Accelerator Pedal Position (APP) Sensor
WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal on diesel applications. The APP detects the position of the accelerator pedal and sends this information as a voltage signal to the PCM. The PCM uses APP information to help determining line pressure, shift scheduling and Torque Converter Clutch (TCC) operation. Failure of this sensor will cause the transmission to operate at higher line pressure to avoid damage to the transmission. This higher line pressure causes harsh upshifts and harsh engagements.