Idle Air Control (IAC) Motor: Notes

CAUTION: DO NOT apply more than 6 volts to IAC motor.

NOTE: For diagnosis and testing information concerning IAC motor position sensor, see appropriate TESTS W/CODES article below.

Using a stethoscope, listen for operating sound of IAC motor when ignition switch is placed in ON position. If no operating sound can be heard, proceed with following tests.
This step checks for continuity between IAC motor and PCM. Disconnect IAC motor harness connector and PCM harness connector. See POWERTRAIN CONTROL MODULE (PCM) LOCATION table under COMPUTERIZED ENGINE CONTROLS. Connect a jumper wire between PCM harness connector terminal No. 4 and vehicle ground. See Figure. Using DVOM, check continuity between IAC harness connector No. 5 and vehicle ground. See Fig 1.
Move jumper wire to PCM harness connector terminal No. 17 and vehicle ground. Using DVOM, check continuity between IAC harness connector No. 6 and vehicle ground. If continuity does not exist, check and repair appropriate circuit. If continuity exists, go to step 4).
If preceding tests do not show any system or component malfunction and PCM is suspected, replace PCM and retest system.

Fig 1: Identifying IAC Motor Connector (Except Galant)
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA

NOTE: Procedures are provided by manufacturer for component testing using an engine analyzer with oscilloscope capability. Refer to manufacturer's operation manual for instructions in use of oscillo-scope. Go to step 8) for test procedures using oscilloscope.