With used Toyota Certified Prius's starting to turn up with more than 36,000 miles (i.e., factory warranty has expired), is it possible to extend the 3,000-mile comprehensive warranty that comes with a 'certified used Toyota'? Toyota.com : Toyota Certified Used Vehicles Extending the comprehensive warranty to at least one year or 10,000 miles- is likely worth a few hundred dollars to alleviate the concerns some of us have with buying a used higher mileage car.