New Battery, Bad BMS Code, cleared codes, low battery charge

[Vorlockfoss]

Hi, I'm looking for help with installing my new battery.

I have just replaced the old Exide battery on my 2009 Audi A4 B8 2.0 TFSI Quattro as it was showing 20% charge, 0Ah and only 11.6 volts available, seemingly no matter how long I drove for.  I did try charging it with a slow charger, and got it to 40%, but no more.  At this time my car had gone into 'energy management active', and although my engine would crank apparently easily, it would not fire at all.

The battery suggested by Varta, and bought, is a "Varta A7 - E39 - MPN 570901076 - 70Ah/760A - AGM Battery", which is the same specification as the Exide I've just removed.  Now, according to the sticker in my Audi Service Schedule, the 'Starter' battery for my car was 'J0B', which was a "92Ah/520A AGM Battery", according to what I've learned online anyway; I'm open to correction if I'm wrong.  Anyway, I fitted the new Varta battery, changed the last digit of the serial number of the previous BMS Code via VCDS, saved and cleared the error codes.

I have to say that I have no idea what values the current code in the BMS represents, but it may be incorrect.  Obviously I can't use the original Starter Battery BMS code, otherwise my car may try to charge the new Varta battery to 92Ah and damage it, IMO.  I am trying to establish the correct code for my new Varta Battery, but it's proving quite difficult.  As is known, the code needs to be 10 or 11 digits long, but the MPN on my new Varta is only 9 digits long.  I have searched high and low, but each time I'm presented with the same manufacturer part number '570901076', which is only 9 digits long as I stated.  I have tried adding 3 spaces to fill the missing digits between it and 'V0A', but no go, VCDS will not allow it; a 10 digit serial is tagged on the end as required.  As I previously stated, the code installed may not be the correct code because, even though there is no error code showing in the log (see next paragraph), the dashboard is still displaying a 'low battery charge' and my car still will not start; it just turns over & does not attempt to fire.

Just to add some context to the above, I was having issues with very rough running, which came on all of a sudden last week, rendering my car undrivable.  Aside from the reasonably violent engine vibrations, I was seeing a considerable amount of white smoke leaving the exhaust and drastically reduced power.  After thorough investigations I was satisfied my head gasket is intact.  Incidentally, the white smoke did not smell very nice, but not 'eggy' as would be expected with the CAT; it was a combination of bad smell & petrol I think.  I also smelt petrol in the oil filler, and coupled with a low fuel pressure error code and much research I concluded the High Pressure Fuel Pump needed replacing.  I installed a brand new Hitachi HPFP, which has made a difference to the consistency of the rough running, i.e. less erratic.  After further investigations I concluded the PCV had most likely failed, maybe in relation to the HPFP failing.  I therefore installed a new PCV (oil separator), and a fuel pressure sensor while I was at it, but my engine has not started since; the installation of the PCV & Sensor/Sender is around the time my car power state changed to 'energy management active'.

My opinion is, I need to install the correct code for my new battery & car combination, or at least equivalent code i.e. 70Ah / 700A / AGM.  As I've previously mentioned, I suspect the code installed may be incorrect as I have been seeing power issues on my car for over 2 years; I don't know in what context the code may be wrong, but it would make sense, especially considering the persistent low battery charge error on my dashboard.  To add, the battery is only 4 years old and I've only driven an average of 4k miles each year.

Any help, thoughts or opinions would be gratefully appreciated, and a correct code would be blooming marvellous...!!!

Thanks for your time.

Paul.

[cliffcoggin]

My guess, and it is only a guess, is that VCDS will not accept the code for your new battery because it is the wrong capacity. Why have you fitted a 70 Ah battery when Audi wants 92 Ah?

[Stevey Y]

15 hours ago, Vorlockfoss said:

Hi, I'm looking for help with installing my new battery.

I have just replaced the old Exide battery on my 2009 Audi A4 B8 2.0 TFSI Quattro as it was showing 20% charge, 0Ah and only 11.6 volts available, seemingly no matter how long I drove for.  I did try charging it with a slow charger, and got it to 40%, but no more.  At this time my car had gone into 'energy management active', and although my engine would crank apparently easily, it would not fire at all.

The battery suggested by Varta, and bought, is a "Varta A7 - E39 - MPN 570901076 - 70Ah/760A - AGM Battery", which is the same specification as the Exide I've just removed.  Now, according to the sticker in my Audi Service Schedule, the 'Starter' battery for my car was 'J0B', which was a "92Ah/520A AGM Battery", according to what I've learned online anyway; I'm open to correction if I'm wrong.  Anyway, I fitted the new Varta battery, changed the last digit of the serial number of the previous BMS Code via VCDS, saved and cleared the error codes.

I have to say that I have no idea what values the current code in the BMS represents, but it may be incorrect.  Obviously I can't use the original Starter Battery BMS code, otherwise my car may try to charge the new Varta battery to 92Ah and damage it, IMO.  I am trying to establish the correct code for my new Varta Battery, but it's proving quite difficult.  As is known, the code needs to be 10 or 11 digits long, but the MPN on my new Varta is only 9 digits long.  I have searched high and low, but each time I'm presented with the same manufacturer part number '570901076', which is only 9 digits long as I stated.  I have tried adding 3 spaces to fill the missing digits between it and 'V0A', but no go, VCDS will not allow it; a 10 digit serial is tagged on the end as required.  As I previously stated, the code installed may not be the correct code because, even though there is no error code showing in the log (see next paragraph), the dashboard is still displaying a 'low battery charge' and my car still will not start; it just turns over & does not attempt to fire.

