How do I find out if car engine light was turned off? What do I do if it was?

Even an "as is" sale does not excuse a dealer from informing you of all material facts which it knew prior to engaging in the sale.   Intentional misrepresentation is established by three factors: (1) a false representation that is made with either knowledge or belief that it is false or without a sufficient foundation, (2) an intent to induce another's reliance, and (3) damages that result from this reliance.   With respect to the false representation element, the suppression or omission “ ‘of a material fact which a party is bound in good faith to disclose is equivalent to a false representation, since it constitutes an indirect representation that such fact does not exist.' ” Nelson v. Heer, 123 Nev. 217, 226 (2007). Now on the question of them telling you that the car was "fixed and good", there is an exception to misrepresentation claims which is that a seller, which is that you would be required to introduce evidence to establish that the Dealer knew or should have known that prior damage, which was repaired, was material factor that you as a purchaser would have considered when purchasing the vehicle.  Id.  Because misrepresentation claims require a heightened standard of proof, you should have an attorney go over all of your documents and determine your best course of action.