al300sd

I have been around a few cars with start stop technology they seem to shut down almost always when the car stops. my 14 e550 almost never shuts down at stop. I initially attributed this to short distance mixed driving (15min 6 miles). However i recently came back from a 3hr 120 mile trip mostly highway and some back roads and eco did not engage. I had the ac off music not blasting daytime driving. Also as a side note when the eco mode did turn on it would only keep the car off for maybe 1minute before disengaging. Should i change the aux battery? The service history indicates that it has never been replaced.

KEY08

Yeah, mine slowly died as well in the past month or so. It's definitely the battery and there is no warning for it. I'm in no hurry to get it in to the shop though because I hate the feature. 2014 here too and on the original battery. E550.

al300sd

Maybe i'll wait until spring and replace both. My luck i will have to do it in a blizzard. im looking into AGM batteries as replacement

KEY08

Are you still under the original warranty? I am and just hoping to get them to give me a free battery back there.

al300sd

I am not, but i saw that alot of service histories while shopping for the car and the Aux batteries were changed out after 2-3 years. I would imagine this was under warranty.

kajtek1

I know ECO mode needs like 7 parameters to meet before it will engage, but in city driving I had it shutting down after 1 mile, where it would not shut down after 10 miles drive. At some point I noticed dirty contact on trunk battery and cleaning it seem to make ECO coming more regularly, but still not sure how much that was placebo effect.
I wish we would have program that would display the 7 parameters during drive. We have about 10 stop lights on 6-lanes street before we reach freeway so having predictable car mood would be nice.

LALALAND

This is what I found out about the number of times it will be activated per manual. It might be what you mean 1 minutes.
All vehicles (apart from AMG vehicles): automatic engine switch-off can take place a maximum of four times consecutively (initial stop then repeated three times).

I did start another thread asking if the aux battery can be charged as I didn't want to hijack your. Maybe the answer might help both of us if it could be done to test it out if it help. Per youtube video, changing the aux battery seem easy even none shade tree mechanic like me.

dbldpr

since you live in Chicago go to Midcity Engineering near the north side of Chicago and have them install a eco module and you no longer have the feature. only cost a couple of hundred with the installation. Takes about 1 -2 hrs.

al300sd

Just an update pepboys is offering Bosch AGM batteries at a discount on black Friday.

KEY08

Took my car in for an A service and they confirmed my ECO battery died. They replaced it for free (yay) and now my start/stop is functioning properly.
So, now I have to remember to turn it off....

baba_metca

Hello there, my father has a 2015 W212 E350d 4matic model. Couple of months ago there was a message that the AUX battery has failed and some systems stopped working including start/stop function. After a visit to the dealer and a new AUX battery everything was normal except the Start/Stop function. Before that message the start/stop function was working. Now he called the dealer and they have explained to him that several parameters have to be in sertain conditions so that the system could light up the green icon on the instrument cluster /as now is yellow all the time/ . Yesterday was a good day and I went for a drive. First the climate unit was off all the time, then I made a 6km to the highway, then a 25km on the highway, then another 25km back to town on an extra-urban road. And still a yellow light. No lights, no music, no heating seats. Outside temperature was 7 to 8 C . Also the average consumption for this trip was 7.3 l/100km.

Do you have any suggestions on what could be the problem or what to check. The closest MB Dealer is around 40km away and if we can check some stuff before going there will be good.

KEY08

baba_metca

The AUX batery is in the trunk. It had a message on the instrument cluster and the Distronic Plus was not working too. Then they have changed the battery /the one in the trunk/ and the Distronic Plus start working again, and the Start/Stop started to light up(as it did not light up before the battery change). But after a while my father recognised that the Start/Stop is not engaging /only orange collor on the instrument cluster/. On the invoice there is this number A09829308 /Additional batery for Eco Star-Stop function change/.There was a 541137 line too /alternator voltage regulator short check/.
Now we are suspecting the main battery, as the car is 4 years old, and for the first two years the car was a showroom test drive car /no one knows what were the driving cycles then/. But we do not know what should be the voltage of the battery after a cold start, after a run /when it heats up/ or what to expect from the alternator too. The car 'sleeps' in a garage, and the temperature in the winter is always above 0C, at the moment is around 10/outside 0-8C/. Last winter was colder and the Star/Stop was working in temps below 0C no problems.

baba_metca

Aslo what should be the voltage for the trunk battery, it could be defected for all we know.
Can someone tell what will happen if we remove/disconect/ the trunk battery for one or two short trips, and then reconect it again. Will it require a software interference after reconecting?

KEY08

Check the state of charge of both batteries then with a multi meter. They should be at 12.7v to be at 100%. Print out a Voltage chart to compare where your batteries are at. 12.2v reflects a battery at only 60%. 11.9v is a battery at 40%, etc.
Good luck.

kajtek1

Checking only battery voltage will not tell you much. It will tell you if the battery is dead, not nothing about its actual condition.
I had load tester for years, but even that is good, it still is not 100% reliable, so lately add new technology - Solar tester to my toys collection

KEY08

that looks awesome.

kajtek1

And it seem to work, even I have no idea how it does it.
I have several batteries and one from the boat, even it seems to be never installed, did show 340 CA on 750 rated battery.
I used the battery for electric pool pump and in the mean time run it couple of times via desulfating mode on my charger. Now it shows 540 CA. Still not passing, but better.
That battery passed load test.

baba_metca

Thank you. I will write when we have some results. I think that we could try a battery swap for testing with our local battery shop.

KEY08

Yes, that is also an option to put in batteries that you know are fully charged and good to see if they make a difference.

kajtek1

Swapping is always an option, but I read too many times where members come with electrical problems, where they put new battery and 40 replies later they decided to replace new battery as it turn defective.
I've been dealing with lot of batteries for my toys and before the gizmo I linked above, the load testers were the best, although still not telling you actual CA number.
I am trying to research how the new Solar tester works, but it is using some kind of high-frequency modes.
Sounds very strange to me, that is why it took me 2 years to finally buy it, but it works and can't beat that.

baba_metca

We are just trying to get as much info at the matter as possible and check whatever we can to be sure, before visiting the dealer. Unfortunattly all the local battery shops have an outdoor service aria and the weather here is bad until the middle of next week. It rains and in a few days will have a wet snow. So we will delay the ckecks for next week. Any other suggestunes are welcome. Thank you all for the responces and I will keep you informed of the results.