2016 w205 C Class start stop function not working after new battery install

[Jon1956]

Hello, newbie here, and apologies if this has been posted previously, but I am unable to find any relative information on this forum. OK, so that being said here is the problem my car is encountering:
the Start Stop function has not worked for a little while, the circled "A" remains yellow. On a recent service at the dealership, I was informed that the battery would require replacing. This was done yesterday by myself, a "like" for "like" AGM 80Ah 800. The car was then driven a couple of miles but still no start stop function (the battery was charged prior to installation). Am I missing something here ie coding the battery into the car? Any assistance would be gratefully accepted. Stay Safe.

 

[Gazwould]

This is excellent news .

 

[Jon1956]

This is excellent news .

Please explain, thanks

 

[GeeJayW]

This is excellent news .

?? Seems a bit harsh, unless you mean not having stop/start active is a good thing. In which case I agree as I always turn it off anyway.

OP, there are a number of conditions that have to be met before the stop/start function works. Driving a couple of miles won't do the trick.

 

[Jon1956]

?? Seems a bit harsh, unless you mean not having stop/start active is a good thing. In which case I agree as I always turn it off anyway.

OP, there are a number of conditions that have to be met before the stop/start function works. Driving a couple of miles won't do the trick.

Ok thanks, under todays circumstances I'm unable to give the car a 20 mile run, I'll just hold off for a while, then hopefully it can be given a decent run out. I've had another Merc a few years ago (62 plate) and it worked fine and I kind of got used to it and liked the system around town. Thanks for the input anyway mate, much appreciated.

 

[Mikesmith29]

Most stop/start systems use battery condition, ambient temp, engine temp and any thing like aircon and rear heated screen being on to determine whether to function or not.

 

[Jon1956]

Most stop/start systems use battery condition, ambient temp, engine temp and any thing like aircon and rear heated screen being on to determine whether to function or not.

Ok Mike, thanks...seems a rather odd way of operating a system, but it is what it is, sadly.

 

[Mikesmith29]

It to ensure the battery doesn't go flat and engine gets up to temp quickly.

 

[Petrol Pete]

Hello, newbie here, and apologies if this has been posted previously, but I am unable to find any relative information on this forum. OK, so that being said here is the problem my car is encountering:
the Start Stop function has not worked for a little while, the circled "A" remains yellow. On a recent service at the dealership, I was informed that the battery would require replacing. This was done yesterday by myself, a "like" for "like" AGM 80Ah 800. The car was then driven a couple of miles but still no start stop function (the battery was charged prior to installation). Am I missing something here ie coding the battery into the car? Any assistance would be gratefully accepted. Stay Safe.

Great result !!

 

[AMGeed]

Hello, newbie here, and apologies if this has been posted previously, but I am unable to find any relative information on this forum. OK, so that being said here is the problem my car is encountering:
the Start Stop function has not worked for a little while, the circled "A" remains yellow. On a recent service at the dealership, I was informed that the battery would require replacing. This was done yesterday by myself, a "like" for "like" AGM 80Ah 800. The car was then driven a couple of miles but still no start stop function (the battery was charged prior to installation). Am I missing something here ie coding the battery into the car? Any assistance would be gratefully accepted. Stay Safe.

I believe your car has a capacitor which acts as an auxilliary battery to operate the stop/start system.
Some cars (my E class for example) have a second battery and some have a capacitor.

I would get this checked and think its the cause of your stop/start system being inoperable despite changing the main battery.

This is a useful read.

Mercedes-Benz Auxiliary Battery Malfunction Explained

Are you facing auxiliary battery malfunctions in your Mercedes Benz? Click here to have the detailed knowledge!

xenons4u.co.uk

 

[Jon1956]

I believe your car has a capacitor which acts as an auxilliary battery to operate the stop/start system.
Some cars (my E class for example) have a second battery and some have a capacitor.

I would get this checked and think its the cause of your stop/start system being inoperable despite changing the main battery.

This is a useful read.

Mercedes-Benz Auxiliary Battery Malfunction Explained

Are you facing auxiliary battery malfunctions in your Mercedes Benz? Click here to have the detailed knowledge!

xenons4u.co.uk

I have been wondering if that may be the cause, despite the local dealership stating it wouldn't be, as I've had no warning from the car saying that there is an auxcillary malfunction. Thank you.

 

[T5R+]

OP - have you been across to the introduction section and said hello? Worth it.

The fact that your stop-start has not functined for a while points toward a faulty stop/start OR auxillary battery on the decline. If latter, eventually the brake-assist-hold would have ceased to engage. Other tell tale signs are parking and radar sensors. Not all cease to work simultaneously - unless unlucky.

Suggest that you have the AUX battery checked and reread the dealership paperwork, as may say it on the report.

Look on the bright side - you now have a new main battery.

 

[Jon1956]

OP - have you been across to the introduction section and said hello? Worth it.

