Yes, FAULTS is a Scrabble word!

Letter values in Scrabble US: F 4, A 1, U 1, L 1, T 1, S 1.

Is it a valid word?

FAULTS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a wrong action attributable to bad judgment or ignorance or inattention
an imperfection in an object or machine
the quality of being inadequate or falling short of perfection
(geology) a crack in the earth's crust resulting from the displacement of one side with respect to the other
(electronics) equipment failure attributable to some defect in a circuit (loose connection or insulation failure or short circuit etc.)
responsibility for a bad situation or event
(sports) a serve that is illegal (e.g., that lands outside the prescribed area)

Also: geological fault.