4L80-E / 4L85-E Automatic Transmission

DTC P0724





Circuit Description with 4L80-E / 4L85-E Automatic Transmission
The normally open TCC Brake switch indicates brake pedal status to the Powertrain Control Module (PCM). Applying the brake pedal closes the switch, supplying voltage to the PCM. Releasing the brake pedal interrupts voltage to the PCM.
If the PCM detects a closed TCC/Stoplamp switch, Stuck ON, during accelerations, then DTC P0724 sets. DTC P0724 is a type C DTC.

Conditions for Running the DTC
^ No AT VSS sensor DTCs P0722 or P0723
^ The PCM detects a closed TCC Brake switch or circuit, and the following sequence of events occur:
1. The vehicle speed is less than 8 km/h (5 mph).
2. The vehicle speed is 8 - 32 km/h (5 - 20 mph) for 3.1 seconds.
3. The vehicle speed is greater than 32 km/h (20 mph) for 7 seconds.
^ DTC P0724 has not passed.

Conditions for Setting the DTC
^ The TCC Brake switch is closed for 900 seconds (15 minutes).
^ All conditions are met for eight occurrences.

Action Taken When the DTC Sets
^ The PCM does not illuminate the Malfunction Indicator Lamp (MIL).
^ For TCC scheduling, the PCM disregards the TCC Brake switch state if the APP sensor is greater than 0.5 percent and the vehicle speed is greater than 40 km/h (25 mph).
^ 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
^ Ask about the customer driving habits and any unusual driving conditions he or she might have, such as stop and go traffic or expressway driving.
^ Inspect the brake switch for proper mounting and operation.

Test Description
The number below refers to the step number on the diagnostic table.
2. This step isolates the TCC Brake switch as a source for setting the DTC.