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For 1990-2009 cars only

DTC P0719 Brake Switch Circuit Low Input 4.3L


Object Number: 366557  Size: MF
Automatic Transmission Components
Automatic Transmission Controls Schematics 4.3L
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The brake switch indicates brake pedal status to the vehicle control module (VCM). The brake switch is a normally-closed switch that supplies battery voltage on circuit 420 to the VCM. Applying the brake pedal opens the switch, interrupting voltage to the VCM. When the brake pedal is released, the VCM receives a constant voltage signal. If the VCM receives a zero voltage signal at the brake switch input, and the torque converter clutch (TCC) is engaged, the VCM de-energizes the TCC solenoid valve. The VCM disregards the brake switch input for TCC scheduling if there is a brake switch circuit fault (Refer to Diagnostic Aids).

When the VCM detects an open brake switch circuit (0 volts, low input) during accelerations, then DTC P0719 sets. DTC P0719 is a type D DTC.

Conditions for Running the DTC

    • No VSS assembly DTCs P0502 or P0503.
    • The ignition switch is in the RUN position.

Conditions for Setting the DTC

The VCM detects an open brake switch or circuit (0 volts) for 15 minutes without changing for 2 seconds, and the following events occur seven times:

    • The vehicle speed is less than 8 km/h (5 mph);
    • then the vehicle speed is 8-32 km/h (5-20 mph) for 4 seconds;
    • then the vehicle speed is greater than 32 km/h (20 mph) for 6 seconds.

Action Taken When the DTC Sets

    • The VCM does not illuminate the malfunction indicator lamp (MIL).
    • The VCM disregards the brake switch input for TCC scheduling.
    • The VCM stores DTC P0719 in VCM history.

Conditions for Clearing the DTC

    • A scan tool clears the DTC from VCM history.
    •  The VCM clears the DTC from VCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
    • The VCM 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 VCM.

Diagnostic Aids

    • Inspect the wiring at the VCM, the brake switch connector and all other circuit connecting points for the following conditions:
       - A backed out terminal
       - A damaged terminal
       - Reduced terminal tension
       - A chafed wire
       - A broken wire inside the insulation
       - Moisture intrusion
       - Corrosion
    • When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
    • If the VCM detects a brake switch fault, then the brake switch input is disregarded for TCC scheduling. The VCM then uses throttle position and vehicle speed to determine TCC application and release. Use of these inputs may result in a noticeable harsh apply or abrupt release of the TCC.
    • Ask about the customer's driving habits. Ask about unusual driving conditions (e.g. stop and go, expressway, etc.).
    • Inspect the brake switch for proper mounting and operation.

Test Description

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

  1. This step isolates the brake switch as a source for setting the DTC.

DTC P0719 Brake Switch Circuit Low (4.3L)

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. With the engine OFF, turn the ignition switch to the RUN position.
  3. Important: Before clearing the DTC, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the VCM.

  4. Record the DTC Failure Records.
  5. Clear the DTC.
  6. Select TCC Brake Switch on the scan tool.
  7. Disconnect the brake switch connector from the brake switch.
  8. Connect a test lamp from cavity D of the brake switch connector to ground.

Is the test lamp ON?

--

Go to Step 3

Go to Step 4

3

Install a fused jumper wire from terminal C to terminal D of the brake switch connector.

Did the TCC Brake Switch status change from Open to Closed?

--

Go to Step 7

Go to Step 9

4

  1. Remove the BRAKE fuse.
  2. Inspect the fuse for an open.
  3. Refer to General Electrical Diagnosis in Wiring Systems.

Is the fuse open?

--

Go to Step 5

Go to Step 8

5

  1. Inspect circuit 441 (BRN) for a short to ground condition.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find a short to ground condition?

--

Go to Step 11

Go to Step 6

6

    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. Inspect circuit 420 (PPL) for a short to ground condition.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find a short to ground condition?

--

Go to Step 11

Go to Step 10

7

Replace the brake switch.

Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the replacement complete?

--

Go to Step 11

--

8

  1. Inspect circuit 441 (BRN) for an open condition.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct an open condition?

--

Go to Step 11

--

9

    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. Inspect circuit 420 (PPL) for an open.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find an open condition?

--

Go to Step 11

Go to Step 10

10

Replace the VCM.

