Hi Rob, I can confirm that the Rover Mk3 nav drives are firmware locked and can't be updated.
For more information about TMC, have a look at this post I made some years ago.....
1) What is TMC?
TMC or Traffic Message Channel is a system which allows real-time traffic data to be sent to the vehicle's Navigation system and enables the driver to see via on screen symbols and voice announcements if there are any hold ups, accidents, closed roads, high-winds etc, and where applicable, offers alternative routes to avoid the problem.
2) Who operates the system, and how much does it cost?
In the UK, a company called "itis Holdings PLC", owns the licence and collates the data required to make the system work. The data is sent out via The Classic FM frequency(although it can't be heard), and as such can be received nationally throughout the country.
itis Holdings sell the licence to use the system to car manufacturers, and as a result there is no cost to the end user (ie) it is free.
Currently the following car makers have a licence to use the system: BMW, Ferrari, Ford, Land Rover, Lexus, Toyota, Mercedes, Mini, Subaru, Nissan, Porsche, Renault, Saab, Vauxhall, Volvo and Maserati.....NOT MG ROVER !!!!
3) How can I get TMC to work in my Rover 75 / ZT?
As you can see from the list, BMW can use the TMC functionality in their cars, and of course our Sat Nav systems are the same as those used in BMWs so by default we should all be able to have the system, however, in practice most owners only get the small black TMC letters at the foot of their screens and "function not available" in the menu. This is because in order to make the system active, the correct Map Disc has to be used which includes on it the extra TMC data codes to convert what the Sat Nav receives from Classic FM into symbols & voice announcements.
The official MG Rover Map CDs were originally supplied by "Navteq", and as Rover had not paid itis for the licence, all Navteq discs came WITHOUT the TMC codes on them. (Some discs would have the TMC logo on the front, but that just meant it would work in continental Europe, not here in the UK.
However, if you are prepared to splash out a little more you can get the TMC encoded Map CDs from a company called "VDO/Dayton". These discs have on them, all the codes needed to make the system work.
A Word Of Warning:
The Rover 75 / ZT was fitted with 2 types of Navigation Computer, the original unit known as a Mark 2 looks like this:
and I have found that when a TMC map disc was used in one of these, it caused the Sat Nav to crash frequently. This may be because the early units were produced from 1999 onwards, but itis's TMC system with BMW didn't come about until 2002, and so the the hardware may not have been compatible with their code data. (or perhaps this was just an isolated anomaly with the old mark 2 I was using - although it worked perfectly with a non TMC disc)
The other type of navigation computer, fitted from late 2001 onwards was the Mark 3
And this unit has no problems using TMC enabled discs.
4) So what do you get for your money and how does it look?
Once a TMC disc is inserted, the little TMC letters on the Hi-Line Sat Nav screen will turn from Black to Green. The system has to "borrow" the radio tuner and finds Classic FM automatically if you aren't using it at the time so you don't have to listen or even have it switched on. Otherwise the only radio station you can listen to if you want it to work is Classic (you can always use the CD player or Tape deck)
Once you have set a destination, the map screen will show any traffic incidents as symbols, with a large scale like this:
or if closer like this......and they appear in Red if they lie on your path of travel
When an incident is received, the voice announcement will say something along the lines of "Attention in 12 miles, stationary traffic", it will also show you the distance to the problem, how many miles the problem lasts for, and the distance remaining before your last opportunity to turn off to avoid it......
Also, where available, it will offer you a diversionary route to avoid the problem, just select the red "Diversion" option....
Black arrows appear along the route to show you the direction and length of the affected area.....
You can select from the menu, what items you want the TMC to alert you to, and which you would rather it ignore........
Finally, here is a list of the TMC symbols that you might encounter, and what they mean. (I haven't seen all of these myself though)
