Right, so, I bought my 2015 Mercedes e220 AMG line Cabriolet at the end of June, it has 51,000 miles on it. I noticed after driving it for a week that the start stop wasn’t working properly. The ECO on the drivers display was amber and only went green 2 times in that week of driving. The first time it went green and stopped at the lights the engine shut down as it should and then immediately started up again and went amber. The second time it went green it worked normally but when it eventually went amber again it didn’t come back on. I’m not getting any warning messages for the battery and I’m not getting any for the Auxiliary battery in the boot either.

Took it to Halfords for a free battery check and they told me it needed replacing. Bought a battery charger and put it on charge till it was fully charged up and ran it for a day without the radio, heaters etc on. ECO went green almost immediately and continued to work for a while that day. When I got home I checked it again and the battery was at 50% 12.7 volts. I turned the engine on and saw that the alternator was returning 14.8v. Took it back to where I bought it from, they tested the battery themselves and said there was nothing wrong with it. They tested it and showed me that the battery charge was at 50% and recharged it for a few hours as they said it needs to be at least at 85% for the ECO stop Start to work. When I came back a few hours later they said it was working fine, which it was but after normal DRIVING usage (not sitting in a garage) the time in between the ECO light being orange and green got greater till the point where I’m back where I started and it doesn’t come on anymore. THERE IS NEVER ANY ERROR MESSAGES. Took it back again to where I got it from and they sent it to a German car specialist (after charging it up) and they said there was nothing wrong with it.

I’ve recharged it again since and took a 6 mile round trip to the shops and tested again and it’s at 50% again. I tested the Aux battery and it was almost fully charged, put the charger on and it was fully charged in five minutes and voltage seems fine on that too.

I have a months warranty on it, I could replace the battery’s myself but they won’t give me the money back as it’s showing fine on their tests.

I know the car has to meet certain parameters for the eco start stop to work, if they weren’t getting met then it wouldn’t go green almost instantly after a full charge. Personally I think it’s the main battery.

Although I am taking it back to them for further tests it’s an hours drive away and at the moment there isn’t a courtesy car so I’d have to wait for hours. Car works fine and I know you’ll probably think I’m crazy for wanting it to work but I’ve just spent over 15k on this car and just want it to work 100%.

I’ve got a battery tester arriving today.

Anyone else had this or any ideas?

Thanks

 

The battery is the problem. Unless the battery is in tip top form then stop start will not work. Of course the dealer does not want to pay out for a new battery - as evidenced by the fact that they charged the battery and sent it to the German car specialist (nothing special because it is an MB, Jaguars have the same problem if the battery is not in tip top form) otherwise they would have sent it without charging the battery.

The car is not performing as it should so tell the dealer to sort out the stop start issue otherwise give you your money back.

Sounds like a dealer to avoid.

A Jaguar XF that I had sop start function started again once I had replaced the batteries. My A207 now only stop starts after I have used the car for a long run.....because the batteries are now a little tired and need replacing. You can understand why the stop start stops working when the batteries are old and no longer at full efficiency as there could be a danger of the car not restarting. By the way my car is a 2015 on original batteries.

 

To be fair, they’re not a bad dealer. They’ve been very good all things considered. They’ve now ordered me a new original Mercedes’ battery and it goes in on Monday to have it replaced. I just hope this is the problem. Thanks for your reply it’s greatly appreciated.

 

Hopefully, they will attach a slave battery during the change. Modern cars can have problems with the software in the various units if power to them ceases for a short period.

 

New battery fitted today by dealership, things seem to be working fine now but I’ll let you know in the next week or so. ECO light goes green almost straight away now.

Thanks for all you help

 

hi Mark,
I would like to know if you have solved this problem? Did you replace the battery under the hood or the auxiliary battery?

 

hi, yes I replaced the the main battery under the hood. Stop start works fine now and I’m having no problems at all.