There are a lot of different opinions on valve adjustments on the 3vze and 5vze motors. If you will Google it you will find a lot of certified Toyota mechanics say to just leave them alone. On my 5vze I could hear one of the valves clicking so I went ahead and adjusted all of them even though my mechanic brother said to just leave it alone.
As for the check engine light coming on I would not just ignore it or tape over it cuz if you get a real check engine code you won't know because the light stays on all the time and that would drive me crazy too.
EDWARD NELSON