RangeRovers.net Forum banner

21 - 22 of 22 Posts

·
Premium Member
1970-1995 Range Rover Classic
Joined
·
455 Posts
No they didn't, Siemens designed and built the fobs and receivers and supplied them to BMW and Land Rover.
Even better. Do you know which chip it is?
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,198 Posts
Marty, I don't have a p38 key here right now so I have to ask.
I suppose the Information is stored in an EPROM at production, like in the BMW keys.
Do you know which one?

In that case we could do the individual programming wherever we are and we could just order a batch of virgin keys, the blade yet to be cut and the EPROM to be written

That would be extremely helpful to know
I don't have the part number to hand - it's a chip on the underside of the fob PCB when you have the battery cover off, so I'll have to look through pictures etc. But unfortunately you can't purchase virgin keys - they all came from the factory and LR, and I haven't seen any for sale elsewhere - even from the likes of aliexpress/alibaba in China. You can get Disco II keys, as you program the key codes into the BCU, rather than have to have the keys matched to the lockset for the vehicle. I think the D2 also uses a different transmission type, as I bought one to play with to see if it could be adapted.

The code etc isn't actually stored in an EEPROM either - unlike the BECM end. All of the code and the fob ID that it sends the BECM is stored in the main MCU chip in ROM - and these chips are OTP - one time programmable. So without being able to reverse engineer it and be able to dump the code memory, then you wouldn't be able to use new chips (if they are even still available) without being able to program the rest of the code to it aswell. And if it wasn't correct, then your new OTP chip would just be useless until you got it right!

No they didn't, Siemens designed and built the fobs and receivers and supplied them to BMW and Land Rover.
I thought they were made by Huf? That's what some of the RF receivers and bits to do with fobs I've got here have marked on them. Or are they a division of Siemens?

Even better. Do you know which chip it is?
As mentioned above - it's the OTP MCU chip. I can't remember the part number off the top of my head, but it's of the same family as the BECM MCU chip. They're all part of (from memory) the M68HC11 family.

We do have our own code (in a primitive form) to be able to generate and transmit a fob code to the vehicle, and have it work. We just need to find a newer MCU chip that we can use and has low power consumption, and then adapt the code to whatever programming style it requires, as we have used Atmel chips so far, but they look to be a bit too power hungry for a key fob transmitter.
 
21 - 22 of 22 Posts
Top