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 Valve (PRIZM)
Idle Air Control (IAC) valve is located on bottom of throttle body. IAC valve opens and closes air by-pass passage according to signal from PCM. When open, air is supplied to intake manifold, which increases engine RPM for different engine loads. A malfunction in IAC valve circuit can set DTC P0505. For test procedure with DTC set, see appropriate SELF-DIAGNOSTICS article.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.