Originally Posted by
Viper-666
The kefobs from a MB SLK R170 after facelift are identical with them from the Crossfire. So technical it works with the Crossfire, but it has to be programmed or the right chip has to be replaced.

OP post 4 (
I used the internals of an old Mercedes key but.... ).
Doesn't say a 171, doesn't say where he got it from. NO guessing if it has the same internals since he will be getting a used crossfire circuit board... If and when he gets a used CROSSFIRE FOB and swaps the circuit board (and the circuit board isn't damaged 'tested with batteries and the LED lights up'), he WILL have a FOB that does the lock/unlock. I don't have an one to send him and there is no reason to replace the SKREEM or buy a new key! IF after he gets a working used FOB and installs HIS 'little chip in the head of the FOB' (that allows the handshake for starting), he will have invested some time and whatever the USED crossfire FOB price was.
A HELLUVA lot cheaper than any bypass, soldering of a chip, or new replacement key. There is enough misinformation even with this thread so I am now out of it. Good luck OP!
.