P057E: Brake Pedal Position Sensor A Circuit Intermittent/Erratic

What does P057E mean?

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. P057E means implausibly fast signal jumps within the valid range: GM sets it at jumps above 11 in 5 of 20 samples. Brief interruptions can also make GM's engine module learn a wrong rest position – it then sees the brake pressed and cuts power; GM names fretting at the 5 V reference or signal.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on (GM)
• Sporadic power reduction when accelerating
• Cruise control cutting out sporadically

Common causes

• High Loose contact or fretting corrosion at sensor or inline connector
• Medium Broken or chafed wire near the pedal
• Medium Sensor worn internally (signal jumping)
• Low Interference on the 5 V reference

Likelihood is a general estimate across vehicles; your make and model may differ.