Xantia - Central locking ECU questions

[lancia58]

Hi Jim

When programming a key the CPH transmits to the key the RF code and the key stores it on a none volatile memory , or the key transmits its factory programmed RF code to the CPH and from now on the CPH allows that key to lock/unlock the doors ?

Thanks
Zohar

[CitroJim]

the key transmits its factory programmed RF code to the CPH and from now on the CPH allows that key to lock/unlock the doors ?

I believe that is how it works Zohar.. The key has a chip in it and that's the bit that's programmed by the CPH...

I also believe the key transmits a different code on each use - a so-called 'rolling code'. The CPH knows in advance what the next code will be, in fact it knows in advance what the next 50 or so codes will be to guard against loss of synchronisation should the plip buttons be pressed well outside the range of the car receiver...