Just to add some context to the above, I was having issues with very rough running, which came on all of a sudden last week, rendering my car undrivable.  Aside from the reasonably violent engine vibrations, I was seeing a considerable amount of white smoke leaving the exhaust and drastically reduced power.  After thorough investigations I was satisfied my head gasket is intact.  Incidentally, the white smoke did not smell very nice, but not 'eggy' as would be expected with the CAT; it was a combination of bad smell & petrol I think.  I also smelt petrol in the oil filler, and coupled with a low fuel pressure error code and much research I concluded the High Pressure Fuel Pump needed replacing.  I installed a brand new Hitachi HPFP, which has made a difference to the consistency of the rough running, i.e. less erratic.  After further investigations I concluded the PCV had most likely failed, maybe in relation to the HPFP failing.  I therefore installed a new PCV (oil separator), and a fuel pressure sensor while I was at it, but my engine has not started since; the installation of the PCV & Sensor/Sender is around the time my car power state changed to 'energy management active'.

My opinion is, I need to install the correct code for my new battery & car combination, or at least equivalent code i.e. 70Ah / 700A / AGM.  As I've previously mentioned, I suspect the code installed may be incorrect as I have been seeing power issues on my car for over 2 years; I don't know in what context the code may be wrong, but it would make sense, especially considering the persistent low battery charge error on my dashboard.  To add, the battery is only 4 years old and I've only driven an average of 4k miles each year.

Any help, thoughts or opinions would be gratefully appreciated, and a correct code would be blooming marvellous...!!!

Thanks for your time.

Paul.

Hi you could have used the existing BEM code and just changed the last THREE digits or just made up any ten digit code you can even use a row of zeros it wont make a lot of difference, as for the battery type you can put in UNK for unknown, I do find it strange they recommend a replacement that has a lower amp hour rating but a higher cranking rating, I would guess that part of the fuel problem may be the lift pump in the tank whenever that goes wonky the first thing it suggests is that the HPFP is at fault, check the lift pump flow on live data when running if its over 600 at idle the pump is on its way out or more often than not they just fail, easy way to test is get a false fuel supply tank connected above theHPFP so gravity is forcing the fuel down in to the feed pie and then try starting it.

Steve.

[Vorlockfoss]

Hi cliffcoggin,

Thanks for your response.

10 hours ago, cliffcoggin said:

My guess, and it is only a guess, is that VCDS will not accept the code for your new battery because it is the wrong capacity. Why have you fitted a 70 Ah battery when Audi wants 92 Ah?

This is true, but it's more to do with the MPN of my new battery being only 9 characters long, when the BMS will only accept 10 + 1 space or 11 characters in length.

I fitted the battery I have because every configurator suggests that battery, such as Varta (varta-automotive), Amazon, carbatterymarket, eurocarparts, and others.  There is one, Tanya, that suggested the Varta A5 which is 95Ah, but as all the others suggested the A7 which is 70Ah, I chose that by popular suggestion.  It wasn't until my engine continued to fail to start after I'd installed the A7 battery that I looked further into the suggestion of using the cars 'starter battery', which I learned was a 92Ah 520A.  This is when I posted as above.

I would normally suggest it was my own stupidity, lol, but not on this occasion.  😆

Thanks again,

Paul.

[Vorlockfoss]

Hi Stevey Y,

Thanks for your response.

4 hours ago, Stevey Y said:

Hi you could have used the existing BEM code and just changed the last THREE digits or just made up any ten digit code you can even use a row of zeros it wont make a lot of difference

Indeed, I'm sure I did, but I believe I only changed the last digit & not the last 3.  I've now learned that about the serial number, so that will come in handy.  🙂

4 hours ago, Stevey Y said:

as for the battery type you can put in UNK for unknown

I don't believe you can on my A4 B8 as it's non-UDS.  You can only enter 10 or 11 digit part number, 1 or 2 spaces, the battery manufacturer, 1 space and then the 10 digit serial number.

4 hours ago, Stevey Y said:

I do find it strange they recommend a replacement that has a lower amp hour rating but a higher cranking rating

Yes, me too, but every battery supplier, aside from Tanya, suggested a 70Ah 760A battery, so I went by popular suggestion.  As I said to cliffcoggin above, it wasn't until my engine continued to fail to start after I'd installed the A7 battery that I looked further into the suggestion of using the cars 'starter battery', which I learned was a 92Ah 520A.  This is when I posted as above.

4 hours ago, Stevey Y said:

I would guess that part of the fuel problem may be the lift pump in the tank whenever that goes wonky the first thing it suggests is that the HPFP is at fault, check the lift pump flow on live data when running if its over 600 at idle the pump is on its way out or more often than not they just fail, easy way to test is get a false fuel supply tank connected above theHPFP so gravity is forcing the fuel down in to the feed pie and then try starting it.

Apologies, I should have clarified that I changed the pump in the tank around 3 years ago, less than 12k miles ago, for a new Bosch pump, so that shouldn't be an issue.  I haven't physically tested it, which I will do tomorrow, but it's making all the right noises, at all of the right times and instances.  There is a simple way to test the flow of that low pressure pump, by disconnecting from the HPFP and adding a plastic 500ml bottle; it should reach around 1/3 full when opening the door and after emptying, it should reach a little under 2/3 full when pressing the key.  So watch this space on that.

Thanks again,

Paul.