Join Date: Aug 2007
Location: Staunton, VA - USA
Research Assistance: Mastertech On Board Diagnostics & OBD-II
Based on some recent information I've received it appears that one of our regulars here, who shall remain nameless for the moment, has succeeded in "grafting" a functional OBD-II port on to a "Mastertech Only" car and has done so in a way that does not require any cutting in to existing wiring in the loom.
I am in the process of doing research to try to put together an article on how this is done, but I need further information regarding what diagnostic port or ports appear on cars destined for various markets over various model years.
I believe that either 1990 or 1991 (and I suspect the latter) was the first model year where the Mastertech on board diagnostics became standard equipment on Rolls-Royce and Bentley cars. If I can get anyone with a 1990 and a 1991 car to let me know whether they have a Mastertech port (large, circular port that's hidden behind the knee roll door that covers the fuse board) I would very much appreciate that.
In addition, I would love to know whether or not any other port is mounted beside/near the Mastertech port on your car and, if there is, what model year and delivery market the car comes from.
By the 1996 model year onboard diagnostics that met the OBD-II specification were required by law for all cars sold in the USA. Cars that were sold there have an OBD-II diagnostic port mounted right next to the Mastertech port. I am wondering what other markets, if any, had this port as standard equipment.
The first two attached photos show a yellow port that has a black "connector to nowhere" attached to it that was hidden away up above and behind the Mastertech port on a 1997 Bentley Turbo R that was for the UK market (and, obviously, RHD). The suspicion is that this port, which is the key to the "no cutting necessary" method, is probably hidden in the same way on Mastertech equipped cars from the very beginning that were being delivered to markets where other styles of on-board diagnostic ports were not legally required. By contrast, the third photo shows what was found in a 1996 Continental R that had original delivery to the UAE (or at least that's what I suspect). You'll notice that a slightly different variant on this yellow port and black connector are what end up being used to bridge to a true OBD-II specification diagnostic port.
I'd really like to determine whether these yellow ports are indeed present, even if hidden, on all Mastertech equipped cars. I'd also like to determine when (or for what markets) they transitioned from the smaller square shape shown in the first two photos to the wider format shown in the third.
Any and all assistance with finding the answers to these questions would be greatly appreciated.
The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth. ~ Niels Bohr