Audi A4 B8 Battery Replacement and coding using vagcom

[@Japplesnap]

Coding the battery is really about the optimal charging strategy. As the battery ages, the car will more aggressively charge the battery. When you replace an old battery with a fresh new one, the car will continue to charge at a more aggressive charging map unless you code the battery, which pretty much "resets" the charging map back to the beginning again. But you're right----you can just replace the battery without coding it all day every day. You may shorten the life of your new battery a bit if you do that though.

[@seat786]

Spot on, agree with what you've already said. Just to add the alternator will put out a higher voltage/charge to the new replacement battery thinking it's still an old battery, which in turn WILL shorten the life of the new battery & possibly damage the alternator too... To overcome this, coding is always recommended. If your VCDS scan shows fault 03041- 'Energy Management Active' then coding is a must as the old battery has depleted so much that it's triggered the above code & only a new battery, correctly coded will reset it. Of course if the above code is not present when scanned then a new battery will work just fine without any coding required but will shorten battery lifespan.

[@SupersportYR1]

I have an off the shelf Interstate battery in my 09 A4 that I am pushing 7 years next month with and I'm positive it wasn't recoded since it has no OEM serial number.

[@Japplesnap]

@@SupersportYR1 You can make up a number or just change one digit and the car will recognize it as a new battery.

[@philb707]

Finally a explanation on why u need to code the battery, learned something new today

[@lisandro12349]

I'm getting an aftermarket AGM battery for my S5. I don't see anywhere the serial number for coding. Can I use the same numbers found on any other video/photos?

[@chrischesterfield3005]

Just wanted to say thanks. I swapped the battery after sitting all winter. And no one local had a clue as to how to get me the BEM number for the battery. Just changed the last digit and bam it’s all good. Thanks again!

[@VISTATREKKER]

Hey thanks for the video, can I ask which code reader you recommend?

[@Tonil875]

Hi mate I have the same B8, 2.0 TDI. Why did you changed the last digit by 8 when you coded? Regards

[@hn_capone8475]

Ive changed my battery 2 years ago and now since my alternator keeps failing as its unable to communicate with the bcm so i haven codded it yet now i will do

[@james30k]

Great info I have a 2010 audi that I had the battery replaced 9 years ago and the mmi still said 50 percent so I replaced the battery with the same exact battery and without recoding it went back to 100 percent I have the vag-com but I have no codes should I leave it alone or should I change one number and recode it it’s the same exact battery replacement… I never had any codes …hope someone can reach out 🙏🏻

[@Sleepy_Chihuahua]

Good car, good tools, be good if you get you a proper extension

[@touristtea6076]

Thanks for the info! Audi wants $600 to change my battery. I’m like no! Finding the battery was easy. Now I need the system you connected and rest. How can I do that after I have it swapped? System, connect to car etc.

[@CarsandCoding]

You don’t have to do the coding, that is optional. But if you want to do it, look up “obdeleven” or “Ross-tech” for the two options that allow you to get into and change the values in the control modules.

[@wyseave]

Great, if i get a Diehard battery will i be able to recode it even if its not on the OE list

[@CarsandCoding]

Yes you need to replace with same style battery. Do not get lead acid if you have AGM for instance. Then replace last digit of code with a different number. That is all.

[@prodbysyd]

Hey :) I have a Audi A4 B8 2009-2011 1.8T TFSI. I’m trying to buy a new battery but I don’t know which one I have already installed. I do have a Subwoofer, so I’d need to take that out and all. Do you happen to know where I can find the right battery?

[@Ghost_717]

Ok so just to clear up a few things up, I want to change my battery on my B8 A5 because I haven’t yet since owning the car for almost a yr and it’s getting colder outside and I don’t know how old my current one is…I’m not really tech savvy so will not coding a new battery affect my car in any negative way or can the old one just be replaced like any other car?

[@CarsandCoding]

That is the ongoing debate. There is no definitive answer. People will say “I talked to an audi tech and he says you have to code it” other people say “I replaced my battery and it lasted 7 years” The thing is, how long batteries last is more dependent on weather (heat) and if the car is driven regularly or not. A battery can die in 6 months if not driven in winter and it freezes. It can last maximum 3 years in Florida heat, and 7 years in mild climates. I do not think coding has anything to do with battery life. As long as you replace a wet battery with wet and agm battery with agm then you are good. That is my opinion.

