Torque Converter/Brake Switch B Circuit Low
The P0719 code indicates that the Powertrain Control Module (PCM) has detected a low voltage signal from the brake switch B circuit, which is used to control the torque converter clutch (TCC) operation. This circuit typically involves the brake pedal position sensor or switch that signals when the brake is applied. A low voltage condition may be caused by a faulty brake switch, wiring issues, or a problem with the PCM. This can prevent the TCC from engaging or disengaging properly, affecting transmission performance.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Torque converter clutch not engaging or disengaging
- Transmission slipping or harsh shifting
- Cruise control inoperative
2. Most Common Causes
- Faulty brake pedal switch (B circuit) with internal short to ground
- Brake switch B signal circuit wiring shorted to ground
- Damaged, corroded, or pushed-out terminals in brake switch connector
- Internal PCM/TCM failure in the input circuit (rare)
- Incorrect brake switch adjustment causing it to stay permanently activated
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check for related codes.
Step 2: Inspect the brake switch B circuit wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test the brake switch B operation using a multimeter; replace if faulty.
Step 4: Clear the code and test drive to see if it returns.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can cause transmission shifting issues and potential damage to the torque converter.
How much does it cost to fix?▼
The typical repair cost ranges from $50 to $150 for parts and labor, depending on the cause and vehicle model.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.