Accelerator Pedal Position (APP) Sensor
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2018 Ford Transit-350 HD, 2018 Ford Transit-350, 2018 Ford Transit-250, 2018 Ford Transit-150, and 2018 Ford F-550 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The APP sensor is a 2 track potentiometer that is used to calculate driver demand for power based on the rotation angle of the accelerator pedal. The sensor receives a reference voltage from the PCM and provides a variable voltage signal directly proportional to the accelerator pedal position. The PCM uses the 2 APP sensor inputs to calculate the desired fuel quantity, injection timing, and the correct fuel pressure. A concern with the APP sensor illuminates the powertrain malfunction indicator (wrench). Normal engine operation is permitted if the PCM detects a concern on one of the 2 sensor signals. If the PCM detects a concern on both of the sensor signals, the PCM only allows the engine to operate at idle.