Problem with starting E350?
I have a Mercedes E350 2011 4 matic.
Most of the time, my car starts normally, however, occasionally, we need to boost it with another car battery. It's very sporadically happening, and enough for me to think there's a problem.
We have checked the battery and it appears to be working well. And also, when I exit my car, I make sure everything is off. I was on vacation for two weeks and came to start the car, and there was no problem starting the car.
Therefore, I thought that if it had been sitting there for so long and was able to start, it couldn't have been a battery problem. But then, two days later, we had to boost it. I'm thinking it might be something electronic maybe. I still feel there is something electronic that is running the battery occasionally in the background, and I don't know.
Any help or suggestions?
Last edited by PeterUbers; Nov 27, 2014 at 11:58 PM.






I have a Mercedes E350 2011 4 matic.
Most of the time, my car starts normally, however, occasionally, we need to boost it with another car battery. It's very sporadically happening, and enough for me to think there's a problem.
We have checked the battery and it appears to be working well. And also, when I exit my car, I make sure everything is off. I was on vacation for two weeks and came to start the car, and there was no problem starting the car.
Therefore, I thought that if it had been sitting there for so long and was able to start, it couldn't have been a battery problem. But then, two days later, we had to boost it. I'm thinking it might be something electronic maybe. I still feel there is something electronic that is running the battery occasionally in the background, and I don't know.
Any help or suggestions?
You need to check to see if you have two batteries before you do anything.
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For 2014+ W212, there are 3 batteries: 1) Main battery, 2) Auxiliary (transmission) battery, 3) ECO Start/Stop battery which powers the electronics when the engine's off.
For 2014+ W212, there are 3 batteries: 1) Main battery, 2) Auxiliary (transmission) battery, 3) ECO Start/Stop battery which powers the electronics when the engine's off.

I only knew about two batteries (under hood: I believe for starting and with posts for jump-starting, in trunk: I thought for ECO to power accessories when engine is off). Where is the third battery? Anyone know the precise function of each, in case I was mistaken?
Last edited by konigstiger; Jan 17, 2015 at 04:00 PM.







