Circuit Description
WARNING: This page is about a different car, the 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
Battery positive voltage is supplied to terminal +BM of ECM even when ignition switch is off for electric throttle control system. If malfunction is detected, ECM shuts down power for throttle motor, and throttle valve is fully closed by return spring. Throttle valve is locked at a certain opening angle. Also, entire electronically controlled throttle operation is cancelled until system returns to normal and ignition switch is turned off.
DTC is set when there is an open in ETCS power source circuit and/or a faulty ECM.