Accelerator Pedal Position (APP) Sensor

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

The APP sensor is located on the accelerator pedal. The sensor comprises a plastic housing which contains two potentiometers and an analog/digital converter. The potentiometers are connected to a common shaft which is actuated by movement of the accelerator pedal.

The APP sensor receives a fused 12V supply from the ignition relay in the CJB. The sensor provides two outputs; the analog output is transmitted directly to the CJB, which in turn issues the signal to the ECM on the CAN bus, the second output is the PWM signal which is transmitted directly to the ECM. Both the analog and PWM signals transmit the same positional information.

The ECM uses the analog sensor and the PWM sensor information to calculate the required position of the throttle disc in the electric throttle body. The ECM then actuates the motor in the electric throttle assembly to move the throttle disc to the correct angle in relation to the pedal position.

In the event of a failure of the PWM signal, the ECM uses the analog signal received from the CJB as a replacement. If the analog signal is also incorrect or missing, the ECM limits the maximum engine speed to 2000 rpm.

The PWM and the analog signal are used for diagnosing faults with the APP sensor. If the ECM detects a difference between the analog and PWM signals a fault code is stored. The ECM will use the signal with the lowest value for electric throttle control. The APP sensor position and any stored fault codes can be read using a Jaguar approved diagnostic system.