Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Idle Air Control (IAC) Valve
The IAC valve is mounted on the throttle body and controls the amount of by-pass air around the throttle plate. If engine RPM is too low, more air is by-passed around the throttle plate to increase engine RPM. If engine RPM is too high, less air is by-passed around the throttle plate to decrease engine RPM.
When the engine is idling, the proper position of the IAC valve is determined based on battery voltage, coolant temperature, engine load and engine RPM. If the IAC valve is disconnected or connected with the engine running, the IAC valve has to be reset. Reset of the IAC is accomplished by driving the vehicle over 35 MPH with the circuit properly connected.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.