4L80-E / 4L85-E Automatic Transmission
DTC P0719 (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 an open TCC brake switch circuit during accelerations, then DTC P0719 sets. DTC P0719 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0719 Brake Switch Circuit Low Voltage
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 P0719 sets if the PCM detects an open brake switch or circuit, 0 volts, during vehicle acceleration and the following conditions occur eight times:
* The vehicle speed is less than 8 km/h (5 mph).
* Then, the vehicle speed is 8-40 km/h (5-25 mph) for 1.7 seconds.
* Then, the vehicle speed is greater than 40 km/h (25 mph) for 7 seconds.
Action Taken When the DTC Sets
* The PCM does not illuminate the malfunction indicator lamp (MIL).
* For TCC scheduling, the PCM disregards the brake switch state if the TP sensor is 1.5 percent or greater and the vehicle speed is 32 km/h (20 mph) or greater.
* 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 P0719 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 DTC passes.
Diagnostic Aids
Inspect the brake switch for proper mounting and operation.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
4. This step tests for TCC brake switch voltage to the PCM connector.
7. This step isolates the TCC brake switch as a source for setting the DTC.
10. This step tests for a short to ground in the voltage circuit to the TCC brake switch.
12. This step tests for a short to ground in the TCC brake switch circuit, from the TCC brake switch to the PCM.
13. This step isolates the PCM as a source for causing the fuse to open.
