Some used car buyers are attracted to newer used vehicles that have factory warranty remaining (this is different from any type of a used car Dealers warranty.) Generally there are three sources for used vehicles with remaining original factory warranty: rental vehicles, leased vehicles, and individual owners that trade their vehicles in before the warranty expires.
Be cautious, these newer previously pre-owned vehicles have a higher than average chance of odometer tampering and/or accident damage which will void their warranty. Manufactures are now taking an aggressive approach to refuse warranty claims leaving the current owner to pay for repairs. Many used car buyers are shocked to find out the remaining factory warranty has been voided.
If you are buying a used vehicle with remaining factory warranty - have it professionally inspected for odometer tampering, previous accident damage, abuse and misuse, all of which can be grounds for voiding any remaining warranty. Determining the true condition of a used vehicle before purchase is the responsibly of the buyer.