Idle Air Control (IAC) Valve
- Start engine. Idle engine for approximately 2 minutes. Turn engine off. Ensure a "clicking" sound is heard from IAC immediately after stopping engine.
- Disconnect IAC valve connector. Using a DVOM, check resistance between terminals specified in IAC VALVE RESISTANCE table. See Fig 1. If resistance is not as specified, replace IAC valve.IAC VALVE RESISTANCE
Terminals Ohms B1 & S1 Or S3 10-30 B2 & S2 Or S4 10-30 NOTE: Wait approximately 20 seconds or longer before disconnecting negative battery cable after ignition is turned off. - Disconnect negative battery cable. Drain engine coolant. Disconnect IAC valve connector. Disconnect air hose and 2 water by-pass hoses from IAC valve.
- Apply battery voltage between IAC valve terminals B1 and B2. Repeatedly ground IAC valve terminals S1, S2, S3 and S4 in sequence. See Fig 1. Ensure IAC valve moves toward closed position.
- With battery voltage applied to IAC valve, repeatedly ground IAC valve terminals S4, S3, S2 and S1 in sequence. See Fig 1. Ensure IAC valve moves toward open position. If operation is not as outlined, replace IAC valve.