Circuit Description
The Electric Throttle Control System (ETCS) is composed of a throttle motor that operates the throttle valve, a throttle position sensor that detects the opening angle of the throttle valve, an accelerator pedal position sensor that detects the accelerator pedal position, and the ECM that controls the ETCS system.
The ECM operates the throttle motor to position the throttle valve for proper response to driver inputs. The throttle position sensor, mounted on the throttle body, detects the opening angle of the throttle valve and provides this signal to the ECM so that the ECM can regulate the throttle motor.
If the ECM determines that the ETCS system has a malfunction, it shuts off the power to the throttle motor, the throttle valve is closed by the return spring, and the throttle valve is locked at a small opening angle. At the same time, operation of the ETCS is cancelled until the system returns to normal and the ignition switch is turned off. The ECM will turn on the MIL and a DTC is set.