Accelerator Pedal Position Sensor: Description and Operation

Accelerator Pedal Value Sender:

Accelerator Pedal Arrangement:

PURPOSE
Pedal position information is supplied to the Electronic Throttle Control (EML) control unit by the accelerator pedal position sensor.

Pedal Value Sender:

OPERATION
The pedal position sensor contains a potentiometer, monitoring switch, and an external safety circuit switch. The potentiometer (voltage divider) of the pedal position sensor divides a 5 volt reference voltage (from the EML), indicating the angle of rotation. This partial voltage is fed back to the EML where the analog signal is converted into digital "angle" degrees. The valid angle range is from -4.7° to +87°.

The EML control unit performs a switching range check in that it compares the switchon point of the switch (approx. 9 deg.) with the angle setting of the Pedal Value Sender (PWG) potentiometer. If the EML control unit finds that the deviation is too great, the output is limited and the EML warning lamp lights.

A kick-down switch integrated in the pedal position sensor (PWG) is used for detecting "kick-down disengaged" in vehicles with automatic transmission. The switch closes at approx. 74 deg.

The switch for the external safety circuit opens at approx. 2.5 deg. The switch output is connected in series with a diode and arranged externally.