Accelerator Pedal Position Sensor
The accelerator pedal position (APP) sensor allows the engine control module (ECM) to determine the driver requests for vehicle speed, acceleration and deceleration. The engine control module (ECM) uses this information, together with information from the anti-lock brake system (ABS) module and the transmission control module (TCM), to determine the setting of the electronic throttle.
Three screws attach the accelerator pedal position (APP) sensor and integrated accelerator pedal to a bracket on the lower dash panel. A six pin electrical connector provides the interface with the vehicle harness.
The accelerator pedal position (APP) sensor is a twin track potentiometer. Each track receives an independent power supply from the engine control module (ECM) and returns an independent analog signal to the engine control module (ECM). 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 engine control module (ECM) adopts a limp home mode, which limits the engine speed to 2000 rev/min maximum.
The engine control module (ECM) constantly checks the range and plausibility of the two signals and stores a fault code if it detects a fault.