Idle Air Control (IAC) Valve (Except 9000 Series Turbo)
- Start engine, turn air conditioning on, and observe whether idle speed increases when A/C clutch engages.
- If no increase occurs, leave ignition on. Ensure battery voltage is available at pin No. 2 (Blue/Red wire) on IAC valve.
- Turn ignition off. Unplug connector from IAC valve. Measure resistance between pins No. 1 and 2 and between pins No. 2 and 3 on IAC valve. Resistance should be 10-15 ohms for each measurement. If IAC valve is okay, go to next step. If resistance is not as specified, replace IAC valve with known good unit. Recheck idle.
- With ignition off, inspect Blue/White wire between IAC valve connector and pin No. 33 on fuel injection ECM for open or short circuit. Repair wire if defective.
- With ignition off, inspect Gray/Red wire (900 Series) or Green/Gray wire (9000 Series) between IAC valve connector and pin No. 15 on fuel injection ECM. Repair wire if it is shorted or open.