Excuse me, what does the stepping motor on the car mean?

Stepper motor is what we often call idle motor.

Idle motor is generally used for cable accelerator, because the cable accelerator is controlled by the cable of the accelerator pedal and the opening of the accelerator pedal, so it is necessary to use idle motor to control the idle speed when the vehicle is idling. With the development of vehicle technology, electronic throttle has been used, so the idle motor will be gradually eliminated, and the electronic throttle can control the throttle opening through the controller.

Working principle of idle motor: the idle motor controls the idle air intake and is not controlled by the throttle opening. When the throttle valve is completely closed, the air intake at idle speed is completely controlled by the idle motor.