Eco stop/start won't work correctly
 

I have a c class 220 diesel bluetec. My eco stop/start is most unreliable all through winter not a chance of it working and only now will it work if I run for five minutes, temp of engine well up, all heating not high so everything is for go. Still get orange light no stop/start working. When I stop at traffic lights I manually turn off the engine take out the key reinsert it and then wait for the lights to change, then I start the car and set off in the normal way. It is only then I get a green eco light, it is now working for the remainder of that trip next time out the same thing happens. It will not do it automatically, and sometimes when I do it, I get a green eco light for a blink of an eye and then it reverts to an orange display. Twelve months ago, it was doing the same thing and my MB dealership said I had a faulty relay with I assume they changed it worked for some time and then failed last winter. The car has only done 6,000 miles so far. And the Eco has been not working for at least half that mileage.

I would have the dealer look at it again. I would see if the capacitor is going bad.