Accelerator Pedal Position (App) Sensor

WARNING: This page is about a different car, the 2017 Jaguar XJ, 2016 Jaguar XJ, 2015 Jaguar XJ, 2014 Jaguar XJ, and 2013 Jaguar XJ. However, it is still accessible from the selected car via links, so may be relevant.

The Accelerator Pedal Position (APP) sensor allows the ECM to determine the driver requests for vehicle speed, acceleration and deceleration. The ECM uses this information, together with information from the ABS control module and the Transmission Control Module (TCM), to determine the setting of the electric throttle.

Three bolts attach the APP sensor and integrated accelerator pedal to a bracket on the lower instrument panel. A six pin electrical connector provides the interface with the vehicle harness.

The APP sensor is a twin track potentiometer. Each track receives an independent power supply from the ECM and returns an independent analog signal to the 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 ECM adopts a limp home mode, which limits the engine speed to 2000 rev/min maximum.

The ECM constantly checks the range and plausibility of the two signals and stores a fault code if it detects a fault.