Why is control indicator light comes on (engine)? Who could share on this ?

Doesn't this light sometimes just come on when it is time for routine maintenance? Of course, there could be some other reason. How is your car driving?

It might mean it's time for routine maintenance, or it might lead to something serious. I suggest getting it checked out right away.

Note: often, if you get your car checked out by an independent garage instead of the dealer, the light will remain on even after maintenance. This is because the dealer is the only one who can turn the light off. I don't know if this is true of the Sienna, but ask whomever you take it to.