Wastegate Actuator: Description and Operation

The stepper motor is rotated by voltage pulse sent to it by the TCS controller. The stepper motor is able to rotate 90 degrees, depending on the number of pulses it receives from the TCS controller. A micro switch inside the stepper motor unit tells the TCS controller when the stepper motor is at a zero degree angle.
250 pulses from the TCS controller are required to move the stepper motor 90 degrees.