Idle Air Control System Circuit Low
The control line to the idle air control valve - which opens a small bypass around the throttle to set idle airflow - is shorted to ground or measures a voltage below the plausible level.
Affected components
- Idle air control valve
- Iac wiring
Common causes
- High likelihood: Control line shorted to ground
- Medium likelihood: IAC solenoid internally shorted
- Low likelihood: Connector pins corroded - high contact resistance
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
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.