From Wikipedia, the free encyclopedia. A certified pre-owned car or CPO is a type of used car. Most often late-model, they differ from other used cars by having been inspected, refurbished, and certified by a manufacturer or other certifying authority.They also typically include an extended warranty, special financing, and additional benefits.rom Wikipedia, the free encyclopedia. A certified pre-owned car or CPO is a type of used car. Most often late-model, they differ from other used cars by having been inspected, refurbished, and certified by a manufacturer or other certifying authority.