Throttle Plate Position Controller (TPPC) Outputs

The purpose of the TPPC is to control the throttle position to the desired throttle angle. It is a separate chip embedded in the PCM. The desired angle is communicated from the main CPU via a 312.5 Hz duty cycle signal. The TPPC interprets the duty cycle signal as follows:

• 0% <= DC < 5% - Out of range, limp home default position.
• 5% <= DC < 6% - Commanded default position, closed.
• 6% <= DC < 7% - Commanded default position. Used for key-on, engine off.
• 7% <= DC < 10% - Closed against hard-stop. Used to learn zero throttle angle position (hard-stop) after key-up.
• 10% <= DC <=92% - Normal operation, between 0 degrees (hard-stop) and 82%, 10% duty cycle = 0 degrees throttle angle, 92% duty cycle = 82 degrees throttle angle.
• 92% < DC <= 96% - Wide Open Throttle, 82 to 86 degrees throttle angle.
• 96% < DC <= 100% - Out of Range, limp home default position.

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 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.