Newer vehicles are equipped with a computer that monitors many sensors and devices. If an sensor input to the computer is not right; the computer will turn on the " check engine" light. A OBD tool, plugs into the computer to see what the error is. The OBD tool can also reset, the "check engine" light; after repairs. http://en.wikipedia.org/wiki/On-board_diagnostics
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Newer vehicles are equipped with a computer that monitors many sensors and devices. If an sensor input to the computer is not right; the computer will turn on the " check engine" light.
A OBD tool, plugs into the computer to see what the error is.
The OBD tool can also reset, the "check engine" light; after repairs.
http://en.wikipedia.org/wiki/On-board_diagnostics