Circuit Description
The torque converter clutch (TCC) brake switch is used to indicate the status of the brake pedal, applied or released, to the powertrain control module (PCM). The normally-closed TCC brake switch supplies an ignition voltage input to the PCM. Applying the brake pedal opens the switch, interrupting voltage to the PCM. Releasing the brake pedal resumes voltage to the PCM. When the PCM senses 0 volts at the TCC brake switch signal circuit, the PCM de-energizes the TCC solenoid valve.
If the PCM detects an open TCC brake switch, stuck ON, 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 P0502 or P0503. |
| • | DTC P0719 has not passed this ignition cycle. |
Conditions for Setting the DTC
The TCC brake switch input is at 0 volts for 15 minutes and the following conditions occur eight times without a status change on the TCC brake input:
| • | The vehicle speed is less than 8 km/h (5 mph). |
| • | The vehicle accelerates to 32 km/h (20 mph) within 2-6 seconds. |
| • | Then 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 input for TCC scheduling. The PCM then uses throttle position and vehicle speed inputs to determine TCC application and release. Use of these inputs may result in a noticeable harsh apply or abrupt 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 DIC/DTC
| • | The PCM clears the DIC message when the condition no longer exists. |
| • | The TCC brake switch input indicates ignition voltage for 2 seconds. |
| • | 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 the DTC passes. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Disconnecting the brake switch connector, jumping the circuit, and observing a status change, isolates the brake switch as the source of the DTC.
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If the ignition 1 voltage circuit shorts to ground, the IGN 1 fuse opens.
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If the brake switch is properly adjusted, then the brake switch must be replaced.
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Replace the PCM only after you have completed the preceding diagnostic steps.
Step | Action | Values | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||
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. Did the TCC brake switch status change from Open to Closed? | -- | Go to Step 5 | Go to Step 3 | |||||||
Refer to Circuit Protection - Fuses in Wiring Systems. Is the fuse open? | -- | 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. Test the ignition 1 voltage circuit and the TCC Brake Switch Signal circuit of the TCC brake switch for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | -- | ||||||
Refer to Stop Lamp Switch Adjustment in Lighting Systems. Did the TCC brake switch require adjustment? | -- | Go to Step 9 | Go to Step 7 | |||||||
6 |
Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 9 | Go to Step 8 | ||||||
7 | Replace the TCC brake switch. Refer to Stop Lamp Switch Replacement in Lighting Systems. Did you complete the replacement? | -- | Go to Step 9 | -- | ||||||
Replace the PCM. Refer to Control Module References in Computer/Integrating Systems. Did you complete the replacement? | -- | Go to Step 9 | -- | |||||||
9 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 10 | Go to Step 2 | ||||||
10 | With the scan tool, observe the stored information, capture info. and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
