The car engine of injection between years 1990 and 2008 have a valve to control the idle speed. This valve is called IAC (Idle Air Control) or commonly called stepper motor.
This valve is a common fail cause.
The car engine of indirect injection have coil based injectors, they split in two big groups: High and Low impedance.
This device can test the steppers like Magnetti Marelli, GM steppers, PWM IACs of single coils and up to 1 high impedance Injector.
Manufactured for hard work, with a high endurance.
Is a elemental tool for any modern mechanic and avanced users.
1)Press the MODE button until turn on MM led.
2)The right and left buttons open and close the stepper
3)If press both side buttons at same time will start an automatic opening and close cycle.
This motor is a stepper of double-coil stepper motor with polarity reversal.