Accelerator Pedal Position Sensor
The Accelerator Pedal Position (APP) sensor is located on the accelerator pedal. The APP sensor comprises a plastic housing which contains 2 potentiometers and an analogue/digital converter. The potentiometers are connected to a common shaft which is actuated by movement of the accelerator pedal.
The Powertrain Control Module (PCM) uses the analogue sensor and the Pulse Width Modulation (PWM) signal information. The PCM calculates from the signal values the required position of the butterfly valve in the electric throttle. The PCM then operates the motor in the electric throttle to move the butterfly valve to the correct angle in relation to the pedal position.
In the event of a failure of the PWM signal, the PCM uses the analogue signal received from the Body Control Module/Gateway Module (BCM/GWM) as a replacement. If the analogue signal is also incorrect or missing, the PCM limits the maximum engine speed to 2, 000 Revolutions Per Minute (RPM).
The PWM and the analogue signal are used for diagnosing faults with the APP sensor. If the PCM detects a difference between the analogue and PWM signals a Diagnostic Trouble Code (DTC) is stored. The PCM will use the signal with the lowest value for electric throttle control. The APP sensor position and any stored fault DTCs can be read using the Jaguar Land Rover (JLR) approved diagnostic equipment.