Accelerator Pedal Position Sensor: Description and Operation

ENGINE CONTROL COMPONENTS

Accelerator Pedal Position (APP) Sensor
There are two pedal position signals in the sensor. Both signals, APP and APP2, have a positive slope (increasing angle, increasing voltage), but are offset and increase at different rates. The two pedal position signals make sure the powertrain control module (PCM) receives a correct input even if one signal has a concern. The PCM determines if a signal is incorrect by calculating where it should be, inferred from the other signals. If a concern is present with one of the circuits the other input is used. There are two reference voltage circuits, two signal return circuits, and two signal circuits (a total of six circuits and pins) between the PCM and the APP sensor assembly. The pedal position signal is converted to pedal travel degrees (rotary angle) by the PCM. The software then converts these degrees to counts, which is the input to the torque based strategy. For additional information, refer to Torque-Based Electronic Throttle Control (ETC).