Why Do They Fail?

Idle Air Control Valves are electro-mechanical components that are subject to:

• Carbon build-up or intake contamination, restricting valve movement

• Electrical faults, including failed solenoids or poor connector continuity

• Wear on the actuator motor or pintle mechanism over time

• Vacuum leaks affecting airflow and idle control

Symptoms of Failure

A failing IACV may cause:

• Erratic idle speed (too high, too low, or fluctuating)

• Engine stalling, particularly when decelerating or stopping

• Difficult cold starting or extended cranking time

• Check Engine Light (MIL) and idle control-related fault codes

• Increased fuel consumption or emissions at idle

Fitting Tips

1. Inspect the throttle body and IACV passage for carbon build-up – clean if necessary before replacement.

2. Avoid over-tightening — many IACVs are plastic-bodied and use fine threads.

3. Check for vacuum leaks or split hoses that could mimic idle issues.

4. Reset idle parameters via scan tool if required for the application.

5. After fitting, allow the ECU to relearn — some vehicles require a drive cycle or manual adaptation.