jetsfan101

so i am a bit confused here. Never have i ever recoded anything after replacing the battery. Granted it was never on a Q7, but cars like A8, A6 (2006-2010)

What would happen if one replaced the battery but did not recode with VAGcom ?

dreadlocks

Yes it is, at least for left drive vehicles.. RHD would be under the pass seat..

Coding resets the battery management system, as the batteries age it lowers the charge voltage so the old battery is not overcharged as it looses capacity through normal wear/tear.. When you install a new battery without resetting the BMS it'll likely be undercharging your new battery.