Circuit Description
The Torque Converter Clutch (TCC) brake switch is used to indicate the status of the brake pedal (applied or released).
When the PCM detects a status change on the bake lamp circuit and the extended travel brake switch input without a transition on the TCC brake switch input, then DTC P0724 sets. DTC P0724 is a Type C DTC.
Conditions for Setting the DTC
| • | No VSS DTCs P0502 or P0503 are set. |
| • | No extended travel brake switch or stop lamp switch DTCs P1574 or P1575 are set. |
| • | No loss of PCM serial data DTC P1602 is set. |
| • | The TCC brake switch input indicates ignition volts. |
| • | Traction control or ABS is not active. |
| • | The difference in vehicle speed and a non-driven wheel speed is less than 10 km/h (6 mph). |
| • | The following conditions must occur 7 times without a status change on the TCC brake input: |
| 1. | Vehicle speed is greater than 32 km/h (20 mph) for more than 6 seconds. |
| 2. | Then the vehicle speed decreases to 8 km/h (5 mph) within 2.5 seconds and, during this time, the vehicle speed must drop by 10 km/h (6 mph) within 0.6 seconds during a deceleration. |
Action Taken When the DTC Sets
| • | SERVICE ELECTRICAL SYSTEM displays on the Driver Information Center (DIC). |
| • | The PCM uses the extended travel brake switch input or the stop lamp switch input for TCC control. |
| • | The PCM disables garage shift adapts. |
Conditions for Clearing the DIC/DTC
| • | The TCC brake switch input must indicate 0 volts for a minimum of 2 seconds. |
| • | 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
| • | Inspect the TCC brake switch for proper adjustment. |
| • | Check the customer's driving habits. |
| • | Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the brake switch connector. Look for the following conditions: |
| - | A bent terminal |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| • | When diagnosing for an intermittent open condition, massage the wiring harness while watching the test equipment for a change. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This Step ensures that you perform the Powertrain On-Board Diagnostic System Check.
-
This Step isolates the brake switch as the source for setting the DTC.
-
This Step inspects circuit 420 for a short to power, if the scan tool status never changes from released to applied.
-
This Step replaces the PCM after you have inspected the brake switch and all related circuitry.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | ||||||||
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Did the display change from Released to Applied? | -- | |||||||||
3 | Replace the TCC Brake Switch. Refer to Brake Switch Replacement, Section 5. Is the replacement complete? | -- | -- | |||||||
Inspect circuit 420 for a short to power. Refer to Electrical Diagnosis, Section 8. Did you find and correct the condition? | -- | |||||||||
Replace the PCM. Refer to PCM Replacement/Programming Section 6. Is the replacement complete? | -- | -- | ||||||||
6 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
