Throttle Plate Position Controller (TPPC) Outputs

The Electronic Throttle Body uses a DC motor to control the throttle plate. An internal spring is used to return the throttle plate to a default position. The default position is typically a throttle angle of 7 to 8 degrees from the hard stop angle. The closed throttle plate hard stop prevents the throttle from binding in the bore. This hard stop setting is not adjustable and is set to result in less airflow than the minimum engine airflow required at idle.

The purpose of the TPPC is to control the throttle position to the desired throttle angle. The current ETC systems have the eTPPC function integrated in the main PCM processor. The desired angle is relative to the hard-stop angle. The hard-stop angle is learned during each key-up process before the main CPU requests the throttle plate to be closed against the hard-stop. The output of the (e)TPPC is a voltage request to the H-driver (also in PCM). The H driver is capable of positive or negative voltage to the Electronic Throttle Body Motor.