P0724

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The brake switch indicates the brake pedal status. The normally closed brake switch supplies a B+ signal on circuit 420 to the VCM. The signal voltage circuit opens when the brakes are applied. The VCM uses the signal voltage circuit in order to de-energize the TCC Pulse Width Modulated (PWM) Sol. valve when the brakes are applied.

When the VCM detects a closed brake switch during decelerations, then DTC P0724 sets. DTC P0724 is a type D DTC.

Conditions for Setting the DTC

^ No Vehicle Speed Sensor (VSS) DTC P0502.
^ The VCM detects a closed brake switch/circuit (12 volts) for 2 seconds during decelerations.
^ The following sequence of events occurs seven consecutive times:

- The vehicle speed is greater than 32 km/h (20 mph) for 6 seconds.
- Then the vehicle speed is 8-32 km/h (5-20 mph) for 4 seconds.
- Then the vehicle speed is less than 8 km/h (5 mph).

Action Taken When the DTC Sets

^ The VCM does not illuminate the Malfunction Indicator Lamp (MIL).

Conditions for Clearing the DTC

^ A scan tool can clear the DTC from the VCM history. The VCM clears the DTC from the VCM history if the vehicle completes 40 warm-up cycles without a failure reported.
^ The VCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the VCM.

Diagnostic Aids

^ Inspect the wiring for poor electrical connections at the VCM. Inspect the wiring for poor electrical connections at the TCC brake switch. Look for the following conditions:

- A bent terminal
- A backed out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation

^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
^ Ask about the customer's driving habits and any unusual driving conditions he or she might have, such as stop and go traffic or expressway driving.
^ Inspect the brake switch for proper mounting and adjustment.
^ Inspect for the most current calibration I.D. and the latest bulletins.
^ First diagnose and clear any engine DTCs or TP Sensor codes that are present. Then inspect for any transmission DTCs that may have reset.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

2. This step isolates the brake switch as a source for setting the DTC.