hi all , 

 

i have a 1.6 diesel octavia estate 66 plate . i thought the battery went flat. i called the aa out who said the battery needed replacing, the aa man said i had to get a new stop start battery or the stop start notification  would appear and it would fail its MOT in a couple of weeks . 

 

i went to halfords who sold me a stop start battery and ive just installed it and the warning appears every time i start up the engine. 

 

the aa man said if this alert is present it will fail the MOT . 

 

is there anyway to turn it off guys ? 

 

grateful for any advice

Hello, welcome to the forum.

I recall the stop/start warning being worded as -'Stop-Start unavailable' ,or something similar - is that the warning you get? AFAIK - (and I stand to be corrected) that is not an MOT failure point.

A few questions -

- Was the new battery adapted (coded) to the vehicle when it was replaced?

- Was the alternator tested at the time for correct output?

- Was the correct type of battery fitted?

 

It needs to be coded into the car.  As such, until that is done, the alternator won't charge and you will be left with warning lights.

Find somebody with ODBEleven or VCDS (genuine) local to you.  Details are on this forum.

1 hour ago, varaderoguy said:

It needs to be coded into the car.  As such, until that is done, the alternator won't charge

 

Untrue and scaremongering, yes making the changes to the coding will be beneficial but the battery will charge and in time the Battery Management System would recognise the new battery characteristics and adapt accordingly anyway.

 

Did you mean to right "won't charge correctly"?

@PetrolDave Can you confirm my belief that stop/start unavailable is not an MOT fail?

There would be a hell of a lot more threads on here with people trying to fix it if it were.

AA man is probably harbouring the mistaken idea that any fault light is a fail. Never been true AFAIK, though often claimed.

13 hours ago, noely_cos said:

hi all , 

 

i have a 1.6 diesel octavia estate 66 plate . i thought the battery went flat. i called the aa out who said the battery needed replacing, the aa man said i had to get a new stop start battery or the stop start notification  would appear and it would fail its MOT in a couple of weeks . 

 

i went to halfords who sold me a stop start battery and ive just installed it and the warning appears every time i start up the engine. 

 

the aa man said if this alert is present it will fail the MOT . 

 

is there anyway to turn it off guys ? 

 

grateful for any advice

What exactly is the warning you are getting? Pic if possible.

19 hours ago, J.R. said:

Untrue and scaremongering, yes making the changes to the coding will be beneficial but the battery will charge and in time the Battery Management System would recognise the new battery characteristics and adapt accordingly anyway.

 

Did you mean to right "won't charge correctly"?

Not untrue and not scaremongering.  For a VAG vehicle that you don't update the BMS info for a new battery, the alternator will just sit there at 12.2V and not correctly charge at 14V.

I've replaced two batteries on two Skodas recently (a 2015 and a 2019) - and both followed that methodology.  Ultimately, the car will do one of two things; either throw an alternator charging error or just run down the battery to an unusable value.

On 10/12/2024 at 17:48, Warrior193 said:

@PetrolDave Can you confirm my belief that stop/start unavailable is not an MOT fail?

Since I'm not an MOT Tester I can't confirm that.

6 hours ago, varaderoguy said:

Not untrue and not scaremongering.  For a VAG vehicle that you don't update the BMS info for a new battery, the alternator will just sit there at 12.2V and not correctly charge at 14V.

That's not what several other members who have fitted new batteries without coding have posted over the last few years? They claim everything works as normal and the new battery charges OK?

 

You're the only person who has posted that not coding after fitting a new battery leads to the alternator not charging...

7 hours ago, varaderoguy said:

Not untrue and not scaremongering.  For a VAG vehicle that you don't update the BMS info for a new battery, the alternator will just sit there at 12.2V and not correctly charge at 14V.

I've replaced two batteries on two Skodas recently (a 2015 and a 2019) - and both followed that methodology.  Ultimately, the car will do one of two things; either throw an alternator charging error or just run down the battery to an unusable value.

 

That is implausible, perhaps you drew the wrong conclusion.

 

12.2v is the voltage which a the battery (mis)management system of a stop start vehicle would maintain the state of charge to allow regenerative charging, it is also the voltage that someone would measure taking a multimeter reading across the battery terminals without realising that they need to force a shut down of the active canbus controllers by manually closing the bonnet catch, locking the car then waiting 20 minutes before taking a true reading without the volt drop of all the active controllers.

Edited 11 December, 20241 yr by J.R.

 

13 hours ago, PetrolDave said:

 

You're the only person who has posted that not coding after fitting a new battery leads to the alternator not charging...

Hold on a second.  Unless I am missing something here - I am advocating that you DO (i.e. positive) code in a new battery.  I never said not to code in a new battery.

