The accelerator pedal position (APP) sensor is a potentiometer that provides a signal to the PCM proportional to the accelerator pedal position. This sensor is only on models equipped with the 7.3L DIT diesel engine. The 7.3L DIT diesel engine incorporates a "drive by wire" system in which there is no cable to open the throttle plate. The APP sensor sends a signal to the PCM and the PCM control the air/fuel mixture accordingly. The accelerator pedal position sensor acts similar to the TP sensor on a gasoline engine. It provides the input to the PCM directly proportional to the engine load.
The accelerator pedal position sensor is tested just like the throttle position sensor. See throttle position sensor for testing.
REMOVAL & INSTALLATION
The accelerator pedal position sensor is not serviced separately. If the accelerator pedal position sensor is bad, replacement of the pedal and shaft assembly is required.