4L80-E / 4L85-E Automatic Transmission

DTC P0724





Circuit Description with 4L80-E / 4L85-E Automatic Transmission
The torque converter clutch (TCC)/stop lamp 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 brake pedal is applied.

If the PCM detects a closed TCC/Stop lamp 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 AT VSS DTC P0502 or P0503.

Conditions for Setting the DTC
^ All conditions are met for 10 occurrences.
^ The PCM detects a closed TCC/Stop lamp switch circuit, 12 volts, during decelerations.
^ The following sequence of events occurs 10 consecutive times:
1. The vehicle speed is greater than 40 km/h (25 mph) for 7 seconds.
2. Then the vehicle speed is 8-40 km/h (5-25 mph) for 2.5 seconds.
3. 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 numbers on the diagnostic table.
3. This step isolates the TCC/stop lamp switch as a source for setting the DTC.