Circuit Description
WARNING: This page is about a different car, the 2002 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
Electronic Throttle Control System (ETCS) uses throttle control motor to operate throttle valve. Throttle valve opening is detected by Throttle Position (TP) sensor which delivers input signals to ECM. ECM uses input signals and controls the throttle control motor to provide proper throttle valve opening in response to driving conditions. DTC is set when throttle opening angle varies greatly from target throttle opening angle. If DTC P1129 exists, ECM will turn off the power to throttle control motor and throttle valve is closed by the return spring. When this occurs, throttle valve is controlled by throttle cable connected to accelerator pedal. Possible causes are defective throttle body or ECM.