Circuit Description
The TCC brake switch indicates the brake pedal status. The normally closed TCC brake switch supplies a B+ signal to the powertrain control module (PCM). The signal voltage circuit opens when the brakes are applied.
If the PCM detects a closed TCC brake switch during decelerations, then DTC P0724 sets. DTC P0724 is a type C DTC.
Conditions for Running the DTC
| • | No VSS DTCs. |
| • | The ignition switch is in the ON position. |
| • | The system voltage is 8-18 volts. |
Conditions for Setting the DTC
DTC P0724 sets if the PCM detects a closed brake switch or circuit, 12 volts, during vehicle deceleration and the following conditions occur ten times:
| • | The vehicle speed is greater than 40 km/h (25 mph) for 7 seconds. |
| • | Then, the vehicle speed is 8-40 km/h (5-25 mph) for 2.5 seconds. |
| • | Then, the vehicle speed is less than 8 km/h (5 mph). |
Action Taken When the DTC Sets
| • | The PCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records. |
| • | The PCM stores DTC P0724 in PCM history. |
Conditions for Clearing the DTC
| • | A scan tool clears the DTC from PCM history. |
| • | 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 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 number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 6.0L |
2 |
Important: Before clearing the DTCs, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the PCM. Select TCC Brake switch on the scan tool. Did the TCC Brake switch status change from CLOSED to OPEN? | Go to Intermittent Conditions in Engine Controls - 6.0L | Go to Step 3 |
Did the TCC Brake switch status change from CLOSED to OPEN? | Go to Step 4 | Go to Step 5 | |
4 | Replace the stop lamp switch. Refer to Stop Lamp Switch Replacement in Lighting Systems. Did you complete the replacement? | Go to Step 7 | -- |
5 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution. Test the TCC brake switch signal circuit for a short to voltage. Refer to Testing for a Short to Voltage and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 7 | Go to Step 6 |
6 | Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement in Engine Controls - 6.0L. Did you complete the replacement? | Go to Step 7 | -- |
7 | Perform the following procedure in order to verify the repair:
Does the scan tool TCC Brake switch status change from CLOSED to OPEN? | Go to Step 8 | Go to Step 2 |
8 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 6.0L | System OK |
