Circuit Description

The ECM controls the throttle motor which opens and closes the throttle valve. The opening angle of the throttle valve is detected by the throttle position sensor. It provides feedback to the ECM to control the throttle motor to control the throttle valve opening angle properly in response to the driving condition. If a malfunction is detected, the ECM shuts down the power for the throttle motor, and the throttle valve is fully closed by the return spring. The throttle valve is locked at a certain opening angle. The whole electronically controlled throttle operation is cancelled until the system returns to normal and the ignition switch is turned OFF.