Econ Mode.

[Sheffield Col]

When driving in Econ Mode the "A" very rarely turns Green to cut the engine at the traffic lights etc. As I understand it the engine should cut out at the lights / queueing, every time. Do I have a fault ?

 

[Sheffield Col]

Car is 2014 C class Blutec diesel Automatic W205. (should have stated this in first post, sorry)

 

[philsmerc]

Car is 2014 C class Blutec diesel Automatic W205. (should have stated this in first post, sorry)

Hi

I have a Dec 2014 C250 BlueTec AMG line estate (S205) and noticed that as the weather warmed up, the stop/start was hardly going green, in any mode (assumed that with predominantly short runs, cold temps etc during winter, this was normal).

When the car went in for the steering column earth recall, mentioned it and they reported back "the stop/start battery has failed the test and needs replacing".

Having already read other posts about this issue, it seems that the "stop/start battery" is in fact some sort of capacitor/electronic unit (located under the passenger foot-well carpet?).

I have a MB Tier 1 warranty but initially, MB dealer (where I purchased car from) said the warranty didn't cover batteries. I argued that it wasn't technically a battery, but an electronic component that should be covered. Further delving into the warranty booklet revealed that batteries are indeed covered but cynical old me wonders how many customers have been charged wrongly?

Anyhoo, stop/start works fine now, so I will see how it performs during the winter.

Good luck with yours.
Phil

 

[Deleted member 126251]

How often do you drive any distance?

 

[rf065]

"the stop/start battery has failed the test and needs replacing".

I had the same problem, all fixed under warranty.

 

[keith of kent]

I had the same problem, all fixed under warranty.

So did I

 

[philsmerc]

Update to post #3

Fast forward to last Friday and I got a red "Auxiliary Battery Malfunction" message, which then turned to a white message. Everything works okay, including the stop/start, but message hasn't gone away. Rang dealer and it's got to go in for a check on Monday.

Reading various other MB owner's forums (including US ones), it does seem to be a fairly common issue with the W205/S205? I'll be interested to see if it's the component they changed back in May that's cauising the problem or something else?

Phil

 

[littleowl]

I have a W204 and the ECO mode seems to be equally yellow as it is green. Have no idea why, or whether it's faulty - my old car (Citroen) cut the engine every time I was stopped.

 

[philsmerc]

About time for another update:

At the time of the last problem (September), it was again fixed under the MB Tier 1 warranty. I asked if it was the same thing as back in May and was told it was something different (no explanation as to what but I was in a hurry).

I did ring up to ask for a copy of the invoice but was told that I'd have to contact the Tier 1 warranty company. This I did and was told that due to "data protection", I'd have to ask the MB dealership (and take V5C as proof of ownership!).

So I waited until it was due its annual service and MOT and asked for the details of work carried out. They said I could not have copies of the invoices as it was commercial information between themselves and the warranty company! I pressed that it was my car and I had a right to know what work had been done on it. They reluctantly agreed to email me details of work carried out and a fortnight later, got confirmation that in May, they replaced "the battery" (presumably the stop/start battery - that on a S205 is a flux-capacitor thingy) and in September, a voltage converter".

I have come across various posts/videos about both of these items from MB forums far and wide so they seem to be common issues?

Needles to say I've renewed my warranty for the next year (thankfully, it was the same price too).

 

[Mikeone]

It's rely on an additional battery and in those cold times that is normal dont worry about it

 

[Murton]

Some models have the voltage converter/battery unit with the capacitors on it while others seem to have a second battery. I think that leads to confusion. Maybe the larger engines which take more starting current have the additional battery?

The pictures I have seen of the failed voltage converter module show leaking capacitors which is a fairly common fault. You should be able to recondition them by replacing the caps but I haven’t seen a picture showing their values to see how much that would cost.

 

[philsmerc]

Referring back to my earlier posts about the faults with the stop/start system on my S205 (C250 Bluetec)- it's interesting to note that after I purchased the car in June 2016 (it was 18 months old - low mileage), I noticed that once the really cold weather arrived, the stop/start - err, stopped working. At the time, and with a service due late November, I queried this and was told that it was due to the cold temp, short duration trips etc etc.

Seemed sort of logical and for the first year, it did, err, start again when spring sprung. Following year was when it threw its dummy out, as described in my posts.

What I have noticed, having had the flux capacitor bits replaced, is that even with the recent cold snap, the stop/start is still working fine (yippee - or not - depending on if you're a fan or not). Bloody cold and still doing mainly local journeys, so maybe I was fobbed off originally, by the "experts"?

 

[Riva811]

My experience with two mercy's is that if you are revving more than 2k or revving fast then you can forget about the light going green. Also depending on power demand it might not start/stop to protect the battery.