GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 LeSabre 🢒 Transmission/Transaxle 🢒 Automatic Transaxle - 4T65-E 🢒 DTC P0719 Brake Switch Circuit Low Input

Object Number: 423308 Size: SF
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The TCC brake switch indicates brake pedal status to the PCM. The TCC brake switch indicates that the brake pedal is either applied or released. The normally-closed switch supplies battery voltage to the PCM. Applying the brake pedal opens the TCC brake switch, interrupting voltage to the PCM. When the PCM receives 0 volts at the TCC brake switch input, the PCM turns OFF the torque converter clutch pulse width modulation (TCC PWM) solenoid valve.

If the PCM detects an open brake switch (indicating pedal applied) during acceleration, then DTC P0719 sets. DTC P0719 is a type C DTC.

Conditions for Running the DTC

No VSS DTCs P0502 or P0503.

Conditions for Setting the DTC

The TCC brake switch indicates continuously open (0 volts) for more than 15 minutes and the following conditions occur 7 times consecutively:

    • The vehicle speed is less than 8 km/h (5 mph);
    • Then the vehicle speed is between 8 km/h (5 mph) and 32 km/h (20 mph) for at least 4 seconds;
    • Finally, the vehicle speed remains above 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 TCC brake switch for TCC scheduling when all of the following conditions are met:
       - The TP angle is greater than 6%.
       - The vehicle speed is greater than 60 km/h (37 mph).
       - The TP angle was previously greater than 12% while the vehicle speed was greater than 68 km/h (42 mph).
       - The TCC brake switch has not indicated OFF for more than 2 seconds this trip.
    • 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 consecutive 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 connectors at the controller, the component and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step isolates the fault between the TCC brake switch and the harness.

DTC P0719 Brake Switch Circuit Low

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls

2
  1. Install the Scan Tool .
  2. Turn the ignition switch to the RUN position.

    3. Important: Before clearing the DTCs, use the Scan Tool in order to record the Failure Records for reference. Using the Clear Info function will erase the stored Failure Records from the PCM.

  3. Record the Failure Records.
  4. Clear the DTCs.

Did you record the Failure Records?

--

Go to Step 3

--

3

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution.

  1. Remove the fuse in the power feed circuit of the TCC brake switch.
  2. Inspect the TCC brake switch fuse for an open.
  3. Replace the fuse if necessary.

    4. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was a condition found?

--

Go to Step 4

Go to Step 6

4

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution.

  1. Disconnect the TCC brake switch connector.
  2. Inspect circuit 420 (PPL) for a short to ground.

    3. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was a condition found?

--

Go to Step 8

Go to Step 5

5

Important: The condition that affects this circuit may exist in other connecting branches of the circuit. Refer to Power Distribution Schematics in Wiring Systems for complete circuit distribution.

Inspect circuit 1039 (PNK) of the engine wiring harness for a short to ground.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was a condition found?

--

Go to Step 8

--

6

  1. Monitor brake switch on the Scan Tool .
  2. Disconnect the TCC brake switch connector.
  3. Connect a fused jumper wire from terminal A to terminal B of the TCC brake switch connector.

Does the TCC brake switch status change from Open to Closed?

--

Go to Step 9

Go to Step 7

7
  1. Inspect circuit 420 (PPL) for an open.
  2. Inspect circuit 1039 (PNK) for an open.

    3. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Was a condition found?

--

Go to Step 8

Go to Step 10

8
  1. Repair the circuit(s) as necessary.

    2. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

  2. Reinstall or replace the fuse as necessary.

Is the repair complete?

--

Go to Step 11

--

9

Replace the TCC brake switch.

Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the repair complete?

--

Go to Step 11

--

10

Replace the PCM.

Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the repair complete?

--

Go to Step 11

--

11

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
    4. • Turn the ignition switch to the RUN position.
    • Apply and release the brake pedal.
    • The TCC brake switch must be Closed (pedal released) for more than 2 seconds.
  4. Select Specific DTC.
  5. Enter DTC P0719.

Has the test run and passed?

--

System OK

Go to Step 1