is there a diagnostics for RR similar to VAGCOM?
Interesting question, and one i feel, albeit at the risk of boring some, able to shed some light on for the benefit of anyone who may interested to learn.
VAGCOM is really unique in the world of Diagnostic equipment. It's a freely, to very low cost, availiable bit of software that like many other generic OBDII software, simply requires a relatively cheap ISO 1941 interface / OBDII lead.
But where generic OBDII software only really covers some Engine Managements. VAGCOM covers most ECU's on a VAG vehicle, and although i have not used it myself, i understand it's really rather good.
Not surprisingly, many wonder why such a cheap and availaible full coverage system such as VAGCOM or indeed generic OBDII equipment is not so readily availaible for full coverage of other marques like Land Rover.
I will try my best to explain why this is.
Back in the early 90's, CARB (the Californian Air Research Board) had a big smog and pollution problem, primarily caused, as they saw it, by badly maintained vehicles.
In investigating further, they discovered that each manufacturer had a their own monopoly going in respect of maintainence and diagnostic access to all their vehicles on board systems.
They set to and Penned "OBD" a common published industry standard for 3 communication protocols and the data format to be transported over them, and while they payed particular attention to any emmision related aspects their OBD communications standard was actually designed such that it could be applicable to all vehicle ECU's. This BTW is also where the service reminder function we all know and love also came into being.
They managed to get legislation passed for it, to effectively force all vehicle manufacturers who wanted to sell vehicles over there to make their vehicles comply, but only in respect of the emmisions elements. The rest, ie all access to all other ECU's and data was up to each manufacturer.
It seems however that only VAG decided to make all the rest of their vehicle ECU's freely follow the OBD design format.
Most other manufacturers, implimented only the minimal level of OBD emiision related access legislated for, and in some cases produced complient ECU's only for the NAS market. So now you know why some can get a generic OBDII scanner to work and others can't on same year vehicles.
Even on those ECU's that comply, there is often two access modes, one using the legislated and documented &H33 OBD address and the other some undocumented and top secret manufacturer only one.
But even on an ECU using the same protocol (most don't even do that) and if you knew the address, the manufacturer typically employs a sophisticated anti access rolling code type algorythm you have to figure out and pass to gain any access at all and even then everything you can access is all per manufactur top secret.
That's why writing software for accessing just OBD data or indeed entire VAG vehicles, as VAGCOM does, is so very easy and cheap to do, you just read everything you need to know from a published book.
And of course that's also why writing software for entire Land Rover vehicles is so comparitively costly and expensive to do.
OBD has long since been amended to OBDII and adopted in Europe as EOBD and now incorporates other protocols such as CAN.