Idle Air Control (IAC) Motor
- Disconnect IAC motor connector. Check resistance between IAC motor connector terminal No. 2 and either terminal No. 1 or 3. Also check resistance between IAC motor connector terminal No. 5 and either terminal No. 4 or 6. Each resistance should be 28-33 ohms at 68°F (20°C). If resistances are not as specified, replace IAC body assembly. If resistances are as specified, go to next step.
- If using lab scope, go to step 4. Engine coolant temperature must be 68°F (20°C) or less. If not, an Engine Coolant Temperature (ECT) sensor that is appropriate temperature can plugged into ECT sensor connector. Turn ignition on (engine off) and listen for IAC motor operation sound. Operational sound should be heard when ignition is turned on and off.
- For testing IAC control circuit, see DTC P0505: IDLE CONTROL SYSTEM MALFUNCTION in appropriate SELF-DIAGNOSTICS article.
- Using test harness, or backprobing, connect lab scope pick-up, in turn, to IAC motor connector terminals No. 1, 3, 4, and 6. With engine running, compare IAC motor waveform to normal waveform. See Fig 1.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.