Thread: Nanocom Evo

I'm looking at a more stable supply for when running in gauge mode rather than updating (since I have a V8). To try to get around the issues I have keeping it on. I have asked the question on BBS forum but no replies.

Feel free to ignore everything I've said on the matter. I just managed to brick my new NNN500030 when the nanocom locked up just prior to the end of the upload.

Oh dear, I'm not rejoicing in your pain there.

It's more of an annoyance as I still have the davis ECU. I thought I'd turned the air con off but noticed half way through the upload it was on. Stupid really. I double checked battery with air con off later and I had 12.4v at the terminals, so it should have been ok otherwise.

I've started a debricking thread. I could really have done without the additional expense but I should be able to resurrect it.

At least you can mod yours, the V8 is stuck with one flavour, Vanilla.

At least have the option of switching capacity tunes in there but no. And I think that if I get a NAS spec ECU to suit the 4.6 that will cause more issues than it solves. Needs extra O2 sensors (not hard but need to make an extra harness) at a minimum. Who knows what else is there.

Having a V8 you don't need to be able to do anything. Us diesel owners need a bit extra.

The NNN series of TD5 ECU's are the first Land Rover used that could support being reflashed in the field and as such they have quite some design flaws and sadly reflashing them is always going to be a risky process.

At the risk of boring some with the technical details, the real problem is that the first thing that has to be done is to completely erase the entire contents of the Flash memory, which not only includes the Map data but also the ECU's entire operating system which also includes all diagnostic communication functionality. At that point in time the ECU is depending soley upon the Diagnostic communication functionality that has been loaded into RAM to download a new operating system into the Flash.

Any failure or interruption, howsover caused to that process, can result in an ECU that does not have a working operating system and so provides no diagnostic communication to provide any ability to retry re flashing it.

Fortunately by that time Land Rover was purchased by Ford who already had the solution to this. So on a Disco 2 you only have the TD5 that can be reflashed albeit at some risk, but on a Disco 3 most ECU's can be reflashed without any risk at all.

The reason for this is Primary and Secondary Boot loader technology.

In essence, before the Operating system is loaded from Flash memory, the ECU's first loads the Primary boot loader from Read Only Memory. This provides at least the very basics of diagnostic communication functionality, even in the event that there is no operating system in flash memory at all.

As a safeguard against some crash or incorrect operation causing some erasing or overwriting of flash contents, the primary boot loader contains no code or flash writing functionality.

So before you can erase and reprogram the Flash memory you have to load the additional code into the ECU's Ram, called the Secondary Boot Loader and execute it. That then gives the additional diagnostic functionality to reflash the Flash memory.

This technological approach means that under any situation the ECU always has enough diagnostic functionality provided by the Primary boot loader to then load in the Secondary boot loader that then allows for re flashing.

Quite Brilliant, however trust Land Rover to find a way screw even this up.

On the Disco 3 and most modern vehicles, the Autobox ECU actually resides inside the Gearbox itself. I am guessing that LR must have had a lot of re flashing failures based upon gearboxes being reflashed when they were too hot.

So they added a pre requisite to the flashing process in their diagnostic equipment that reads the Gearbox temperature before allowing reflashing.
Unfortunately the capability for diagnostically reading the gearbox temperature is only provided in the operating system and not in the primary boot loader, which then takes it all back to the TD5 situation

The fix was apparently to fit a new gearbox ;-(

I hope some of you found this interesting and informative.

Hi Colin,

Do you think it would be worthwhile building a bench rig to flash the ECU? It would eliminate all of the vehicle related variables that cause uploads to fail.

I'm assuming 13.8V supply would be fine as the charging system generates more than this when the engine is running.

cheers
Paul