P0719

DTC P0719





Circuit Description with 4L60-E / 4L65-E Automatic Transmission
The brake switch indicates brake pedal status to the Powertrain Control Module (PCM). The brake switch is a normally-closed switch that supplies battery voltage on the Torque Converter Clutch (TCC) brake switch signal circuit to the PCM. Applying the brake pedal opens the switch, interrupting voltage to the PCM. When the brake pedal is released, the PCM receives a constant voltage signal. If the PCM receives a zero voltage signal at the brake switch input, and the TCC is engaged, the PCM de-energizes the TCC solenoid valve. The PCM disregards the brake switch input for TCC scheduling if there is a brake switch circuit fault.

When the PCM detects an open brake switch circuit, 0 volts, low input, 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 Vehicle Speed Sensor (VSS) DTC's P0502 or P0503.
^ The ignition is ON.
^ DTC P0719 has not passed.

Conditions for Setting the DTC
The PCM detects an open brake switch or circuit, 0 volts, for 15 minutes without changing for 2 seconds, and the following events occur 8 times:
1. The vehicle speed is less than 8 km/h (5 mph);
2. Then the vehicle speed is 8 - 32 km/h (5 - 20 mph) for 4 seconds;
3. Then the vehicle speed is greater than 32 km/h (20 mph) for 6 seconds.

Action Taken When the DTC Sets
^ The PCM does not illuminate the Malfunction Indicator Lamp (MIL).
^ The PCM disregards the brake switch input for TCC scheduling.
^ The PCM uses throttle position and vehicle speed to determine application and release of the TCC.
^ 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 can clear the DTC.
^ 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/or 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.
^ Inspect for Antilock Brake System (ABS) DTC's. A faulty ABS condition may contribute to setting DTC P0719.

Test Description








The number below refers to the step number on the diagnostic table.
3. This step isolates the brake switch as a source for setting the DTC.