Stop start not working

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Did you mention a problem with ss at time of service? Most garages will not interrogate every system for faults during a routine service.
 
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Altamar

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Did you mention a problem with ss at time of service? Most garages will not interrogate every system for faults during a routine service.
To be honest, no, partly because I was not then convinced there was a problem, and also partly because I assumed any error code would show up. I have deliberately done a few long journeys since to eliminate the possibility that short journeys were causing the issue. Your comment is helpful and I will take it back to them over the next week or so and see what they say.

At least I have found the aux battery in the boot now!
 
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Quick update.

I was literally half a mile away from MB dealer to ask them what they thought when the ECO word on the dashboard went green and SS started working again! I suppose that's better than it starting to work ten seconds after I had arrived at the garage...

I had just completed my third two-hour round trip on a motorway in ten days so maybe the battery has recharged sufficiently? I have to confess I don't like it when electric/electronic problems "fix themselves" for little apparent reason and I suppose I am still a little suspicious as I thought I was doing a reasonable mix of local and motorway driving before.

As an aside, I put a voltmeter on both batteries earlier this week and the aux was around 13.5v and the main one was nearer 12.4v.

So, I am not going to rush out and spend a couple of hundred on new batteries just yet and I am not sure I can take it back to MB while it is currently working but I will update this forum as things develop over the next few months.

Thanks again for all your helpful replies.
 

Tony Dyson

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Quick update.

I was literally half a mile away .... As an aside, I put a voltmeter on both batteries earlier this week and the aux was around 13.5v and the main one was nearer 12.4v.

Thanks again for all your helpful replies.

Manufacturers Data would suggest that at 12.4v your main starter battery is currently working at between 50-75% capacity, nothing wrong with that! your Start/Stop battery in the boot indicating 13.5v is a false high being elevated by (I suspect) a back feed from a Capacitor Bank supporting the Stop/Start function.
I have been unable to find a circuit diagram to confirm the source of the back feed but know it exists as I have found 13.3v on my connected battery, back feeds of varying voltages when disconnected and once some load is applied to the SS battery it soon drops to more realistic voltages <12.3.
 
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Hi all, a quick update. The Stop Start remained very intermittent in becoming available and so I did the maths.

Taking it into a MB dealer to ask them to plug it into a diagnostic tool was likely to cost upwards of £70, maybe as much as £140, and then if they suggested a new aux battery was necessary I would be paying MB prices for a battery plus labour.

Or I could take a punt based on the majority of the replies to my original post, buy a new auxiliary battery online for less than £50 and fit it myself.

So last Friday I bought and fitted a new aux battery. There wasn't much of an immediate improvement to be honest but as the week has progressed, the stop start has become available quicker and quicker and I am currently thinking it is now operating as designed. I am guessing the first few days with the new battery needed time to get it fully charged but that is only supposition on my part.

Anyway, I think THE PROBLEM IS FIXED and I am grateful for everyone who replied.

On my late 2014 facelift E220 Bluetec saloon the aux battery is in the boot, secured by a bracket held in place by one 10mm bolt. I decided there was no need to add a temporary 12v feed before disconnecting the battery, and I seem to have got away with that.

Thanks all.
 

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Good result from where we were in post 3....glad it’s sorted now you can enjoy it.
 

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covered before....

if you care about the engine then stop start broken is good, if you want to wear out the planet, stop start functioning is great
its sells lots more cars, (or cam chains, batteries, alternators and engines)

I have just been driving a car with stop start and as I already knew it just highlights how dangerous it is. In cut and thrust driving it introduces a lag in getting going. Some cars are better (merc) and others very dangerous (audi).. The Hyundai DSG boxed thing I was driving stole a huge chunk of the safety margin I work too (by 50 to 66%), at best meaning I inconvenienced others on two occasions, in a situation where the driver may already have misjudged it could kill someone.
 

jaguar306

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I have a C220 2014 which is the 2015 model and I have the same issue. Initially it was a warning and is was for the auxiliary battery (Stop Start Capacitor) which was changed. I drove from the UK all the way to the Black forest in Germany and it only went from Amber to green a couple of times. I drove to Aberdeen from Aylesbury and it still remained Amber. MB dealership state its fine and diagnostics show no errors or faults. They simply quote "Various Parameters" need to be met for it to function and maybe I do too many short trips. I bet new c class ones work however. Annoying and if the amber light was not there it would be ok but you have to cancel it everytime you change setting on stability. Crap.
 

