Please do not contact me saying they don't work because they do if you do it right.
So, if you drive more than 10,000 miles a year, you'll get the mileage/KM countdown.
If you do less miles over the year, you'll get a day countdown.
If you just see a number, the service is due in that amount of time/distance.
However, if there is a - before the number, your service is overdue.
However, there seems to be a confusion over which type is being shown.
Distance
If it's a mileage or kilometer countdown, it will be shown in increments of 100.
Also, when the number is shown there is a miles or KM logo next to it. (bit of a give away).

Days
If it's a day countdown it will be shown in increments of 1 with no logo next to it.

In some instances, people have found that double tapping the button doesn't bring up the spanner icon(s).
If yours is one of the rare few that doesn't, try 3 or even 4 presses to see if the spanner icon(s) appear.
Stop right there, the video states
"works on all smarts, button placement varies between models". (except 453).
So if it's a smart it will work. I really don't need to make a video for
each model do I? When the only difference is the position of 1 button!
Yes it does.
A few times a year I'll get an email stating that they tried to reset their service indicator a hundred
times and it didn't work ....but.... when they did something slightly different, it worked 1st time.
I tried loads of times but it didn't work but when I:
"Started the car's engine instead of just switching to position 1, it worked"
"Walked clockwise around the car 3 times first, it worked"
"Prayed the sun God Ra as I held down the button, it worked"
Seriously though, don't email me with your variations. Your car isn't unique. This method works.
Right, that's a more sensible question.
450 Fortwo

451 Fortwo

452 Roadster

454 Forfour

Every now and then I get someone tell me some new bit of info about reseting the service light.
Just because they believed what they heard or they tried something different during
or before resetting the counter, they now believe that is the correct way to do it.
Proved wrong
Myth 2 - You can reset a "1 spanner" service but not "2 spanners". You'll need MB Star for that.
Proved wrong
Myth 3 - The car has to be in reverse to reset the service counter.
Proved wrong
You can only reset the service indicator after doing 2000 miles from the last reset.
Not sure on this one, why would you want to?
Yes, it still works, even on the electric drive ED 451. Thanks to Darren W for the confirmation.
merchants
450
Blue - 0001270V004C05A00
Silver - 0001270V004C48A00
451
Not available separately
Roadster
No longer available separately
Part number used to be 0014897V002000000
454
Not available separately
Credits
Jacqui J for the "days countdown" photo
Ben C for the "miles countdown" photo
451
Not available separately
Roadster
No longer available separately
Part number used to be 0014897V002000000
454
Not available separately
Jacqui J for the "days countdown" photo
Ben C for the "miles countdown" photo