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.
Circuit Description
Powertrain Control Module (PCM) controls Idle Air Control (IAC) valve in order to regulate air flow through idle air by-pass passage. Amount of air flowing through idle air by-pass passage determines idle speed. PCM directs IAC valve according to changes in engine load. A stalling or poor idle concern could be caused by an IAC valve that is not operating properly.
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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.