What car brand is ET?

ET is not a car brand. I am a car enthusiast. What you mean by ET should be the abbreviation of electronic throttle in automobile.

In order to improve the driving force, ride comfort and economy of automobiles and reduce emission pollution, various electronic throttles with good control characteristics and their corresponding electronic control systems have been introduced by major automobile manufacturers in the world, and electronic throttle control systems (ETCS) have been formed. The electronic throttle control system can accurately control the throttle opening, which can not only improve fuel economy and reduce emissions, but also make the system respond quickly and obtain satisfactory handling performance. On the other hand, it can realize the integration of idle speed control, cruise control and vehicle stability control and simplify the structure of the control system.

I hope I can help you. Thank you!