Eco mode not working after first use

[AshleyME]

Hi,

So I have recently bought a W212 E class, however have encountered 2 issues Which I’m not sure are faults or just me not having the knowledge of the car.

firstly, once my Eco mode has gone from yellow to green and I use it once (start/stopping the engine) it automatically turns eco mode off and it can’t be turned on again unless I fully turn off the car.

Is this normal? Honestly have no idea.

secondly, when I turn the car on the middle screen inside the Speedo shows a picture of the car with the rear left seat illuminated, not sure what this is or what it means, but if I press ok it goes until I turn the car on again at some point.

Any advice would be greatly appreciated

 

[GeorgianSteve]

Hello,

1. Could be the ECO parameters are not being met. The car needs to warm up. Try turning the A/C off to see if that helps. How old is the battery? They have a limited life for atop/start.

2. This means it thinks there is a rear passenger without a seatbelt on. Do you have anything on the seat?

Thanks,

Jay

 

[AshleyME]

Hi,

just done a 25 mile journey to work with the AC off, used stop/start once at a traffic light and again eco went off for the rest of the journey.

the car is a 13 reg registered in June so around 7 years old, surely that battery wouldn’t be on the way out after that long?

with regards to 2. No there isn’t anything on the back seat

 

[Gazwould]

Bad for the timing chain , leave it off / disable etc .

 

[Farmer boy]

I recently replaced the 4 year old battery on my C Class as I had the same Eco problems. Even after a full day on the battery charger it would only work once the next day. All other electrical systems work perfectly. Having read about main or secondary battery faults causing the problem on the Forum I decided to replace the main battery. After the fitting of the new battery Eco goes green after about 100 yards and engine cuts and restarts as it should even during stop start City centre running. I understand that most MB cars have the traditional main battery and a small secondary battery or capacitor either the main or subsidiary battery failing can be one of the causes of the Stop Start Eco system failing. There are also other faults that prevent the Eco system working. I would give the car a 30 minute run or put it on a charger overnight then check the main battery voltage. In my case no amount of charging would get it above 12.3 volts. A good battery should be about 12.6 at rest.

 

[AshleyME]

I recently replaced the 4 year old battery on my C Class as I had the same Eco problems. Even after a full day on the battery charger it would only work once the next day. All other electrical systems work perfectly. Having read about main or secondary battery faults causing the problem on the Forum I decided to replace the main battery. After the fitting of the new battery Eco goes green after about 100 yards and engine cuts and restarts as it should even during stop start City centre running. I understand that most MB cars have the traditional main battery and a small secondary battery or capacitor either the main or subsidiary battery failing can be one of the causes of the Stop Start Eco system failing. There are also other faults that prevent the Eco system working. I would give the car a 30 minute run or put it on a charger overnight then check the main battery voltage. In my case no amount of charging would get it above 12.3 volts. A good battery should be about 12.6 at rest.

Hi,

thankyou for the detailed response, how much roughly would I be looking at to get the battery replaced?

 

[markjay]

I think you should be clear about what is actually happening.

If it the ECO symbol in the Instrument cluster remains yellow and never goes green, then the likely fault is ondeed with either battery (main or auxiliary).

But if the green light on the ECO button on the dash goes out completely, and the ECO symbol on the Instrument cluster disappears completely, then I would get the fault codes read with STAR before rushing into buying a new battery.

 

[WOODYTHEWISE]

As for the cost of a battery, give the dealer a call, may surprise you. At times they can be the cheaper option.

 

[ShaunB]

Hi,

thankyou for the detailed response, how much roughly would I be looking at to get the battery replaced?

Get yourself a CTEK MXS5.0 charger and charge the existing battery fully. The ctek unit will also tell you if the battery is good or bad aswell.
Cracking price on amazon at the minute too

 

[markjay]

The Stop/Start function on my 2013 car with the original MB batteries (both main and auxiliary) still works as it should.

The Stop/Start function stopped working around two years ago (green light on the ECO button on the dash went off), a scan showed a failed Brake Vacuum Sensor, this was replaced by Terry at WG (cheap and easy fix), and the Stop/Start started working again and gave me no grief since.

I usually turn-it off at the start of the journey, but whenever I turn it back on, the ECO symbol in the instrument cluster is mostly green, occasionally yellow, which is how it should be.

This also tells me that my original 7 years old battery is still in good shape

 

[Farmer boy]

Good evening Ashley

I purchased a Varta battery via the web and paid £160 delivered asI did it during the deep lockdown time and my local MB dealers parts department was closed. From memory mine is a 80 amp hour Stop Start AGM battery. Fitting is relatively simple and only takes about 20 minutes. Do a search on this Forum or Google.

 

[AshleyME]

I think you should be clear about what is actually happening.

If it the ECO symbol in the Instrument cluster remains yellow and never goes green, then the likely fault is ondeed with either battery (main or auxiliary).

But if the green light on the ECO button on the dash goes out completely, and the ECO symbol on the Instrument cluster disappears completely, then I would get the fault codes read with STAR before rushing into buying a new battery.

hi,

it's yellow when the engine temp is warming and goes green after around 5 mins, it’s once I come to a stop at lights when the word Eco is in the green box and the engine shuts off in neutral, once the engine stops and starts itself again the eco mode is turned off automatically and can’t be turned on again

 

[markjay]

In this case, I don't think the issue is the battery.

I suggest that you get the fault codes read by STAR.

It will be something else that's interfering with the Stop/Start function.

 

[AshleyME]

In this case, I don't think the issue is the battery.

I suggest that you get the fault codes read by STAR.

It will be something else that's interfering with the Stop/Start function.

this may sound stupid but what’s STAR?

 

[markjay]

It's the Mercedes Benz diagnostic computer. Dealers will have it, as will independent MB specialists.

 

[AshleyME]

It's the Mercedes Benz diagnostic computer. Dealers will have it, as will independent MB specialists.

do know roughly how much I’d be looking at for a repair?

 

[markjay]

It depends on what the fault is...

 

[wongl]

do know roughly how much I’d be looking at for a repair?

Hi AshleyME, your profile says you are in Maidstone in Kent, if so you are very close to Stevenson. I would suggest you take your car to Stevenson (Steve Garlic) who is a very experienced MB indie (having worked for MB Maidstone/Turnbridge for many years before setting up his indie garage).

 

[Justintyme]

The Stop/Start function on my 2013 car with the original MB batteries (both main and auxiliary) still works as it should.

The Stop/Start function stopped working around two years ago (green light on the ECO button on the dash went off), a scan showed a failed Brake Vacuum Sensor, this was replaced by Terry at WG (cheap and easy fix), and the Stop/Start started working again and gave me no grief since.

I usually turn-it off at the start of the journey, but whenever I turn it back on, the ECO symbol in the instrument cluster is mostly green, occasionally yellow, which is how it should be.

This also tells me that my original 7 years old battery is still in good shape

Hi markjay, When I ungraded to a 2014 Eclass 220, the rear battery had just been replaced ( I pointed it out on the pre purchase test drive, as the warning light was on) Since then after having one or two unpleasant stop start experiences ( and NOT being a fan of Stop / Start either) I started to switch it off manually each time I started the car. But now, intermittedly, it is not coming up on automatically, which I'm happy about, except if this behaviour is hiding another problem?? Or does it have some kind of behaviour learning process?

 

[markjay]

If the green light on the ECO button no longer comes-on automatically when the engine is started, then there's a fault in the system, and you'll need to have the fault codes read.

Is the main battery sufficiently charged? Did you get a chance to take the car for a longer drive recently - say 30 minutes or more?