DTC P0724 4.8L and 6.0L
Circuit Description
The torque converter clutch (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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0724 Brake Switch Circuit High Voltage
Conditions for Running the DTC
| • | No VSS DTCs P0502 or P0503. |
| • | The ignition switch is in the ON position. |
| • | The system voltage is 8-12 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. |
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 - Vehicle? | Go to Step 2 | |
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. Caution: Refer to SIR Caution in the Preface section. Did the TCC Brake switch status change from CLOSED to OPEN? | Go to Testing for Intermittent Conditions and Poor Connections | 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 . 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 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 . Did you find and correct the condition? | Go to Step 7 | Go to Step 6 |
6 | Replace the PCM. Refer to Control Module References for replacement, setup, and programming. 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? | System OK |
DTC P0724 6.6L
Circuit Description
The stop lamp switch indicates the brake pedal status to the transmission control module (TCM). The brake switch is a normally-closed switch that supplies battery voltage on the CHMSL supply voltage circuit to the TCM. Applying the brake opens the stop lamp switch, interrupting voltage to the TCM. When the brake is released, the TCM receives a constant voltage signal input. If the TCM receives a 0 voltage signal input at the CHMSL supply voltage circuit, and the torque converter clutch (TCC) is engaged, the TCM de-energizes the TCC solenoid valve. The TCM disregards the brake switch input for TCC scheduling if there is a brake switch circuit fault.
When the TCM detects an open brake switch circuit during accelerations, then DTC P0724 sets. DTC P0724 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0724 Brake Switch Circuit High Voltage
Conditions for Running the DTC
| • | No OSS DTCs P0722 or P0723. |
| • | The vehicle speed is less than 8 km/h (5 mph), then the vehicle speed is between 8 km/h (5 mph) and 40 km/h (25 mph) for 6 seconds or less, then the vehicle speed is greater than 40 km/h (25 mph) for greater than 5 seconds. |
Conditions for Setting the DTC
The TCM detects the brake switch circuit is open 8 times during acceleration cycles and the brake switch voltage is high for 900 seconds (15 minutes) or greater.
Action Taken When the DTC Sets
| • | The TCM does not request the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL). |
| • | The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM records this information as a Failure Record. |
| • | The TCM stores DTC P0724 in TCM history. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC. |
| • | The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without a non-emission related diagnostic fault occurring. |
Diagnostic Aids
| • | Inspect the brake switch for proper mounting and operation. |
| • | Inspect for ABS DTCs. A faulty ABS condition may contribute to setting DTC P0724. |
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 - Vehicle? | Go to Step 2 | |
Important: Before clearing the DTC, use the scan tool in order to record the ECM and TCM Failure Records. Using the Clear Info function erases the Failure Records from the ECM. Caution: Refer to SIR Caution in the Preface section. Did the TCC Brake Switch status on the scan tool change from Closed to Open? | Go to Step 3 | Go to Step 4 | |
3 | Replace the brake switch. Refer to Stop Lamp Switch Replacement . Did you complete the replacement? | Go to Step 6 | -- |
4 |
Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics for complete circuit distribution. Test the stop lamp supply voltage signal circuit of the brake switch for a short to voltage between the stop lamp switch and fuse block-body or fuse block-body and TCM. Refer to Testing for a Short to Voltage and Wiring Repairs . Did you find and correct the condition? | Go to Step 6 | Go to Step 5 |
5 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. 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? | Go to Step 7 | Go to Step 2 |
7 | 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? | System OK |
