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[bernatgabor]

Hello, so I've lost my only key a few weeks back for my Smart Forfour. Yesterday the replacement key finally arrived. So the car went into service today for programming them (Mercedes Brentford - 243 pounds cost). They called me that they could not do the programming; as my front SAM unit couldn't be encoded, so they will need first to replace it (388 pounds cost). I cannot comprehend how this can be, all electronics worked as advertised before I lost the key. The represent said maybe water went into it; which I find hard to believe (the car has been at them for almost the last two weeks). I did take off the battery, I hope they did put it back before trying to encode it.

Anyone has any ideas what could be, or experience with similar cases?

Thanks,

[CrazyG]

Eh   
If it all worked before you lost the key then by rights there should
not be any problem coding the keys to the car...but not having heard
of anyone with a similar problem over the years I cannot say
categorically that the problem is with who is doing it.
I would have thought that MB in germany would have advised the
dealer that a new control unit is required if both keys needed
replacing.
I have sent you a PM that may/may not be of help. 

[bernatgabor]

They have been quite unprofessional so dunno, they changed up three times what needs to be done in such cases, and the thing has been dragging out for almost two weeks now.

The service manager said something around the lines that maybe water got into it, and it's not working, rather than only a new SAM unit can be encoded for the brand new key (when you don't have neither of the originals). That being said because only MB can encode the key, I don't have much other option than go ahead with the new SAM unit I suppose.

PS. Hmm I do not say your PM.

[Problemchild]

Water ingress into the ECU is not a problem and it's not even called a SAM - they are just talking about their experiences with a roadster.

I've never heard of what you are saying

Don't let them replace anything

It was working before you lost the key

Prob be quicker to hunt the key out haha

Lesson - even though it's £200, always make sure you have a spare key around

JJ

[bernatgabor]

I don't have the key though, and I cannot hunt it. I also towed the car there which was also not too cheap. And only they can encode the key, so I don't see much option here in my current situation then them to fix the SAM so they can encode the key. And they did not talked about the ECU but the SAM unit.

Yeah is good to have a spare key, but it's not an option for me now.

[Deszus]

It looks like they're trying rip you off nicely. Don't let them.

When having just 1 key. Is it possible to cut 2nd key and open key later mechanically/manually?
Or it must be cutted and programmed?

[bernatgabor]

So I've talked again with them, this time with someone more technical. The service manager was in wrong, the SAM unit is okay; but will not accept new keys. Google-ing around this happens ever so often, when you loose all keys, the SAM module may not accept new keys, and the only viable solution is to replace it. They use the old key when they're programming the new one, if you still have it.

Also the info about losing the keys is correct. If all keys are lost/stolen to your vehicle you will be replacing the SAM unit as well as purchasing two new keys. Not a cheap repair.

In order to program a key we have to get a code from your car (actually the code can be gotten from any smart they just like us to use your vehicle).
Then this code is sent to DTAC in Bloomfield Hills, Bloomfield uses the code sent to them to get a series of codes from Germany, usually 3 to 6 codes. These codes are entered into your vehicle to program the keys to your car. One code is used per attempt to program. If there is a problem the code is not able to be used again and you have to use the next code.
These codes that are given to the dealer are only valid for 5 days as well. This is why most dealers will not request the codes from DTAC until they have your vehicle there.

The SAM must see a valid key id to match what is programmed in the key memory. To do that the ignition switch powers up the electrical system and the key transponder is interrogated by way of the antenna ring in the ignition switch. If there is a match the SAM will actuate its internal start relay to operate the starter. This assumes the proper keys and proper programming.

[CrazyG]

So thy admit that the SAM should accept a new set of codes eh...
but they also admit that sometimes they don't, which indicates
that there is an issue with faulty SAM's, and that your car has one
of them fitted.
As it is a known fault to MB, then they should take responsibility
for the unit not being up to specification, and in my book they
should replace it 'ars gratia'.
After all, why should you have to pay out to replace what is in
effect a faulty unit that the MB factory fitted originally ?
I'd use that as a 'negotiating' point and offer to pay for the labour
cost of fitting the SAM, but not the cost of it...or offer to pay for
the SAM but not the labour cost of  fitting it.
One or the other....but not both.

[bernatgabor]

So they've installed the new unit, and still can't program the new key, "the engineer has been trying to find the issue for hours, seems some software trouble". He'll continue tomorrow. Fun times 

[Deszus]

New ECU is knocking to your door.

[Alex]

Should not rule out a weak battery. I've had weird errors when a battery was almost dead but the car would still start.

[Deszus]

Might be. It's dead easy to do battery check with multimeter.

[bernatgabor]

Surely the official service engineer thought of that during that few hours of debugging with all the fancy official tools available around. Otherwise the battery was in stellar condition when I towed in; granted that was 2 weeks ago.

[bernatgabor]

Just to finish up on this, the next day the programming worked on first try; and afterwards no other problems were detected, so that finished this.

[Problemchild]

User error

Makes me think they did it wrong initially too and maybe it didn’t need an ECU?

JJ