Monitor Description
WARNING: This page is about a different car, the 2005 Toyota Sienna. However, it is still accessible from the selected car via links, so may be relevant.
The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal position sensor has 2 sensors elements/signal output: VPA and VPA2.
VPA is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA. When the difference between the voltage outputs of VPA and VPA2 deviates from the standard, the ECM concludes the accelerator pedal position sensor has a malfunction. ECM turns on the MIL and a DTC is set.