[@Ghost_717]

@@CarsandCoding appreciate the feedback

[@EJR20]

Was the old battery (original VW battery) just a standard 12V battery, AGM, or lithium battery?

[@CarsandCoding]

The one I installed was a regular lead acid battery. No fancy stuff.

[@EJR20]

@@CarsandCodingok so that means it’s AGM. Do you know what type was the old battery?

[@OMGitsFLY]

Hey i just installed a sub yesterday in my audi a5 2012 but when i got done to turn on car after about 2/3hrs the car wouldnt start everything works inside just it won’t fire up but when i try to push/start it it comes on but no start but makes clicking noise like battery is dead 🧐🧐 do i need to jump it or since i disconnected the battery for a while it needs to be recoded??

[@CarsandCoding]

Sounds like either the battery is dead (which is likely) or somehow you broke the main crash fuse at the battery that disables the starter in a crash (not likely). Try charging the battery first.

[@OMGitsFLY]

@@CarsandCoding i will try getting a jump start tomorrow morning 🤞🏾

[@kirkmcdonald7429]

Hey can batteries cause my alternator and started to go bad faster than usual? I have yellow top optima batteries in mine

[@CarsandCoding]

Alternator is debatable topic. Starter no way, that is a motor, it either works or it doesn’t. As long as the battery is the right size and power you will be good. If you have a smaller battery than stock or the battery is old or weak the alternator will work harder, which could burn it out.

[@jonmirel3342]

Do i need to do this if i simply disconnect the battery i need to replace a coil connector

[@CarsandCoding]

You can disconnect and reconnect the battery any time. No coding is needed if you just disconnect. Only if you replace the battery.

[@frankw9836]

i replaced my Battery yesterday on my 2008 Audi A6 it was a Varta 110AH and it was still the ORIGINAL 14 years old !!! i bought a 90AH instead of the 110AH but i guess its good enough. I let the engine run while switching over the battery, so i didn't had to do any "re-programming"

[@allenmason4283]

You don't understand the reason for Audi battery coding and your procedure does not eliminate the need to code the new battery.

[@cousinlybows4559]

What machine do you use for the coding on the battery?

[@costaslioupas97]

VCDS

[@calinga2587]

merci

[@deejay4837]

Before you even start you need to realize the B8.5 car does not work with vag-com the way the B8 does. You cannot get into measuring blocks in the B8.5 at all as it's a modules are on a different language called UDS. So the functions are limited. So Ross-tech's vagcom is almost obsolete with the B8.5 or not much better than a good scan-tool.

[@audia4addict950]

When you get out batterie its + after- and when you reconnect its- after +

[@koengeerlings2147]

Thanks!

[@juancarloscarmonagarcia5819]

Hola lo que no entiendo es porque sólo cambia el último ni del código el 7 por un 8?

[@abel1694]

El caro piensa q es una batteria nueva cuando cambias el numero. No la carga tan aggresivo como batteria vieja.

[@EJR20]

Meant to ask if the old battery was AGM. I’m sure it was just being certain.

[@CarsandCoding]

Old battery was lead acid

[@EJR20]

@@CarsandCoding I’m not very good with battery types and I’m trying to charge my A4 battery with a NOCO genius battery charger, it has a mode for a “normal” 12V, AGM, & lithium. Lead acid is the same at Absorbent Glass Mat, no?

[@CarsandCoding]

Normal is lead acid

[@accer555]

Shouldn't this car have an agm battery?

[@CarsandCoding]

I have owned it since new, no AGM in this one. Maybe they started after 2010

[@accer555]

@@CarsandCoding Agree sir, i think that battery type also depends on engine type, does it or doesn't have start stop and so on....mine is 2015 and by the pr label it did left the factory with an agm battery. Cheers

[@CarsandCoding]

@@accer555 For sure the start/stop use AGM

[@petergolden8614]

You replaced your battery with a flooded rather than an AGM. I was under the impression that AGM had to be replaced with AGM downgrading to flooded was not recommended. Not sure what your stock Audi battery was so I am not trying to be critical just trying to determine what I will replace my battery with.

[@CarsandCoding]

My original was not AGM

[@CLUBCRITIC]

This video does nothing for me, how/where are you looking at the codes

[@CarsandCoding]

@@CLUBCRITIC here is the link for the software and cable www.ross-tech.com/