Monitor Description

The throttle motor is operated by the ECM and it 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 so that the ECM can control the throttle motor and the throttle valve opening angle properly in response to driver inputs.

The ECM determines the "actual" throttle angle based on the throttle position sensor signal. The "actual" throttle position is compared to the "target" throttle position commanded by the ECM. If the difference of these two values exceeds a specified limit, the ECM interprets this as a malfunction in the ETCS. The ECM turns on the MIL and a DTC is set.

If the ECM judges that the ETCS is malfunctioning, 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 certain operating angle. At the same time, operation of the ECTS is cancelled until the system returns to normal or the ignition switch is turned OFF.