Accelerator Pedal Position Sensor
The Accelerator Pedal Position (APP) sensor allows the Powertrain Control Module (PCM) to determine the driver requests for vehicle speed, acceleration and deceleration. The PCM uses this information, together with information from the Anti-lock Brake System (ABS) control module and the Transmission Control Module (TCM), to determine the setting of the electric throttle.
There are 3 screws that attach the APP sensor and integrated accelerator pedal to a bracket on the lower instrument panel. A 6 pin electrical connector provides the interface with the vehicle wiring harness.
The APP sensor is a twin track potentiometer. Each track receives an independent power supply from the PCM and returns an independent analog signal to the PCM. Both signals contain the same positional information, but the signal from track 2 is half the voltage of the signal from track 1 at all positions.
If both signals have a fault, the PCM adopts a limp home mode, which limits the engine speed to 2000 Revolutions Per Minute (RPM) maximum.
The PCM constantly checks the range and plausibility of the 2 signals and stores a fault code if it detects a fault.