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 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 stop lamp 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:
| • | Vehicle has decelerated eight times in one ignition cycle in the following manner: |
| • | Vehicle speed is greater than 32 km/h (20 mph) for 6 seconds, then vehicle speed is between 8 and 32 km/h (5-20 mph) for 4 seconds, then vehicle speed is less than 8 km/h (5 mph). |
DTC P0724 diagnostic runs continuously once the above conditions have been met.
P0724 is a (type D) DTC
Diagnostic Aids
To locate an intermittent problem, use the scan tool to monitor CRUISE BRAKE/CLUTCH SW with brake pedal depressed while wiggling wires. The Scan tool will read RELEASED when no voltage is present at the PCM brake switch input. Wiggling 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 Adjustment" procedure in this section if adjustment is needed.
DTC P0724
