Circuit Description

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

Acceleratior pedal position sensor is mounted in accelerator pedal to detect opening angle of accelerator pedal. Since this sensor is electronically controlled with hall elements, accurate control and reliability can be obtained. Two sensors are used to detect accelerator position and a malfunction of accelerator pedal position sensor. In accelerator pedal position sensor, voltage applied to pedal terminals VPA and VPA2 of ECM changes between 0-5 volts, in proportion to opening angle of accelerator pedal. Terminal VPA is a signal to indicate actual accelerator pedal opening angle which is used for engine control, and terminal VPA2 is a signal to indicate information about opening angle which is used for detecting a malfunction. ECM judges current opening angle of accelerator pedal from these signals input from terminals VPA and VPA2 and, ECM controls throttle motor based on these signals. DTC is set when the difference between VPA1 and VPA2 exceeds threshold and IDL is off. Possible causes are:

Faulty accelerator pedal position sensor circuit.
Faulty accelerator pedal position sensor.
Faulty ECM.