Pedal request, general
WARNING: This page is about a different car, the 2005 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
Two potentiometers are integrated in the accelerator pedal bracket. Potentiometer 1 provides ECM with information on the driver's torque request in the form of a voltage signal 0-5V.
Potentiometer 2 is a safety potentiometer that provides ECM with information on the pedal position in the form of a voltage signal 0-2.5V. This voltage is used to ensure that information from potentiometer 1 is reliable.
If the information from the potentiometers does not agree, one of them must be malfunctioning. The engine throttle control will then go into limp-home mode.