Accelerator Pedal Position (APP) Sensor
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Ford RV Cutaway, 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
The APP sensor is a 3-track potentiometer that is used to calculate driver demand for fuel quantity. The sensor receives a VREF voltage from the PCM and provides a variable voltage signal directly proportional to the accelerator pedal position.
A detected malfunction of the APP sensor illuminates the electronic throttle control (wrench) indicator. A PCM detected fault on one of the 3 sensor signals permits normal engine operation. A fault with 2 sensor signals only allows the engine to operate at idle.