The used car lemon law declares that a car is a "lemon" if it has required four or more repairs during the warranty period or has been unusable for 30 days during that time. The exact specifications differ by state, but a lemon warrants refund or replacement from the dealer.
One aspect of the lemon law in most states is that the consumer gets to decide whether to take the refund or ask for a replacement vehicle, giving more benefit to the buyer. In some states, it only takes one defect to qualify the car as a lemon, as long as that defect could result in a severe injury or compromise the safety of the vehicle.
In some cases, if a consumer has to hire an attorney to pursue a lemon law claim, the attorney also goes after the manufacturer for his fees, accepting the case on a contingency basis. It is important to check the specific lemon laws in the applicable state, though, as the time frames for filing a claim often differ, and the specific remedies available to consumers can also be different. Websites such as LemonLawAmerica.com offer links to the particular lemon law rules for each state.