Refer to VCM Replacement/Programming in Engine Controls.

Is the replacement complete?

--

Go to Step 11

--

11

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. With the engine OFF, turn the ignition switch to the RUN position.
  4. Apply and release the brake pedal.
  5. Verify that the scan tool TCC Brake Switch status indicates Closed (12 volts) for 2 seconds.
  6. Select Specific DTC.
  7. Enter DTC P0719.

Has the test run and passed?

--

System OK

Go to Step 1

DTC P0719 Brake Switch Circuit Low Input 4.8L and 5.3L


Object Number: 366576  Size: MF
Automatic Transmission Components
Automatic Transmission Controls Schematics V8 Gas
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

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 circuit 420 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 torque converter clutch (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 (Refer to Diagnostic Aids).

When the PCM detects an open brake switch circuit (0 volts, low input) during accelerations, then DTC P0719 sets. DTC P0719 is a type D DTC.

Conditions for Running the DTC

    • No VSS assembly DTCs P0502 or P0503.
    • The ignition switch is in the RUN position.

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 seven times:

    • The vehicle speed is less than 8 km/h (5 mph);
    • then the vehicle speed is 8-32 km/h (5-20 mph) for 4 seconds;
    • 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 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 wiring at the PCM, the brake switch connector and all other circuit connecting points for the following conditions:
       - A backed out terminal
       - A damaged terminal
       - Reduced terminal tension
       - A chafed wire
       - A broken wire inside the insulation
       - Moisture intrusion
       - Corrosion
    • When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
    • If the PCM detects a brake switch fault, then the brake switch input is disregarded for TCC scheduling. The PCM then uses throttle position and vehicle speed to determine TCC application and release. Use of these inputs may result in a noticeable harsh apply or abrupt release of the TCC.
    • Ask about the customer's driving habits. Ask about unusual driving conditions (e.g. stop and go, expressway, etc.).
    • Inspect the brake switch for proper mounting and operation.

Test Description

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

  1. This step isolates the brake switch as a source for setting the DTC.

DTC P0719 Brake Switch Circuit Low (4.8L and 5.3L)

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. With the engine OFF, turn the ignition switch to the RUN position.
  3. Important: Before clearing the DTC, use the scan tool in order to record the Failure Records. Using the Clear Info function erases the Failure Records from the PCM.

  4. Record the DTC Failure Records.
  5. Clear the DTC.
  6. Select TCC Brake Switch on the scan tool.
  7. Disconnect the brake switch connector from the brake switch.
  8. Connect a test lamp from cavity D of the brake switch connector to ground.

Is the test lamp ON?

--

Go to Step 3

Go to Step 4

3

Install a fused jumper wire from terminal C to terminal D of the brake switch connector.

Did the TCC Brake Switch status change from Open to Closed?

--

Go to Step 7

Go to Step 9

4

  1. Remove the BRAKE fuse.
  2. Inspect the fuse for an open.
  3. Refer to General Electrical Diagnosis in Wiring Systems.

Is the fuse open?

--

Go to Step 5

Go to Step 8

5

  1. Inspect circuit 441 (BRN) for a short to ground condition.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find a short to ground condition?

--

Go to Step 11

Go to Step 6

6

    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. Inspect circuit 420 (PPL) for a short to ground condition.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find a short to ground condition?

--

Go to Step 11

Go to Step 10

7

Replace the brake switch.

Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the replacement complete?

--

Go to Step 11

--

8

  1. Inspect circuit 441 (BRN) for an open condition.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct an open condition?

--

Go to Step 11

--

9

    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. Inspect circuit 420 (PPL) for an open condition.
  2. Refer to General Electrical Diagnosis in Wiring Systems.

  3. Repair the circuit if necessary.
  4. Refer to Wiring Repairs in Wiring Systems.

Did you find an open condition?

--

Go to Step 11

Go to Step 10

10

Replace the PCM.

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

Is the replacement complete?

--

Go to Step 11

--

11

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. With the engine OFF, turn the ignition switch to the RUN position.
  4. Apply and release the brake pedal.
  5. Verify that the scan tool TCC Brake Switch status indicates Closed (12 volts) for 2 seconds.
  6. Select Specific DTC.
  7. Enter DTC P0719.

Has the test run and passed?

--

System OK

Go to Step 1