What this code means

The Idle Air Control (IAC) valve circuit has a malfunction. The IAC valve controls engine idle speed by regulating the amount of air bypassing the throttle plate.

Symptoms

• Check Engine Light
• Erratic idle speed
• Idle too high or too low
• Engine stalling at idle
• Rough idle

Common causes

• Faulty IAC valve
• Carbon buildup on IAC valve or throttle body
• Wiring issue to IAC
• Vacuum leak affecting idle
• Dirty throttle body

Diagnostic steps

1. Test IAC valve resistance
2. Clean IAC valve and throttle body
3. Inspect IAC wiring and connector
4. Check for vacuum leaks
5. Monitor IAC duty cycle on scan tool (should be 22-65%)

Repair notes

Clean throttle body and IAC valve first. Replace IAC if faulty. Repair vacuum leaks.

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