W204 ECO mode

[Wigglemethis]

Hi All

I have a little puzzle for you sorry it goes on a bit...

So I have a W204 2012 AMG Sport Plus just out of warranty....

Over Christmas the stop start didn't activate for some weeks. Eventually I got round to having a look at it so i though id park it in my workshop have a plug in and take a look. As expected no faults found and nothing obvious.

So I pop out for lunch the same day and all of a sudden its starts working for the rest of that day.... Next morning and days nothing.

I replicate what I did previously and just parked it in the workshop while I hoovered it out same again worked for a while.

A few days later not working again and me suspecting its something to do with the temperature I park it in the workshop all afternoon low and behold the eco starts up again this time for a few days. then gone again.

Now after trawling the internet with not much said about this tec I suspect the Intelligent battery sensor but at £140 i'm wondering if anyone has had this and can confirm my thoughts or lead me in another temperature related direction.

Cheers

Graham

 

[television]

Many give upon this feature and have the same problems as you, I have no idea on it at all.

 

[Wigglemethis]

Eco

Im not really concerned about the feature but I hate not figuring it out I like things as they should be.

I don't want to pay some merc tech silly money out of principal as I am and engineer myself. and from what i read it wont actually show a fault on mercs system as it just thinks the battery is cold or whatever and will be trial and error.

Im wondering if there are more temp sensors that control this as the fuel consumption seems to be affected (I accept this could be just in my mind)

 

[ioweddie]

I think its outside temperature related, my W205 used to stop start all the time in the summer, but now its occasionally once its warmed up and on longer journeys only.
Only a guess though

 

[Wigglemethis]

The outside temp seems accurate I'm leaning to the battery sensor


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[geraldrobins]

I often find when mine doesn't work as it has before, then a quick on off of the ignition and engine cures it while waiting at traffic lights etc.

 

[Wigglemethis]

Its definitely temp related as several times I have warmed the car and it works again


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[John Laidlaw]

Definetely temperature related- the last 2 I have had don't operate below about 7oC- hence why they operate fully in Summer really

 

[C350Carl]

Seems odd, my S212 has been working fine and it's been below 7deg here the past few days.

Even today after driving 12miles and it was 4deg (according to the dash) the Eco symbol turned green on the dash after about 10miles. It was 10miles through a 50mph average speed on the A1M though so that may have helped.

Worked fine the final 2 miles which was through 3 sets of traffic lights.

It did take a while to fire up when the temp was only 1deg on Tues though. Think it was about 20miles on the A1M before it turned green. Worked fine after that though.

 

[Wigglemethis]

I'm talking not working at 10 deg


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[malcolm E53 AMG]

Interesting post.

My 212 e350cdi (12 reg) ECO stop/start function has so many parameters to meet ie, battery condition/charge, engine temp, cabin temp, cabin condensation, consumables in operation etc it's unlikely to operate unless the car is used for a long run at this time of year.

Personally I can't say I'm that bothered by this as I find the facility hopeless in slow moving tailbacks to a lot of roundabouts and junctions locally but I can understand the OP's frustration if it's not working properly.

One of my main concerns with the stop/start system is the extra load/strain on the battery and engine components especially timing chain/gears and auxiliary belt etc consequently it's turned off more than on

 

[EmilysDad]

stop/start would drive me insane. I've driven one car with it ..... a courtesy B Class and was a passenger in a SLK the other day from dropping my car off again again that had it .... even as a passenger it was getting on my t1ts.

 

[tode]

Its definitely temp related as several times I have warmed the car and it works again


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The only way to get to the bottom of it is to work through all the parameters that affect the ECO and eliminate them one by one.

 

[turbopete]

i believe outside temp when the vehicle is started is 1 of the parameters used for the eco system, hence it works 'better' when the car is kept warm in the garage and not so well when parked outside

 

[Roxie]

The interior humidity sensor would be my guess.

This problem is very easy to find out why it does not work on a Star diagnosis there is a menu that tells you exactly why all that is needed then is some checks to isolate the cause.

For instance if the problem is a risk of fogging then check the AC control which could indicate unexplainable values for the humidity level. If the cause is on board electrics then check the additional battery and the battery sensor.

 

[Wigglemethis]

Thanks for the replies. If it was the humidity sensor interior why would it not start working when the interior got warm after a run with the heating on thus drying the sensor out?


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[umblecumbuz]

My brother has stop/start and dislikes it. In slow moving tailbacks, there is a delay each time he creeps forward, while everything re-engages.

He pictures the day when all vehicles have this feature, which will create an accumulating delay on every tailback as each car holds up the one behind for an additional second or two! What fun! And that is not counting the cost in wear and tear on engines and components.

 

[C350Carl]

Just to show it does work at low outside temps.

Apologies for the crap photo. The wife took whilst I was driving.

This was taken 7miles into the journey and I had only been on the M'Way for 3 miles of that sat at 50mph.

 

[John Laidlaw]

Carl it was already telling you to stop for a rest after 7 miles! What were you doing ??

 

[C350Carl]

Carl it was already telling you to stop for a rest after 7 miles! What were you doing ??

Ha ha.

I'm hoping it isn't as the symbol is always on unless I switch the attention assist off!