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ECO light yellow all the time

S

sceh

Active Member
Joined
Jul 31, 2015
Messages
273
Car
w123 240TD
2011 W204 180 CDI

The eco light on the dash seems to stay yellow all the time now. I rarely use this feature but I am intrigued. It doesn't matter if I have done 500 miles or 5, winter or summer.
I have Carsoft and found no DTCs although it does not make specific reference to the ECO system.
I was told it could be the auxiliary battery but if so, how come there is no DTC or warning message and how come it could be duff since it is so rarely used.
ANy ideas about how to diagnose this?
Thanks
 
The Eco light is green on mine, it’s the engine management light that is yellow :oops:
 
sceh said:
The eco light on the dash seems to stay yellow all the time now. I rarely use this feature but I am intrigued. It doesn't matter if I have done 500 miles or 5, winter or summer.
Click to expand...

It's generally the main (starter) battery not being completely healthy ... often due to the car being left standing at some point rather than driven regularly. Our W205 was an ex-demo and needed a new battery when we got it at just over 12 months old. The only symptom was the eco light being yellow, although the Mercedes Me app did report the battery as being 'partially charged' all the time (in the 'service' menu).
 
battery plus there are alot of parameters to tick the boxes b4 it will turn green.
 
And lo and behold, after months where it has always been yellow, last night it tuned green! Go figure...
 
sceh said:
And lo and behold, after months where it has always been yellow, last night it tuned green! Go figure...
Click to expand...

Warmer/drier/brighter weather, so using less electrical power to start the engine and while driving (lights, heated seats, demist, etc.) ... which may help a slightly weak battery reach full charge.
 
definitely a battery issue. Mine was like that, I replaced both the aux battery and main battery (as eventually my brake hold function also stopped)

Wish I hadn't though, the Eco stop start system is awful.. worst thing on the car by miles... It should be renamed from Eco stop start to "Bloody Annoying Stop start system"!

However I have trained the kids to switch it off every time.. so all is good now LOL
 
Does anyone have a definite list of EXACTLY which conditions need to be met for it to work?. Why, for example, does the internal temperature matter?
ta
 
sceh said:
Does anyone have a definite list of EXACTLY which conditions need to be met for it to work?. Why, for example, does the internal temperature matter?
ta
Click to expand...

its all to do with the car if it thinks it cannot perform a restart then the eco will not engage, my insignia was the same. Imagine it doing an eco stop then not been able to restart itself :)
 
sceh said:
Does anyone have a definite list of EXACTLY which conditions need to be met for it to work?. Why, for example, does the internal temperature matter?
ta
Click to expand...

Vehicle conditions for the automatic engine stop or start
In a few countries, the ECO start/stop function is not available in any drive program due to the available fuel grade, regardless of the display in the multimedia system display.
Conditions for the automatic engine stop:
  • The ECO start/stop function is activated.
  • The outside temperature and atmospheric air pressure is within the range that is suitable for the system.
  • The engine is at normal operating temperature.
  • No engine diagnosis is active.
  • The engine speed is within the range that is suitable for the system.
  • The automatic transmission fluid temperature is within the range that is suitable for the system.
  • The temperature in the vehicle interior is within the set range.
  • The fuel tank is sufficiently filled.
  • The system detects that the windscreen is not misted up when the air conditioning system is switched on.
  • The charge level and the voltage of the battery are sufficient.
  • The battery temperature is within the range that is suitable for the system.
  • The engine bonnet is closed.
  • DSR is not activated.
  • AIR BODY CONTROL does not raise the level.
Conditions for the automatic engine start:
  • The vehicle starts moving.
  • The brake system requires a running engine.
  • The temperature in the vehicle interior deviates from the set range.
  • The system detects moisture on the windscreen when the air conditioning system is switched on.
  • The battery's charge level is too low.
 
Chili said:
Vehicle conditions for the automatic engine stop or start
In a few countries, the ECO start/stop function is not available in any drive program due to the available fuel grade, regardless of the display in the multimedia system display.
Conditions for the automatic engine stop:
  • The ECO start/stop function is activated.
  • The outside temperature and atmospheric air pressure is within the range that is suitable for the system.
  • The engine is at normal operating temperature.
  • No engine diagnosis is active.
  • The engine speed is within the range that is suitable for the system.
  • The automatic transmission fluid temperature is within the range that is suitable for the system.
  • The temperature in the vehicle interior is within the set range.
  • The fuel tank is sufficiently filled.
  • The system detects that the windscreen is not misted up when the air conditioning system is switched on.
  • The charge level and the voltage of the battery are sufficient.
  • The battery temperature is within the range that is suitable for the system.
  • The engine bonnet is closed.
  • DSR is not activated.
  • AIR BODY CONTROL does not raise the level.
Conditions for the automatic engine start:
  • The vehicle starts moving.
  • The brake system requires a running engine.
  • The temperature in the vehicle interior deviates from the set range.
  • The system detects moisture on the windscreen when the air conditioning system is switched on.
  • The battery's charge level is too low.
Click to expand...
The temperature in the vehicle interior is within the set range

why this condition?
 
^^ For passenger comfort - if the engine is off then it will take longer for the cabin to heat/cool to the correct temp.
 
tode said:
^^ For passenger comfort - if the engine is off then it will take longer for the cabin to heat/cool to the correct temp.
Click to expand...
For me this is usually the condition that is preventing my Start/Stop from functioning - in Hong Kong, even the winter temp is normally quite mild in comparision to the UK (normally feels like a bad summer's day in London), so the enginer and gearbox get up to normal temp within a few minutes of the car being started in the morning. However the start-stop wouldn't function at the first set of traffic lights unless I raise the cabin temp control momentarily to match the outside temp. Otherwise the start-stop wouldn't function until the air con cools the car down to the temp I have set.

In the hot summer the start stop almost never function unless I do this since the air con takes a very long time to cool the cabin to the desired temp.
 
Thankfully my cars do not have this function . But pretty much every single hire car I use has it . I was in a petrol VW for 10 days recently , amazing how quickly you can train yourself (in an unfamiliar car) to make this the first button you push once the engine starts...to switch it off.
 
Mine is green instantly,as soon as the car is started. Which is a good thing,as it highlights the need to turn it off.
 
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