Idle Air Control Solenoid
Idle Air Control (IAC) solenoid is by-pass air type. Ensure ignition is off. Disconnect IAC solenoid harness connector. Measure resistance between IAC solenoid connector terminals. Solenoid has diode and resistance will be infinite if voltmeter is hooked up wrong. If resistance is not 6-13 ohms, replace solenoid. If resistance is 6-13 ohms, IAC solenoid is okay. See TEST KE under SYSTEM TESTS in SELF-DIAGNOSTICS - B2300, B2500, B3000, B4000 & TRIBUTE article for additional testing and specifications.