Torque Converter/Brake Switch B Circuit Low
The P0719 code indicates that the powertrain control module (PCM) has detected an abnormally low voltage signal from the brake switch 'B' circuit. This circuit is responsible for signaling the transmission to disengage the torque converter clutch (TCC) when the brake pedal is depressed.
While the vehicle can usually still be driven, a malfunctioning brake switch circuit can prevent the torque converter clutch from disengaging, potentially causing the engine to stall when coming to a stop.
Common symptoms
- Illuminated Check Engine Light
- Engine stalling when coming to a stop
- Torque converter clutch fails to engage or disengage
- Decreased fuel economy at highway speeds
- Brake lights may stay on or not function properly
Likely causes
- Faulty or misadjusted brake switch
- Damaged, corroded, or loose wiring in the brake switch circuit
- Blown fuse in the brake light or switch circuit
- Failed torque converter clutch solenoid
- Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM)
What to check before replacing parts
Verify brake light operation
Look for: Check if the brake lights turn on and off correctly when the pedal is pressed and released, which helps indicate basic switch function.
Inspect the brake switch adjustment
Look for: Ensure the switch is properly aligned with the brake pedal arm and fully depresses the plunger when the pedal is released.
Test the brake switch with a multimeter
Look for: Check for proper continuity and resistance changes across the switch terminals when the pedal is actuated to confirm internal switch integrity.
Inspect the wiring harness and connectors
Look for: Look for chafed wires, melted insulation, or corroded pins in the circuit between the brake switch and the PCM.
Measure voltage at the PCM/TCM connector
Look for: Verify that the correct voltage signal is reaching the control module when the brake pedal is pressed, which rules out wiring breaks.
This page explains the generic P0719 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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