Circuit Description

WARNING: This page is about a different car, the 2003 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

The throttle position sensor is mounted in the accelerator pedal to detect the opening angle of the accelerator pedal. Since this sensor is electronically controlled with hall elements, accurate control and reliability can be obtained. Two sensors are used to detect the accelerator position and a malfunction of the accelerator pedal position sensor. In the accelerator pedal position sensor, the voltage applied to pedal terminals VPA and VPA2 of the ECM changes between 0-5 volts, in proportion to the opening angle of the accelerator pedal. The VPA is a signal to indicate the actual accelerator pedal opening angle which is used for the engine control, and the VPA2 is a signal to indicate the information about the opening angle which is used for detecting a malfunction. The ECM judges the current opening angle of the accelerator pedal from these signals input from terminals VPA and VPA2 and, the ECM controls the throttle motor based on these signals. DTC is set when difference between VPA and VPA2 is out of threshold for more than .5 seconds. See Figure-Figure . Possible causes are:

Accelerator pedal position sensor.
VCPA circuit open.
VPA circuit open or ground short.
EPA circuit open.
VPA and VPA2 circuit are shorted.