When the ignition is first turned on a click noise is heard from under the hood of a vehicle equipped with ETC. Technician A says that this is the normal operation of the ETC self-test. Technician B says that the TAC motor should not move unless the engine is running. Which technician is correct?

Technician A says that this is the normal operation of the ETC self -test is the correct answer.

Explanation:

An engine control unit (ECU), also widely referred to as an engine control module (ECM), is a type of electronic control device that controls an internal combustion engine with a series of actuators to ensure maximum engine performance.

It achieves so by reading values from a multitude of sensors within the engine bay, translating data using multidimensional feedback maps (the so-called lookup tables) and modifying the actuators.

Mechanically fixed and dynamically regulated by mechanical and pneumatic means, air-fuel combination, ignition time, and idle speed were before ECUs.

As soon as the system gets battery voltage, after ignition is turned, the efi computer makes a self-test of all the actuators and sensors, included the ETC.