Circuit Description
The brake switch indicates brake pedal status to the powertrain control module (PCM). When the brake pedal is operated, the switch sends a signal to the PCM, the PCM then cancels the operation of the torque converter clutch (TCC) lock-up while braking is in progress. This prevents the engine from stalling.
Conditions for Running the DTC
| • | The switch does not turn off even once the vehicle is driven (2-trip detection logic). |
| • | The ignition is ON. |
Conditions for Setting the DTC
The PCM detects a closed brake switch circuit, 12 volts, without changing for 2 seconds and the following events occur 8 times:
The vehicle must stop and go from 3 km/h (2 mph) to 30 km/h (19 mph) 10 times for 2 driving cycles before detecting a malfunction.
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL). |
| • | The PCM stores DTC P0724 in PCM history. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
Inspect the brake switch for proper mounting and operation.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Automatic Transmission Controls Schematics | ||||
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Important: Before clearing the DTC, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the powertrain control module (PCM). Caution: Refer to SIR Caution in the Preface section. Did the Brake Switch status change from Closed to Open? | -- | Go to Step 3 | Go to Step 4 | |
3 | Replace the brake switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | -- | Go to Step 6 | -- |
4 | Test the signal circuit of the brake switch for a short to power. Did you find and correct the condition? | -- | Go to Step 6 | Go to Step 5 |
5 | Replace the PCM. Refer to Powertrain Control Module Programming and Setup in Programming and Setup. Did you complete the replacement? | -- | Go to Step 6 | -- |
6 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | 0 volts | System OK | Go to Step 1 |
