ECO start/stop function stopped working

[robwells]

The start /stop function stopped working in my 2012 c220 estate a few weeks ago. It's a second car and sometimes doesn't move for weeks at a time. I went for a five hour drive at the weekend, mostly dual carriageway and bit of motorway but the function still didn't work. When I got home the front battery showed 12.45v and the rear battery showed 13.30v. The ECO switch shows green but the ECO sign on the speedo shows in yellow. Any ideas of what the problem might be would be most appreciated.

[DastardlyDick]

Interesting - I did hear somewhere that the symbol goes yellow when a DPF regen is taking place. Your 5 hour journey possibly caused that which, from the DPF point of view, is a good thing. I haven't noticed it on my car but then again I tend to turn the eco button off always as the stop/start stuff just annoys me!

[Scrump]

Over the years I have had to replace both front and rear batteries on my E class. When the batteries were near end of life the stop start didn’t go green.
12.45v for the main battery after a long drive seems a bit low, maybe your main battery on the way out.

[robwells]

Many thanks for the replies. Looks like a main battery issue. Not inclined to replace it at this stage as I'm not that fussed whether the function works or not.
Regards Rob, from 'sunny' Southend-on-Sea.

[LeeM135i]

Our Mercedes sometimes sit for a few weeks between uses now we only go into the office when we have to. I have purchased a CTEK trickle charger which seems to have fixed the lost stop start and slow crank on start issues. I usually pop them on charge for a couple of days a month when (if) its dry to keep the batteries topped up and conditioned.

[Faszination76]

LeeM135i said:

Our Mercedes sometimes sit for a few weeks between uses now we only go into the office when we have to. I have purchased a CTEK trickle charger which seems to have fixed the lost stop start and slow crank on start issues. I usually pop them on charge for a couple of days a month when (if) its dry to keep the batteries topped up and conditioned.

THIS! - The battery on my new to me E63S is past its prime, I also bought a CTEK charger and it works a treat. However, I like the stop/start function working, so I'll be getting a new battery within the next few months...may as well keep the car 'as nature intended'.

[9000rpm]

if the AC is on and the car detects enough moisture in the air / on the screen, this will also disable start stop. to test this, it should just be a case of switching the AC off