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[lil.smartie]

A 2nd hand key fob can be coded to a forfour with STAR. We've done it twice, they were forfour ones though not colt ones although there is no visible differences between the two.

Kate

[djames108]

Is there a particular method of doing it as it just refuses to start the coding process it just says unable to continue.

Ive even started the coding with my original key then swapped over at the next stage but the codig fails

Ive even bought a new transponder chip and fitted it to the fob but it says the same

The keys (smart and colt) are identical they have the same chips and boards etc.

[FireFlower]

So the current plan is to buy blank key with electronics also, get it carved in other shop and reprogrammed by Mercedes reseller for 50€.

Total cost should be under 100€ then right?

Can someone link me a complete blank key or just the key part with casing and electronic separately.

[djames108]

best way would be to get a 2nd hand key as cheaply as possible (ebay)
Then again ebay they do the blank cases with blade attached which you can go get cut at a good key cutters......this is of course IF you can recode a 2nd hand key to another car, I've had no success yet just waiting for lil.smartie to confirm how it was done?

[lil.smartie]

Same way as a new one from MB with STAR.

Kate

[djames108]

Ive tried with STAR but as previously mentioned it refuses to code the key saying its already coded to another sam unit?

Apparently the transponder chip (PCF7941) can only be written once and coded to a sam from new.

[lil.smartie]

We've done it twice, once on the car that's now at s2 (belonged to Paul's ex-wife previously) and another as a spare to Pauls Brabus. Don't know what you did wrong, maybe your kit can't do it, proper Star can!

[FireFlower]

Asked again from Mercedes dealer and here is the answer I got him. I asked can you order key electronics separately but it is not possible (for them).

Hello, the key will be ordered from Germany by manufacture ID and is coded ready for your car there. There is not any replacement parts for they key except the battery a4547600106. The Key costs 222.00€

Well have to order it. Better than losing the last key and changing whole lock system.

[Alex]

Just take the RF transponder and put it in a safe place, like your wallet. Then cut a simple key to duplicate the existing one, and voila. Two keys that work when you're in the car:P

If you do lose the chip and one of the keys, you still have the other to unlock the car, un-jam the steering, switch on lights etc, so you can safely get your car back home and order the unjustifiably expensive key from merc.

[lil.smartie]

If you lose both keys (ie no coded part, a blade is not enough!!) you need a new front SAM unit as you do not have a key programmed to the car as a master to add any others.

This is also true of a 451 fortwo.

Kate

[djames108]

Have just obtained a used forfour key to try as I thought my issues were down to the coding process mitsubishi use. Same problem with the forfour key

I think as mentioned above the issue lies with the working key I have, it is showing as a spare key and not a master key. I assume now that I would need the master key in order to code another key, perhaps even if i bought a new virgin key?


Come to think of it, if you ever had to change the ecu for any (other) reason, surely you wouldn't then need a new key set as well?
Therefore could you either replace the ecu (Or reprogram the existing one as if it were new) then code the key to it, which would then make it a master key?

The next question is.......can the spare key be changed to a master key? Or would the only option be a new sam and key combo ?

[FireFlower]

Well Finnish Merc dealer said that they are not actually doing the coding for the new key. They need my car's ID number, they send it to Mercedez-Benz to Germany, They look Car's ID from database, program key there and drill / cut the key, then ships it to Finland and you have a new key. Then at local Merc Dealer you reprogram the keys to new, so the lost key cannot be anymore used.

Well I got that kind answer... And I don't have any idea is my key spare or master... Well going to buy new key for 250-300€ from "Veho" and ask about which type my key is.

[CrazyG]

Perhaps Kate (aka lill.smartie) can give us an insight into
how this whole key programming/replacement thing works...? ? ?
If not, I'll ask Rob.... as n when I see him sometime (if he knows)
of the actual technicalities behind the whole thing.

[djames108]

I have tried to cheat, once it accepts the working key i have for programming i swapped the chip over but the coding failed and threw my existing key out so i had no working keys.

It did let me code the original key back in though but as a spare again and not a master.

[Brabs]

Hmm, I didn't realise a that there is a 'Master' key and a spare key! I thought that they are both the same. Mine certainly look the same and I've therefore no idea which is which!!