On 10/12/2024 at 15:08, varaderoguy said:

It needs to be coded into the car.  As such, until that is done, the alternator won't charge and you will be left with warning lights.

 

5 minutes ago, varaderoguy said:

I am advocating that you DO (i.e. positive) code in a new battery.  I never said not to code in a new battery.

Nobody is saying that you said not to code a new battery - the point of difference is what happens if you don't code a new battery.

 

Read your earlier post - you said that NOT coding will lead to the alternator not charging - this IS NOT TRUE.

 

We are all saying that the coding needs to be done after changing the battery, but you are saying if you don't then the battery won't charge - but what actually happens is that the battery DOES still charge but it takes time for the BMS to realise a new battery has been fitted and to adjust its charging regime to take best advantage of the new battery.

25 minutes ago, PetrolDave said:

Read your earlier post - you said that NOT coding will lead to the alternator not charging - this IS NOT TRUE.

okay - honestly not what I've experienced.  As previously stated, I've recently had to change out two batteries on two MK3's - a 2015 non FL and a 2019/20 FL.  In both cases, the BMS just sat there - and the alternator refused to charge the battery.....and that happened over a period of 20 mins or so.  New EFM/AFM matting stop/start batteries will generally come with 60% charge from the shop and you will never get a stop/start battery to charge over 80% anyway and that if you don't code in a battery, then the alterator will not behave in a normal manner and won't charge up the battery. So I am advocating that you risk the BMS getting confused and (clearing up my wording) - you may be left with warning lights (again experienced with another member who asked me to change out their battery - and we watched their [Fabia] get terribly confused over the battery change with no coding.

 

I suppose that if the BMS relearning it profile, then that's a win for all concerned.  For stability though, always code in a battery.  

 

I recently had an AGM Battery replaced on my 1.6 Diesel Karoq by a battery specialist in Stockport. They plugged something into the OBD port which was connected to a battery to maintain power to the Car. Swapped out the battery, disconnected the OBD device and off I drove. No coding required and no problems whatsoever with the Stop Start nor any warning lights since.  Halfords don't know what they are doing.

20 minutes ago, varaderoguy said:

As previously stated, I've recently had to change out two batteries on two MK3's - a 2015 non FL and a 2019/20 FL.  In both cases, the BMS just sat there - and the alternator refused to charge the battery.....and that happened over a period of 20 mins or so.  New EFM/AFM matting stop/start batteries will generally come with 60% charge from the shop and you will never get a stop/start battery to charge over 80% anyway

 

So what you observed is 100% normal for a stop/start car, you simply misinterpreted it, you would never see the charging voltage rise above that figure with a new battery which will have been charged to 100% and maybe lost a little while in stock but no way down to the 80% that the BMS will try to discharge it to.

 

27 minutes ago, varaderoguy said:

New EFM/AFM matting stop/start batteries will generally come with 60% charge from the shop

 

Thats something else you are making up to suit your misguided belief.

 

There is a probably 0.6v error in your voltage readings through multimeter error and volt drop from the engine running and all the canbus controllers etc as the battery is not charging, - you were right about that but not your conclusion as to why.

 

A new battery delivered through a modern short supply chain will never have less than 90% S.O.C.

39 minutes ago, varaderoguy said:

you may be left with warning lights (again experienced with another member who asked me to change out their battery - and we watched their [Fabia] get terribly confused over the battery change with no coding.

 

That happens whenever you disconnect a battery on one of our vehicles unless you use a plug in standby power source.

1 hour ago, Beerhunter17 said:

I recently had an AGM Battery replaced on my 1.6 Diesel Karoq by a battery specialist in Stockport. They plugged something into the OBD port which was connected to a battery to maintain power to the Car. Swapped out the battery, disconnected the OBD device and off I drove. No coding required and no problems whatsoever with the Stop Start nor any warning lights since.  Halfords don't know what they are doing.

Coding is recommended, so why didn't they code it?

I presume that as the Battery fitter had continuous power to the ECU when they swapped batteries that the ECU is fooled into thinking it is the same Battery. Ergo, no need for recoding.

1 hour ago, Beerhunter17 said:

I presume that as the Battery fitter had continuous power to the ECU when they swapped batteries that the ECU is fooled into thinking it is the same Battery. Ergo, no need for recoding.

That's not the way the BCM works, maintaining the power only prevents transient faults being generated when the battery is reconnected, which will all clear themselves after a short drive anyway - any battery faults that may be restricting charge from the alternator to the old battery will NOT be cleared by maintaining power while the battery is replaced - nor will any material changes to battery type or capacity be registered to the BCM.