12V critical battery fault
 

Anyone had a 12V critical battery fault? Found some reports but nothing concrete as to a solution. VOC technician reset Friday by disconnecting battery for 20 minutes. Was fine on outward journey Saturday morning but upon return, same again. Got home. But now a tortoise symbol again and 5mph. Refused another technician. Being collected Monday and taken to Bells Northampton. Hoping they can offer a permanent fix and restore my faith.

I had the same fault, on call chap said there was a software update to fix it that they can only apply once it’s occurred. Not had it since the update however I’d owned the car for almost 3 years before it first happened so who knows!

I’ve seen people say software update, others say no such update, another say faulty battery control module, another say conductive pins on battery and another something like a “switch” that connects to the battery under the bonnet (albeit mine is in the boot.

Try a look at this previous thread. https://www.volvoforums.org.uk/showthread.php?t=315579

In case anyone sees this with the same issue. There is apparently a technical journal from Volvo and a software update for this. Been a couple of days since and so far so good.

Anyone managed to get a more concrete answer ? Having just happened to my MY21 XC60 B5D, the Volvo Assistance tech said he'd seen it several times before. He went into the boot, checked and said the battery was at 68%, and the car will go into limp mode if <70% charge. He said that value cannot be changed but aware it is probably a software update to fix the "problem". He ask if we'd been doing more start/stop journeys....which we hadn't. He charged the battery for 10 mins and we were on our way. It has been fine for a few days now.
I didn't ask, stupidly, whether it was the 48v battery, or the 12v. I am assuming it is the 48v, in the rear, and as that is the mild hybrid stop/start battery...but then why does the display say "12v battery. Critical charging fault" ?

Can’t tell you which battery but the message on mine said 12V. The software update has definitely cured mine. Ask your Dealer to lookup the technical journal for it.