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I have a C220 2014 which is the 2015 model and I have the same issue. Initially it was a warning and is was for the auxiliary battery (Stop Start Capacitor) which was changed. I drove from the UK all the way to the Black forest in Germany and it only went from Amber to green a couple of times. I drove to Aberdeen from Aylesbury and it still remained Amber. MB dealership state its fine and diagnostics show no errors or faults. They simply quote "Various Parameters" need to be met for it to function and maybe I do too many short trips. I bet new c class ones work however. Annoying and if the amber light was not there it would be ok but you have to cancel it everytime you change setting on stability. Crap.
Aberdeen to Aylesbury... short trip... MB do spout some drivel at times :rolleyes:
 
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I have a C220 2014 which is the 2015 model and I have the same issue. Initially it was a warning and is was for the auxiliary battery (Stop Start Capacitor) which was changed. I drove from the UK all the way to the Black forest in Germany and it only went from Amber to green a couple of times.

I started this thread and thought the issue was fixed in the autumn when I fitted a new aux battery. Unfortunately the improvement was short-lived and I was back to square one after two months.

I took it to a local Indy last month and they said the main battery was in a poor condition (one on a scale of ten) and so it was replaced even though the car was starting well and I did not have any error messages or other symptoms. This appears to have cured the issue... so far!!
 

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E350 Petrol. Aux battery in the boot. Main battery up front.
Start/Stop not working. Also, noticed the break hold not working.
Dealer wanted £718 to repair..... Suggested to replace both batteries and also a battery sensor.
What I did.... Replaced aux battery myself. 10 minute job for £100. Didn't solve the problem. Replaced main battery myself. 60 minute job and a real pain. Very awkward battery position. Battery £196. After 10 mins of driving, both start/stop and break hold started working again.
So, if you have the same problem, get the main battery checked for free somewhere and if they say it needs to be replaced, start with that battery.
Good luck
 

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Hi all.

I've noticed the stop start on my 2014 E Class 220d has stopped working. I am aware there are "many variables which need to be satisfied" before it operates and the word "ECO" is constantly amber on the dashboard - I believe this has to be green before all the "variables" are correct.

I do my fair share of short journeys but have also done at least two two-hour motorway round trips in the last week in the hope that the battery would recharge (if that was the issue), DPF would regenerate etc etc but there's been no change to symptoms.

The car was in MB for a full service three weeks ago so presumably any error codes/battery problems would have been picked up then? I've got the ME adaptor installed and that suggests battery voltage is currently 14.7v

I also know many people will think I am fortunate and they wish theirs would stop working but I want the car to work as designed (and that's without getting into the debate about saving fuel at standstill and lessening emissions in town etc).

Is this a sign that the battery is about to die, for example? Is there a way of resetting the system?

Any suggestions to cure the problem appreciated please.
Are you using sport mode? on my car stop start doesn't work in sport mode.
 

mupson

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Are you using sport mode? on my car stop start doesn't work in sport mode.
Have your main battery checked. When mine stopped working there wasn't a fault code and the dealer wanted £718 to replace two batteries. Initially I changed the Aux battery in the boot (£100). That didn't help. Then I had the main battery tested at Kwikfit and found it to be faulty. Didn't install one of the Kwikfit batteries in the end. Ordered an OEM replacement (£196) and installed it. Eco start / stop AND break HOLD worked within 15 minutes of driving. Good luck
 

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Hope this may help somebody, I bought my W205 (67 plate) back end of April, drove it 200 odd miles from the dealer & never noticed the light not changing from yellow to green to indicate the stop start was active. Recently had to do another long distance run and noticed again it never changed. This was on top of countless small journeys so booked it in at local MB dealer who diagnosed battery wasn't holding charge. To meet the used warranty criteria, they had to keep it overnight and charge the battery to see if it held it's charge. It didn't, new battery fitted this AM & stop start now working. It doesn't seem to like it when the air con is on at the beginning of the journey but a few miles into the journey, I can engage the air con & then the stop start works as it should.
 

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Hope this may help somebody, I bought my W205 (67 plate) back end of April, drove it 200 odd miles from the dealer & never noticed the light not changing from yellow to green to indicate the stop start was active. Recently had to do another long distance run and noticed again it never changed. This was on top of countless small journeys so booked it in at local MB dealer who diagnosed battery wasn't holding charge. To meet the used warranty criteria, they had to keep it overnight and charge the battery to see if it held it's charge. It didn't, new battery fitted this AM & stop start now working. It doesn't seem to like it when the air con is on at the beginning of the journey but a few miles into the journey, I can engage the air con & then the stop start works as it should.
I don't suppose they gave you the old battery? There's quite a few who'd like it to replace their "working"battery... ;) :cool:
 

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:D Sadly not! Oddly enough, straight through to the coffee area. plastic bag wrapped key handed back and very politely (to be fair) ushered back to my car (covid n that of course).
 

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