P0719
Brake Switch B Circuit Low.
- Generic
- Powertrain
- Generic code
- Medium severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- 19
- FaultThe specific fault in that area
What it means
P0719 is the generic code for a low signal on the Brake Switch B circuit, which is the second (redundant) brake pedal switch input used by the powertrain or transmission control unit. The control unit sees a voltage lower than expected, or a signal that disagrees with Brake Switch A, so it sets the fault. The exact switch layout and how the two signals are compared vary by model and engine.
Symptoms
- Brake lights not working, or staying on permanently
- Cruise control not working or cancelling unexpectedly
- Gear selector or shift lock will not release from park
- Harsh, delayed or restricted gear changes
- Engine hard to start on models that need the brake pressed to start
- Warning light on the dashboard
Possible causes
- Faulty or misadjusted brake pedal switch (B contact)likely
- Damaged wiring, short to earth or open circuit in the Brake Switch B circuitlikely
- Corroded or loose connector at the brake switch or control unitpossible
- Blown brake light or related circuit fusepossible
- Brake pedal bracket, plunger or stopper worn or out of positionpossible
- Faulty powertrain, transmission or body control unitrare
How to diagnose
- Read the stored codes and freeze frame data, and note whether other brake switch or brake light codes (such as P0571 or P0703) are present
- Check that the brake lights work and switch off when the pedal is released
- Inspect the brake switch, its plunger and pedal stopper for damage, wear or incorrect adjustment
- Check the relevant fuses and inspect the connector for corrosion, bent pins or water ingress
- View live data and confirm that both brake switch signals change state when the pedal is pressed and released
- Check the switch with a multimeter against the manufacturer's specification for resistance or continuity in each pedal position
- Test the Brake Switch B wire for open circuit, short to earth and short to supply, following the wiring diagram for the model
- Only after wiring and switch are proven good, consider the control unit and check for any applicable software updates
How to fix
- Replace the brake pedal switch and set it up to the manufacturer's procedure
- Repair or replace damaged wiring and terminals in the Brake Switch B circuit
- Clean or replace corroded connectors and secure them properly
- Replace blown fuses after finding the cause of the failure
- Repair or replace a worn pedal stopper or bracket so the switch operates correctly
- Repair or replace the control unit, or apply a software update, only if a fault is confirmed
Can I keep driving?
Medium severity
The car can usually be driven short distances, but faulty brake lights are unsafe and illegal, and shifting may be restricted. Have it repaired soon, and do not drive it if the brake lights are not working.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.