ArthurJ

I purchased my S550W4 new January 2015, by late spring and about 1800 miles the eco-start operated for the first time and perhaps 5 more times. 2016 it worked about 15 times starting late June and stopping early September. I have a 2015 ML250, 2017 C300 and 2013 SL550. The eco-start feature works year round on all of these vehicles as long as the ambient air temperature is above 40-45 degrees F. The dealer insists there's nothing wrong and there are many parameters to be met for this function to operate. I was told the S550 is so complicated, it's less likely to operate. And as long there is no error message, nothing is wrong. I appreciate that so many wish to permanently disable this feature, whereas I am of the old school. If MB says I need the feature, I need it and I expect it to work. I don't know anyone locally who has this vehicle so I have no basis of comparison. MB customer service says take it in and have them run a diagnostic-which is now scheduled. Does anyone have experience with this?

flint350

It used to work fine on my 2015 S550, but in the last several months it simply doesn't engage. I can turn it off and on and the E light shows up in the dash. It just doesn't work anymore. Maybe it's related to how charged the battery is bcz I take a lot of short trips which don't charge the battery much.

ItalianJoe1

The eco system is there to save fuel for emissions reasons. The car has the a/c off for EPA testing, which will make the eco start engage all the time. This is one way they can optimize the feature to help get better mileage during testing, as most people will never shut the a/c off (being that now you have to go into the menu via Comand, there isn't a button). With the a/c on and the other electrical loads normally present in a 222, there's not a lot of chance for the eco mode to turn the engine off.

In reality, the alternator is barely capable of sustaining the systems if you are using everything at a low idle rpm, so to shut the engine down there has to be a good surplus of energy built up in the battery. If you were running at a nice crusing speed on the highway and it had built up a comfortable cushion and you came to an exit and stopped, with the a/c on low and not every electrical consumer running, it will probably shut off for 20 seconds. Turn your a/c off and it will shut down all the time.

Nice Ride

For sure depends on multiple items, major one being AMPS in battery followed by temperature of engine. In winter, I barely drive the car. When I do, even with parkway driving, it takes about 15 to 20 Min. for the ECO to turn green...

RSouthern

ArthurJ,

One more thing to try. After the engine is at running temp (190-200 on the temp indicator on the lower right side of the instrumentation), when you bring the car to a stop, hard press or double press the brake pedal so the car is in brake hold (Hold is displayed on the instrument cluster). you should be able to take your foot off the brake pedal and the car is still stationary. Then if the eco-stop hasn't kicked in, bump the gear selector up so the transmission is in N (neutral). This combination triggers eco-stop most of the time on my 2015 S550W4, even with the A/C on.

I find that on my car it feels like the transmission sometimes isn't fully disengaged at a stop and I can feel a slight vibration when it's in drive (D2) with the brake held. Bumping the gear selector to N fully disengages the drag from the transmission so the engine runs completely smoothly and the eco start seems more likely to trigger.

hyperion667

S/S in worthless IMO, and a trick to make us think we're getting better fuel economy.....be thankful it doesn't come one and off. First thing I do in my car is turn it off by pressing the S button anyway