Idle Air Control System Malfunction
A general fault has been detected in the idle air control (IAC) system. On older vehicles with a separate IAC valve, this means the valve cannot maintain commanded idle RPM; on drive-by-wire systems, the equivalent fault is in the throttle body's idle adaptation.
Affected components
- Idle air control valve
- Throttle body
Common causes
- High likelihood: IAC valve carboned, sticky
- Medium likelihood: Throttle body dirty (drive-by-wire)
- Medium likelihood: Vacuum leak affecting idle
Possible symptoms
- Check engine light on
- Idle speed too high, too low, or unstable
- Possible stalling at idle or after cold start
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
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.