They don't say. The COPS just tell you that it's dead when you ask about an upgrade:
Bob: We're sorry, but your vehicle has... gone on to a better place.
Curt: We are sorry for your loss.
Max: Can't you fix it?
Bob: We're afraid the car is completely dead! Repairing it is beyond our current skill level.
Bluster Blaster: It still had so much to live for.