Circuit Description
The brake switch reports brake pedal status to the Powertrain Control Module (PCM). The brake switch indicates that the brake pedal is either applied or released. This normally-closed switch supplies battery voltage on circuit 420 to the PCM. Applying the brake pedal opens the brake switch, interrupting voltage to the PCM. When the PCM receives 0 volts at the brake switch input, the PCM turns OFF the TCC Solenoid Valve.
When the PCM detects a closed brake switch (pedal released) during a number of decelerations, then DTC P0724 sets. DTC P0724 is a type D DTC.
Conditions for Setting the DTC
| • | No VSS DTCs P0502 or P0503. |
| • | The vehicle speed is greater than 32 km/h (20 mph) for more than 6 seconds. |
| • | The vehicle speed decreases to 8 km/h (5 mph) and takes more than 4 seconds. |
| • | The vehicle speed is less than 8 km/h (5 mph). |
| • | The above conditions must occur more than 7 times with the brake switch continuously Closed (voltage to PCM), without opening for 2 seconds. |
Action Taken When the DTC Sets
The PCM does not illuminate the Malfunction Indicator Lamp (MIL).
Conditions for Clearing the DTC
A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.
Diagnostic Aids
| • | Ensure that the brake switch is properly adjusted. |
| • | Inspect the wiring at the PCM, the brake switch connector and all other circuit connecting points 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 |
| - | Moisture intrusion |
| - | Corrosion |
| • | When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change. |
Test Description
The number below refers to the step numbers on the diagnostic table.
-
A Scan Tool display that changes from Closed to Open, when the brake switch is disconnected, indicates a faulty brake switch.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls | |||||
Important: Before clearing the DTCs, use the Scan Tool in order to record the Failure Records for reference. The Clear Info function will erase the stored Failure Records from the PCM. Did the brake switch status change from Closed to Open? | -- | |||||||
3 | Replace the brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Is the replacement complete? | -- | -- | |||||
4 | Inspect circuit 420 for a short to power. Repair circuit 420 if necessary. Refer to General Electrical Diagnosis in Wiring Systems. Was a condition found and corrected? | -- | ||||||
5 | Inspect circuits 420 and 39 for a short together. Repair circuits 420 or 39 if necessary. Refer to General Electrical Diagnosis in Wiring Systems. Was a condition found and corrected? | -- | ||||||
6 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||
7 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
