Does the "Hold" SBC function work on US spec W211's?
 

I've tried it and can't seem to make it happen, and think I remember hearing it's only a Euro feature, but doesn't hurt to ask ;)

No, and I have spent some time in SDS looking for an option to enable it, and have been unsuccessful so far. I haven't looked in a while though.

I think the SBC hydraulic unit is different , not only software need to be updated but also the hardware

Almost but no cigar!
https://mbworld.org/forums/e-class-w211/238997-brake-hold-function.html

So the 07+ have them? Hmm, I wonder if it has to do with not having the SBC unit, but the E63 still has SBC.

SBC Hold and Stop
 

Here in South Africa the SBC hold function was only introduced during 2004 (thus models from 2002 and 2004 did not boast this feature) and when the SBC pump was dropped with the face lift in 2007, an equivalent hold system was introduced.

Are you triggering the Hold function correctly (it takes some getting used to, but thereafter very easy to apply)? You need to swiftly depress the brake pedal even more after your car has come to a halt.

However the SBC based system has one advantage to the newer face lift system it boasted SBC stop (activated at low speed by pulling the speedtronic lever toward yourself) and is very convenient in bumper to bumper traffic. if you release the gas pedal the car will automaticaly decelerate and stop and hold the car by applying brakes.

The latter was discontinued for the face lift models...

It was never an option (therefore not listed in any manuals) on the US versions of the W211. We got left out for some reason (legal reasons I am sure)

SBC-stop was deleted from the 2005 model year, model year code 805 on European cars. I have a 2005 car, it does not have SBC-stop, only SBC-hold.

my 03 e55 has SBC Hold and SBC Stop.

Do you mean you come to a stop at a incline and release the foot from your break pedal and your car won't roll back??? If so, it works just fine on my car and it is a US W211. It doesn't work in S only in C. I hope I understood your "Hold" correctly and didn't spam in your post!

Actually I'm gonna try that "Hold" thing, sounds cool. I was referring to the non-incline one but thanks for the info!!

I bet that it only works on certain inclines. You already mentioned it doesn't work with S. S starts of in 1st whereas C starts of in 2nd. The torque differential might just be enough to hold you in place.
This functionality is intended to work even on level surfaces. Therefore the incline bit is a matter of torque in this case. Get to a real steep one and it probably will work in S mode as well.

The SBC hold or "Hold" in face lifted models actually does eactly what it states (it lights up in the centre console). It holds the vehicle to it's position by applying the brakes. It does not needs S or C setting on the gearbox. Since it uses the car's breaks (you no longer have to keep your foot on the break at a traffic light and automatically disengages when you hit the gas pedal) there is no issue whether you are facing down hill or uphill or if the vehicle is level. It is one of the nicest features of the W211 series (where available) in my opinion.

Those that want to use the in drive mode (counter torque from the engine) to virtually "hold" the car against a particular suitable incline should be aware that this may heat the tranny unnecessary as torque needs to be continuesly applied to the drive wheel in order to avoid the car from moving backwards. I would guess that this is not a preferred driving style for longevity.

Did it work?