What it means
The control module detects a Brake Pedal Position Sensor A signal outside the expected range or performance criteria.
At a glance
- Usually lights the check-engine light
How it works
Brake Pedal Position Sensor A reports pedal movement to the control module for functions such as cruise cancellation and related brake controls. P057B sets when the signal is outside the expected range or does not track pedal movement correctly, which can result from sensor wear, misalignment, or a binding pedal mechanism.
Common causes
Most likely first.
- Brake pedal position sensor A worn or damaged
- Sensor misadjusted or poorly mounted
- Wiring or connector fault
- Brake pedal mechanism binding
Symptoms
- Check-engine light may come on
- Cruise control may not engage or may disengage unexpectedly
- Brake lights may behave erratically
- Brake pedal position display or related system response may be inconsistent
How to diagnose it
- Record freeze-frame data and graph Brake Pedal Position Sensor A while pressing and releasing the pedal slowly to check for a smooth, plausible change.
- Check brake-light operation and inspect whether the sensor is securely mounted and aligned with the pedal mechanism.
- Move the pedal by hand with the vehicle safely parked to check for binding, obstruction, or failure to return fully.
- Inspect sensor A wiring and connectors for damage or poor contact that could distort the position reading.
- Test sensor travel and mounting against the manufacturer's specification and compare its output with the module reading.
Common fixes
- Correct sensor A mounting or adjustment if it is loose or mispositioned.
- Remove an obstruction or repair a binding pedal mechanism.
- Repair damaged wiring or a poor sensor connector contact.
- Replace Brake Pedal Position Sensor A if its signal remains out of range during testing.
Can I keep driving?
Cruise control may disengage unexpectedly, and brake-light behavior may be inconsistent. Check the brake lights before driving, avoid cruise control, and stop using the vehicle if the pedal does not move or return normally.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.