P057CBrake Pedal Position Sensor A Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- The brake pedal position sensor A is an analogue 5 V sensor giving pedal travel continuously; its rest position (about 1 V) is learned. GM reads it in the engine module from about 2012 and uses it as an enabling condition of transmission monitors – hence type A, warning lamp after one trip, unlike cruise control codes. On any circuit fault GM sets the pedal to 0 %, so brake detection relies on the brake light switch. P057C means the signal is too low – a short to ground: GM below 5 in 20 of 32 samples. GM bulletins for 2012–14 pick-ups and SUVs name connector X205 under the left defroster duct, with cruise, brake light and stability messages and reduced power.
- What you may notice
- Check engine light on (GM, one trip)
- Cruise control, brake light or stability functions restricted
- Reduced power when accelerating
- Likely causes
- LikelyConnector or terminals at sensor or inline connector (GM X205) loose, pushed back or corroded
- PossibleSignal or 5 V reference shorted to ground
- PossibleSensor faulty internally
- Rare5 V reference pulled down by another sensor
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €40 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.