Circuit Description

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Electric Throttle Control System (ETCS) is composed of the throttle motor to operate the throttle valve, the throttle position sensor to detect the opening angle of the throttle valve, the accelerator pedal position sensor to detect the accelerator pedal position, the ECM to control the ETCS and the one valve type throttle body. ECM controls the throttle motor to make the throttle valve opening angle properly in response to driving condition. The throttle position sensor, which is mounted on the throttle body, detects the opening angle of the throttle valve, and it provides feedback to the ECM to control the throttle motor. If the ETCS has a malfunction, the ECM shuts down the power for the throttle motor and the throttle valve is locked at a certain opening angle. However, the opening angle of the throttle valve can be controlled by the accelerator pedal through the throttle cable.

DTC is set when throttle opening angle continues to vary greatly from target throttle opening angle. Possible causes are:

Faulty electric throttle control system.
Faulty ECM.