2009 cars

## DTC P0724 L61

### Circuit Description

The stop lamp switch is used to turn ON the stop lamps and serve as a brake pedal input to the PCM. The stop lamp switch contact is closed with the brake pedal depressed and the switch adjusted properly. Ignition voltage is supplied to the PCM through the stop lamp switch whenever the ignition is turned ON and the brake pedal is depressed. When the brake pedal is released, the PCM brake switch input goes low. The PCM monitors the brake switch input for low and high voltage faults under certain conditions. DTC P0724 sets when the vehicle has decelerated a set number of times and the voltage at the PCM remains low, indicating the brake pedal is always being released.

### Conditions for Setting the DTC

DTC P0724 will set if no voltage is present at the PCM brake switch input when:

• | The vehicle has accelerated 8 times in the following manner:

- | The vehicle speed is more than 32 km/h (20 mph) for 6 seconds.

- | The vehicle speed is between 8-32 km/h (5-20 mph) for 3 seconds.

- | The vehicle speed is less than 8 km/h (5 mph).

• | DTC P0502 and P0503 have not set for MY 2003.

DTC P0724 diagnostic runs continuously. If the brake switch state changes, the deceleration counter is reset.

DTC P0724 is a type C DTC.

### Diagnostic Aids

To locate an intermittent problem, use the scan tool to monitor the BRAKE SWITCH with the brake pedal depressed while wiggling the wires. The scan tool will read RELEASED when no voltage is present at the PCM brake input. Wiggling the wires while watching for a change from APPLIED to RELEASED may locate the area where an open or short to ground in the wiring could lie.

The stop lamp switch should have under 2 ohms resistance across its terminals when the plunger is all the way out.

The stop lamp switch plunger can be adjusted. Refer to Stop Lamp Switch Adjustment.

## DTC P0724 L81

### Circuit Description

The stop lamp switch indicates the brake pedal status to the transmission control module (TCM). The normally open stop lamp switch interrupts voltage to the TCM. Applying the brake pedal closes the switch and supplies voltage on circuit 20 to the TCM. When the TCM senses voltage at the stop lamp switch input, the TCM de-energizes the torque converter clutch solenoid valve. When the TCM detects an open stop lamp switch during accelerations, DTC P0724 sets.

### Conditions for Setting the DTC

DTC P0724 will set if the ignition voltage is present at the TCM brake switch input for 15 minutes continuously when the vehicle has accelerated 8 times in the following manner:

• | The vehicle speed is less than 8 km/h (5 mph).

• | The vehicle speed is between 8-32 km/h (5-20 mph) for 7 seconds.

• | The vehicle speed is greater than 32 km/h (20 mph) for 4 seconds.

DTC P0724 diagnostic runs continuously. If the brake switch state changes, the acceleration counter is reset.

DTC P0724 is a type C DTC.

### Diagnostic Aids

• | Ask about the customer's driving habits. Ask about the unusual traffic conditions and the stop-and-go driving.

• | Inspect the stop lamp switch for proper adjustment.