Circuit Description

WARNING: This page is about a different car, the 2002 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.

Idle speed is controlled by Electronic Throttle Control System (ETCS). Description of ECTS components are as follows:

Throttle motor is used to operate throttle valve.
Magnetic clutch is used to connect throttle motor with throttle valve.
Throttle position sensor is used to detect opening angle of throttle valve.
Accelerator pedal position sensor is used to detect accelerator pedal position.
Engine Control Module (ECM) controls ETCS.

DTC is set when idle speed continues to vary greatly from target speed. Possible causes are:

Defective ETCS.
Leaking air induction system.