Main issues will be health / charge of starter battery. Ambient temperature or engine temp

 

This is just off the top of my head, so by no means a comprehensive list, but the conditions that need to be satisfied goes something like this:

Vehicle speed
Driver seat belt buckled
Battery charge state
Ambient temperature
Coolant temperature
Heated windows
Climate Control conditions met, temperature, humidity, a/c compressor
Main battery temperature
Steering wheel load
Engine run time
Battery current draw status (eg heated seats, wipers)
Vacuum status
Bonnet closed, driver door closed
Incline & rolling


But as the poster in post #2 says, 9 times out of 10, it will be one of the 2 batteries (Starter or Aux) that need replacing.

 

Work your way through all these threads for the answer:

See:

Start/stop (again!)

I know this has been discussed before, but I'd welcome views on my specific case. The auto start/stop hasn't cut the engine off at idle this year on my A250. Typical use, 15 miles to work in the morning, 15 miles home. Often short evening trips each evening. Weekends, mainly local, 10-20...

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and

Auto stop start & collision prevention Failed.

So today my Auto Stop/Start has stopped !. Does not work at all. Just a yellow A with a line through it. Also noticed at the same time that the Collision Prevention system has stopped. No more red light when you get close to a car. Called my dealership and they are fully booked for the next 3...

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Get this! easy fix

If your not driving like a loony all the time and happen to be pottering around in comfort mode with stop start on. You look down and hmmm stop start isn't working. Try this go inflate your tires to 42 in the front and 33 in the back. Hey presto it worked!! 3 months thsts been broken for. Weird car

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Stop Start - DCT - I didn't know that

Apologies if you know already this When your using stop/start and when engine is stopped, you can restart the engine by pulling either paddle without brake HOLD releasing, car thinks your in manual change mode and cancels stop/start process

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Stop start inconsistant

Hi everyone, bought my first Mercedes in June this year a new A 250 AMG have had many audi's in the past and always wanted a Merc,, really pleased with the car in general but have already had the wipers replaced (very noisy) and the stop start stopped working after a few weeks when it had not...

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Start Stop Issues

Does anyone know how to engage the ECO start/stop function? I am on manual. It says: Leave the engine's ECO start/stop function switched on, so that the engine can switch itself off when stationary in traffic. Manual transmission: follow the gearshift recommendation when stationary and shift...

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Start Stop - Doesn't always start!

I drive an A180d with the automatic 7 speed gearbox, always on auto. Almost never touch the paddles. It has 35.000 km on the odometer, still in factory guarantee until Feb 2018.I am having problems with the Start - Stop system. Every now and then, the engine stops when I am at the traffic light...

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Flat battery!

My car wouldn't start today, barely clicked over. I measured the battery voltage and it was sitting at 8v !!! Last night I managed to leave my running lights on for a couple of hours. I ddnt think that was possible as I assumed that they allways timed out. I got the road assistance service out...

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Eco stop/start not working

Hello, this is first post so this could go one of 2 ways? I’ve had my 2016 A class 2.1 A200d for around 2 months and I absolutely love it! Only problem is my stop start has stopped working, I take it a blast down the motorway for 1-2 hours and it don’t come on until the end of the journey, 20...

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New battery may be needed - questions

Just checked the standing and running battery voltages. Both are lower than I would like to see. A new battery may be needed soon. Two questions: 1) Which make and spec should I look for? Members experiences, and recommendations please. 2) Is it easy to change the battery DIY, or are...

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Battery need changing?

I have a 66 plate diesel A-class for close to a year and only at the very beginning the auto start/stop worked. The only other time was when I was driving from Northmptonshire to Newcastle that it came up after 75% of the route had been done. Anyway the car was to be serviced yesterday at an...

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Welcome to the forum.

We don't know the mileage of your car or the type of drives you do.

While we're in the warmth of the summer it won't be too much of an issue getting the start/stop to work after a long drive but it will likely need a battery replacement by winter. I'm sure I read somewhere when I had my W176 A45 that the battery life for the car was expected to be 5 years.

 

Wondering if anyone can help me? A few weeks ago my stop start symbol took ages to activate and it would only work when heaters and etc wasn’t turned on, now when I get in the symbol shows for a few seconds then just disappears, even the button doesn’t have a green light on even when I press it nothing happens. Asked a colleague at work and he said it looks like I need a new battery and the battery is only got the capacity to run the car and more vital things? Any help would be appreciated
Thanks all

 

Wondering if anyone can help me? A few weeks ago my stop start symbol took ages to activate and it would only work when heaters and etc wasn’t turned on, now when I get in the symbol shows for a few seconds then just disappears, even the button doesn’t have a green light on even when I press it nothing happens. Asked a colleague at work and he said it looks like I need a new battery and the battery is only got the capacity to run the car and more vital things? Any help would be appreciated
Thanks all

I find on my low mileage A45s the start stop takes a long time to start on these cold frosty mornings. I normally go around ten miles or so before it starts working and even then, the engine might restart while standing at lights or stop start traffic.

 

See all the posts and linked threads above for stop start issues.

Plus this more recent one

Start-stop function working for anyone of you? W176 2018

Hi all owners W176. Just simple Q is it working Start-Stop system on your car? On my not still yellow crossed A Main battery charged no DTC in ECU.

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Hi all.

I recently purchased a 2016 200d AMG Line Premium automatic on 51K miles. It's my first Mercedes and I'm still familiarising myself with everything.

I have a question about the Auto Stop/Start feature. Since I've had the car (5 days as I write this post) it has never turned on, always showing the yellow A strike through symbol on the dash which I think means it's enabled but not all conditions met.

I've tried turning off the AC, driving in Eco mode, going for long journeys etc but it doesn't seem to want to kick in. I thought maybe the auxiliary battery might be low but there's no faults in the dash.

Is there anything else I can try before I take it back to the stealership?

Thanks in advance.

 

Hi all.

I recently purchased a 2016 200d AMG Line Premium automatic on 51K miles. It's my first Mercedes and I'm still familiarising myself with everything.

I have a question about the Auto Stop/Start feature. Since I've had the car (5 days as I write this post) it has never turned on, always showing the yellow A strike through symbol on the dash which I think means it's enabled but not all conditions met.

TL;DR - one or both of your batteries will need replacing.

 

I replaced the Main battery as it was at 25% health when tested. My stop start symbol was showing green but once the engine shut down it would not restart as the ignition went off. I ended up replacing the Aux battery as well and now it works as expected.

 

It would help others if you could mention the battery make and price.

 

It would help others if you could mention the battery make and price.

It would help others if you could mention the battery make and price.

I bought EXIDE 115 AGM CAR BATTERY 80AH 800A AGM800 EK800 Start-Stop which was £127 from Battery Group
And Exide EK151 AGM Auxiliary Car Battery for £55 from Tanya batteries.
Both online

 

Does anyone know if you can disable the stop/start on a permanent basis?
It's very annoying.

 

Just wait a year and it'll stop on its own once the battery starts giving up

 

Has anyone’s battery got so flat it’s not started the car? I’ve had a “critical level and discharged battery” warning a couple of times but it’s always started

 

I've had that but it's always started.