Originally Posted by Vetteman61
OBDII is the type of computer used to hook up to the car to diagnose when a check engine light code comes up. That is what the OBDII pertains to. To my knowledge they switched to this type at one time and a certain year of car either would be an OBDII or it would not. I don't think they had a year where some were and some weren't, but I could be wrong.
Only the 96 can use the OBDII computer just like all car after that date, I have the factory service manuel for the 91 and 96 caprice.Also the 96 has sensors before and after the cat converters.