The check engine light may or may not reset, depending on what the problem is. The message block suggests where he might look. For example at this time mine tells me that I have a light out. It is up to me to find it, but when I fix it the light will go away.

The oil drain plug is on the back side of the sump toward the rear (lefthand end) of the engine. 14mm? 17mm? Something with a small head.