The fact that your stop-start has not functined for a while points toward a faulty stop/start OR auxillary battery on the decline. If latter, eventually the brake-assist-hold would have ceased to engage. Other tell tale signs are parking and radar sensors. Not all cease to work simultaneously - unless unlucky.

Suggest that you have the AUX battery checked and reread the dealership paperwork, as may say it on the report.

Look on the bright side - you now have a new main battery.

I will have it checked out. I had the battery checked a couple of weeks ago, which also proved to be failing ie it wasn't holding charge, hence that's why I went with the main battery change in the first instance and eliminate that side of the problem. Thanks for your pointers, much appreciated. I will also say hello in the intro section very soon.

 

[wongl]

Hello, newbie here, and apologies if this has been posted previously, but I am unable to find any relative information on this forum. OK, so that being said here is the problem my car is encountering:
the Start Stop function has not worked for a little while, the circled "A" remains yellow. On a recent service at the dealership, I was informed that the battery would require replacing. This was done yesterday by myself, a "like" for "like" AGM 80Ah 800. The car was then driven a couple of miles but still no start stop function (the battery was charged prior to installation). Am I missing something here ie coding the battery into the car? Any assistance would be gratefully accepted. Stay Safe.

A couple of points to consider for ECO Start/Stop...

1) As mentioned before, the car needs to meet a long list of conditions before the ECO Start/Stop icon on the display will go green. From my limited experience, the key ones are

a) Engine temp must be at least 60 degrees (your car being a diesel, it is highly unlikely that your engine temp would have reached 60 degrees from a cold start after a couple of miles unless you were driving it in second gear!)​

b) Cabin temp must be reached at least once since start-up (the best way to satisfy this is to turn off your air-conditioner and turn down the cabin temp to meet the ambient temp)​

c) The main and aux batteries need to have sufficient charge to manage a start/stop cycle (did you charge up your new battery overnight with a battery charger before installing it in your car?)​

2) Since the aux battery in the W205 is a capacitor, it should be okay unless there is a error message reporting it as faulty.

a) Interesting to note that on my C300h, a diesel hybrid left permanently on charge with a CTEK Start/Stop charger due to extended periods of being unused, I got an Aux Battery failure message for a few days before it cleared itself after being driven a few days by myself. Needless to say, ECO Start/Stop was not working until the Aux Battery fault cleared itself.​

​

Good luck with your ECO Start/Stop. I hope it will recover itself after a few days of driving.

 

[Jon1956]

A couple of points to consider for ECO Start/Stop...

1) As mentioned before, the car needs to meet a long list of conditions before the ECO Start/Stop icon on the display will go green. From my limited experience, the key ones are

a) Engine temp must be at least 60 degrees (your car being a diesel, it is highly unlikely that your engine temp would have reached 60 degrees from a cold start after a couple of miles unless you were driving it in second gear!)​

b) Cabin temp must be reached at least once since start-up (the best way to satisfy this is to turn off your air-conditioner and turn down the cabin temp to meet the ambient temp)​

c) The main and aux batteries need to have sufficient charge to manage a start/stop cycle (did you charge up your new battery overnight with a battery charger before installing it in your car?)​

2) Since the aux battery in the W205 is a capacitor, it should be okay unless there is a error message reporting it as faulty.

a) Interesting to note that on my C300h, a diesel hybrid left permanently on charge with a CTEK Start/Stop charger due to extended periods of being unused, I got an Aux Battery failure message for a few days before it cleared itself after being driven a few days by myself. Needless to say, ECO Start/Stop was not working until the Aux Battery fault cleared itself.​

​

Good luck with your ECO Start/Stop. I hope it will recover itself after a few days of driving.

I note all your observations on the stop start problem, I'll try to do a longer run out with the car and see if the fault resolves itself. Many thanks indeed.

 

[rf065]

It's a very common fault, the capacitor behind the glove box is the usual culprit. Mine had to go into Mercedes twice before they changed it and solved the problem.

 

[Jon1956]

Hello, newbie here, and apologies if this has been posted previously, but I am unable to find any relative information on this forum. OK, so that being said here is the problem my car is encountering:
the Start Stop function has not worked for a little while, the circled "A" remains yellow. On a recent service at the dealership, I was informed that the battery would require replacing. This was done yesterday by myself, a "like" for "like" AGM 80Ah 800. The car was then driven a couple of miles but still no start stop function (the battery was charged prior to installation). Am I missing something here ie coding the battery into the car? Any assistance would be gratefully accepted. Stay Safe.

UPDATE: Everything is good. After a 10 mile drive the stop/start has now come back "online"...Thank you all for your assistance.

 

[Jon1956]

I note all your observations on the stop start problem, I'll try to do a longer run out with the car and see if the fault resolves itself. Many thanks indeed.

Update: All now working as it should after a 10 mile drive, thank you.

 

[Jon1956]

I note all your observations on the stop start problem, I'll try to do a longer run out with the car and see if the fault resolves itself. Many thanks indeed.

All now working after a 10 mile drive, thank you.

 

[GeeJayW]

Cool...