Start stop not working on b class

[RichieL]

2014 b class start/stop not working Please help guys!
I have a late 2014 b class and the start stop never goes green (yellow) on dash! I’ve changed the aux battery and drive the car plenty, I’ve been to the dealership for help, but they only seem to be interested in “a hours diagnostics @£162” does anyone out there know what could be up with it? The car starts, stops and drives 100% perfect, I look after her and know about the parameters.... ambient temp is fine, no fogged up windows, no ac on, no short trips, in e mode, new aux bat and main bat is in good health with ample charge/amp/crank power
Please please please help!

 

[Gazwould]

Congratulations , it's a desirable thing to have Stop Start inoperable .

 

[whitenemesis]

Without diagnostics, one's just guessing.
Find a good independent with STAR, much cheaper than dealer..

 

[RichieL]

Congratulations , it's a desirable thing to have Stop Start inoperable .

Come on, please......

 

[rayaans]

If DPF is nearing clogged then it won't stop/start

Take it on a motorway drive for 1 hour and see what happens

 

[fifermerc]

Has it worked until recently, or are you saying it has never worked? My car is different, an E class, but the same principle I suppose, and I find that especially at this time of year my ECO indicator is very reluctant to go green, sometimes even disappears altogether and only comes back next time you re-start the engine. What kind of driving are you doing? If mainly short city runs that won't help. As suggested above, try a good run, and have your aircon off and as little electrical load as you can get away with.

 

[RichieL]

If DPF is nearing clogged then it won't stop/start

Take it on a motorway drive for 1 hour and see what happens

Go on the motorway most days.... long runs and get up to good speed....as my good friend Johny five says “input, need input!”

 

[RichieL]

It’s wo

Has it worked until recently, or are you saying it has never worked? My car is different, an E class, but the same principle I suppose, and I find that especially at this time of year my ECO indicator is very reluctant to go green, sometimes even disappears altogether and only comes back next time you re-start the engine. What kind of driving are you doing? If mainly short city runs that won't help. As suggested above, try a good run, and have your aircon off and as little electrical load as you can get away with.

its worked, I would say 4 times in the last year, only going green after driving for 8 hours or so non stop.... I drive the car every day and where I live is countryside so very little city driving, leave the house, 1 mile drive on a 30 limit, then 50 then motorway. When it has gone green, it’s gone green for one set of lights then the engine starts up and the light goes yellow again. I’m so ocd, and it niggles the flip out of me..... just like things to work the way they’re bent to.

 

[Gazwould]

Bent to alright .

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[grober]

I'm going to guess its something to do with battery voltage / alternator output never reaching a certain "threshold" but there are other possibilities. Couple of "off the wall" ones among many possibilities ! faulty bonnet switch or not enough pressure in the brake servo system? The W246 stop/start system is fairly unique in that it can use a combined belt driven starter/alternator. Some talk of said starter/alternator used to brake-position the engine such that a selected piston is ready to fire to minimise the starting load, but can't verify that!

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[RichieL]

Thanks for all your reply’s, I guess I could check the bonnet catch switch, maybe give it a clean, you never know might be a load of dust/ leaves clogging it. The battery’s are both good with great charge, great ampage, great crank and the alternator is doing it’s job. It’s really niggling me and don’t really want to just start pouring money at the dealers......

 

[Deleted member 126251]

I've found that if my car has stood for a while (week) ....it takes a really long drive to get the eco working again. Have you tried connecting a battery charger overnight? Just make sure it is suitable for your batteries.

 

[RichieL]

Tried this

 

[Gazwould]

What does your smart battery charger start off at and charge to ?

My C Class is 11.7 V to 12.1V so quite poor hense I've lost Stop Strain

It's not slow to start or anything , just wondering how much longer it will last.

 

[ioweddie]

Get yourself a Ctek Battery Conditioner / Charger....The main battery under the bonnet needs to be at max for stop start to work...if your driving about most of the time with the heater and lights on etc...the car is busy building the main battery up to charge....which deletes the stop start function....That's what happens on my S205 anyway...

 

[RichieL]

Main battery when I check a couple of months ago was 13.6v, I’m not really a heating person have the stat set to 21 and fan speed at 2.5, never use heated seats, and I’m super boring listening to only talk radio when I drive so no banging tunes or bass. That is going to zap the battery...... arrrgggghhhh this is driving me nuts

 

[Dickie Fix]

In the low temperatures we're having at the moment, I wouldn't worry about it. My B, which I've had for 3 years, rarely goes 'green' during the winter, even on a long run despite it being garaged and connected to a Ctek overnight. Come the warmer weather, I expect it to spring back into life and turn 'green' after a mile or two. Last summer it was turning 'green' after just a few hundred yards from a cold start, so there can't be much wrong with it.

 

[whitenemesis]

You appear to be enjoying this..
You seem to have done everything anyone suggests, except getting the codes (if any) read using STAR/Xentry
If it's really annoying you this much have a drive along the coast to MBS in Southampton or PCS in Hornedean. Both well respected and vastly experienced MB independents who will be able to either put your mind to rest, or sort out any issues. Cheaper than the dealerships or counselling

 

[RichieL]

Hi not enjoying at all, just appealing to anyone that might know or have been through this before I start handing out cheques to mb for £162 p/h plus parts..... so they can tell me “it might be this or could be that”

 

[whitenemesis]

I start handing out cheques to mb for £162 p/h plus parts..... so they can tell me “it might be this or could be that”

Which is why you have been advised to go to an MB independent who will be much more reasonable and attentive.