Circuit Description
WARNING: This page is about a different car, the 2002 Lexus GS 430. However, it is still accessible from the selected car via links, so may be relevant.
ETCS is composed of throttle control motor, electromagnetic clutch, Throttle Position (TP) sensor, accelerator pedal position sensor, ECM and throttle body. If DTC P1633 is set, ECM shuts down power to throttle control motor and electromagnetic clutch. DTC P1633 is set when ECM malfunctions. Possible cause is; faulty ECM.