For safety reasons, the APP sensor is designed as a inductive double sensor.
In this system, the signal from APP sensor 1 is transmitted directly as a pulse width modulated signal to the PCM.
The APP sensor 2 signal is transmitted as an analog signal to the instrument cluster. In the instrument cluster the APP 2 signal is digitized, then put onto the CAN data bus and transferred to the PCM.
Effects of faults
If one of the two sensors of the APP sensor fails, the engine runs at reduced power output. However, it is still possible to reach top speed. If the vehicle is equipped with a driver information system, the fault message: “REDUCED ACCELERATION” is displayed.
If the APP sensor fails completely, the engine is regulated to a speed of up to 1200 rpm after the BPP switch and the stop lamp switch have been actuated once and a plausibility check has been carried out. The vehicle can be accelerated to a maximum speed of 56 km/h.
If the vehicle is equipped with a driver information system the error message “LIMITED MAXIMUM SPEED” is displayed.
If the vehicle is not equipped with a driver information system the “engine system fault” warning lamp illuminates when a system error occurs.