Eco Stop/Start inoperative w204

[merc07]

Igniton on - Orange eco dash light is on
Start engine - 5 secs later it turns off, as does the light on the eco button which then has no function either.

It's as if the car has no eco function at all.
This happens about 99% of the time.
It started a couple of years ago but has steadily been getting worse to the point it almost never works at all now.

If I switch the engine off/on, sometimes the light may stay on and eventually turn green after a few miles.

I have had both Mercedes and an indy look at it, both say they can't find a reason for it as there is no codes stored.

The ecu is on the latest software.

 

[MancMike]

Your auxiliary battery in the boot knackered?

 

[merc07]

Auxillary is under the bonnet ??
The main one in the boot reads about 12.4v after a weekend of no use, the small one under the bonnet was more like 13v I think...

 

[merc07]

Auxillary is under the bonnet ??
The main one in the boot reads about 12.4v after a weekend of no use, the small one under the bonnet was more like 13v I think...

I do have an amp connected up to the front battery could that cause any problem - mahbe as you say it's just in it's way out... ?

The only issues I have read about are the battery as you suggest and the aux battery relay ?

 

[ash59fifty-uk]

Does it on my van when I have heaters on full pelt, lights on music blaring- battery power

 

[merc07]

What van ?
It does seem worse in winter - wether that is because of lower temperatures or the fact that the lights are always on ??

Guess I need to get the batteries checked out somehow...

 

[Deleted member 6183]

I do have an amp connected up to the front battery could that cause any problem - mahbe as you say it's just in it's way out... ?

The only issues I have read about are the battery as you suggest and the aux battery relay ?

Have you tried it with the amp disconnected?

 

[merc07]

I originally thought the aux batt was in the boot where I have another amp fitted. This is the main batt and seemed to read a little low.

I tried it for a week with that one disconnected a while back but as the aux batt was reading ok I never actually tried it with the front amp unplugged...

I'll have to check but I think the amp is conncected to the harness that comes from the rear battery so that should be ok..

 

[ash59fifty-uk]

What van ? It does seem worse in winter - wether that is because of lower temperatures or the fact that the lights are always on ?? Guess I need to get the batteries checked out somehow...

VW transporter. Infact, my Caddy also did this