Idle Speed Control (ISC) Motor Test

Idle Air Control Motor Circuit:

COMPONENT TEST
Use a stethoscope to check if the sound of the idle air control motor operating can be heard immediately after the ignition switch is turned to ON.

HARNESS TEST

1. Check for open or short circuits between terminal 5 of the Idle Air Control motor and terminal 4 of the engine control module.
2. Check for open or short circuits between terminal 6 of the Idle Air Control motor and terminal 17 of the engine control module.



If the ISC Motor Position Sensor (steps) are outside of the normal range, check the following:

1. Incorrect basic idle speed adjustment.
2. Dirt or deposits stuck to the throttle blade.
3. Vacuum leak between the throttle body and the engine.
4. EGR valve not fully seated.
5. Mechanical malfunction within one or more cylinders.