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.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Throttle actuator a
- Throttle position sensor
- Ecm
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Deposits on throttle plate or bore
- TPS reference drifted
Possible symptoms
- Check engine light on
- Reduced throttle response, possible limp mode
- Hesitation or surging
- Idle too high or too low
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- Reduced-power or limp mode may occur
Related codes
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.