EFC250

Hi all,

New to the forum as i just purchased my first MB this week. A 2013 C250, Obsidian Black, AMG Pack, Vision Pack - only 25000KMs.
Anyway - I had the car checked and as you would expect it is basically in new condition. Although it was mentioned that there was a comms fault with the battery sensor - however, he said that everything was behaving correctly. He even said the stop/start was working fine as he had it engage on the test drive.
I picked up the car this week and noticed that the Eco light is yellow - now I know Eco is conditional - however, I have 45km drive to work one way which is a nice long highway drive. However, the Eco light still remains yellow.
Additionally, I cannot get the brake hold function to work. I have tried all the little tricks to no avail.
Doing some searching on this forum, it would seem that these issues can be battery related. Given the the car is 4 years old and only has 25000Kms on the clock, that is just over 5000kms a year so I am thinking the batteries could be due for replacement.
I want to try and use a CTEK trickle charger before I replace them.
However, I am unsure what the correct procedure for charging both batteries is. So I just hook it up to the main battery and the ECO battery will charge too or do I have to charge them separately?
Any help would be awesome as I can't seem to find the correct procedure for this.

mrbrannin1

i also have a 2013 C350 white amg sport package 71K miles... and my eco button is green all the time but never does the start stop for the 2 months that i had it..

CJG

It should work correctly. Sounds like neither of yours is. Not sure if the battery is the issue or not. I know it’s also dependent on your heat or A/C reaching the set-point, but after that long of a drive your car should be at temp.
However, I disable mine every time I start the car. It’s a horrible function. Just adds cycles to your starter and wear on timing chain, etc.

dlgkswh88

Just like CJG said that I think these functions dependent on the car's heat or A/C reaching the set-point.
I have brought the car in to the dealer for a service and mentioned about this issue and they said they fixed the wiring somewhere in the bottom.
Even after the fix, my car sometimes does not perform the HOLD function all the time.

I have the 2014 C300, and I think these issues appear to happen when it gets cold out.
To my experience, when I start the car for the first time in the morning when it's cold out the HOLD function would not work until I get to my destination no matter how hard I try in different ways of applying the brakes.
So what I did was I shut off the car when I reached my destination and turn it right back on and went around the parking a lot and try to use the HOLD function and it works.
It works as many times as I want after that.
So I think it is due to temperature related issue, but next time I bring the car in for service, I will mention again that the HOLD function does not work all the time since they claimed they fixed it under the warranty.
Also, I will let them know that this function is dependent on heat or A/C unit or could be battery related.
I think I read a thread where a member here replaced the car's battery and it works again flawlessly.

In the meantime while they were fixing my car, I had a W205 C300 loaner and the HOLD function on that car worked all the time regardless of any conditions.
So I guess they fixed the issue on W205 models.

As for the ECO function, I know it works conditionally but mine sometimes remains in yellow for a long time.
This also happens when it is cold outside.
I could be careless whether the ECO function works or not, because it is the first thing that I turn it off after I first start the car.

Let us know if you find other solutions to this.

dlgkswh88

So I searched online, and found out many people with Mercedes have this issue with HOLD function not working properly.
The solution was battery was replaced with higher capacity one (80Ah?) and the problem was solved.
I may replace the battery (not so soon though) as well to a higher capacity one and see if solves the issue.

xsever

Shouldn't the W204 have a 100Ah battery to start with?

dlgkswh88

I am looking at it now and the part number for stock battery for 2014 C300 is 000-982-32-08?
I think it says 85Ah, but not sure if I am looking at it right.
People say stick with OEM battery, but not sure if Mercedes carries higher capacity battery than the stock one.
I am not a battery expert at all, but do you have any recommendations for the battery?

LogicalApex

I have a 2014 C300, but owned a 2013 for a few months before a crash killed it and there isn't much difference between these two cars (which makes sense as they are both facelift W204s).

The HOLD function is slightly different than the ECO function. I have never really had any problems with this function, but it did take some getting used to when I first got the car to activate it reliably. You can't press the brake too hard when stopping if you want to activate this reliably. Reason being is that the HOLD function is activated after the car as come to a complete stop and then you press the brake a bit more. If you press it all the way down to the bottom to stop you won't have any room to activate it. Once you have the car at a complete stop press the peddle a bit more and you should have it activate reliably.

The ECO function has a few "checks" that it does when it decides whether or not it should activate. It can't be too cold outside (above 20F I think) or too hot (less than 90F or so). The cabin temperature has to be close to what you've set (Mercedes recommends 72F for it to activate the most easily). The car has to also satisfy other internal checks as well.

Some extra details: http://media.daimler.com/marsMediaSi...ml?oid=9361921

NZ-Merc

Hi,
I would defiantly recharge your battery with the Ctek as your first step, my 2016 A180 stop start was not working and once the battery had been charged with the Ctek overnight it now works every time once warmed up,