Throttle Actuator Control System — Forced Limited RPM
The TAC monitor caps engine speed at a fixed limp-home rpm because it can no longer trust the throttle response. Driver may notice a hard rev limit well below redline.
Affected components
- Throttle actuator control
- Ecm
Common causes
- High likelihood: Underlying TAC fault triggers rpm cap
- Medium likelihood: Throttle response time out of spec
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
- A drive cycle may be required after repair
- Reduced-power or limp mode may occur
Related codes
Sources
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.