OBD-II code · Powertrain (generic, extended)

P2C99 Throttle Actuator A Control Exceeded Learning Limit

The required adaptation offset for throttle actuator A exceeds the calibrated learning window. Mechanical wear, deposit build-up, or sensor drift beyond compensation.

Is it safe to drive with P2C99?

The car may go into limp mode (reduced power). Get it diagnosed before a long trip.

Common causes

  • Most likelyDeposits on throttle plate or bore
  • PossibleTPS reference drifted

Symptoms

  • Check engine light on
  • Reduced throttle response, possible limp mode
  • Hesitation or surging
  • Idle too high or too low

Repair at a glance

Difficulty
Easy
DIY friendly
Often, with basic tools
Typical labour
0.5–2 h
Emissions test
Likely to fail
Parts involved
Throttle Actuator A, Throttle Position Sensor, Ecm

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.