A "J-Body" or "J-car" is any of General Motors J-platform vehicles. These include:
Buick SkyHawk
Cadillac Cimarron
Chevrolet Cavalier
Oldsmobile Firenza
Pontiac Sunfire, Sunbird and J2000
Toyota Cavalier
All of these vehicles, while appearing distinctly different from each other, share a common frame and body layout.
If you look at the fourth digit of the vehicle identification number (VIN) of any J-Body, you will find the letter "J" (surprise, surprise!).
GM uses a different letter to designate each platform it builds vehicles on, for example:
F: Camaro, Firebird.
N: Grand Am, Malibu, Alero
W: Grand Prix, Impala
Y: Corvette
Contrary to seemingly popular belief in some tuner circles that the J stands for "Junk", according to GM it is merely the platform designation - it doesn't actually stand for anything.
