2019 V90 Petrol - 'Critical 12 Volt Charging Fault'

[Gozza6]

Warning light came on today (Saturday) for the first time and advised to stop. Fortunately I was only yards from my drive. Had a service and MOT done (regular garage used for years but not a dealership) 5 days ago so thought of bad battery connection. It wasn't.

Called AA. Mechanic tested charge of starter battery and that was fine but his analysis machine said the battery needed replacement. (?) He couldn't understand the reading as the car clearly started sweetly as usual. He then thought it might be the alternator but reckoned it could also be software, a connection, or the battery. He reckons it needs a diagnostic assessment as driving may not be guaranteed beyond maybe 10 miles.

Has anyone on here experienced the same problem? If so, what was the solution?

The car has only done about 41,500 miles and the battery (in fact everything) is original.

Thanks in advance for reading and any replies.

[OldEngineer]

Don't think the AA man has given you enough data (or enough testing for you)

The car thinks the battery is critical but the car starts and drives
The AA Man tested the battery and found something?

My guess is the BMS (Battery Management System) is confused. It's located on the main battery. I sorted a similar problem by charging at the front port (by the Support Battery)

Others have just disconnected the main battery and found the BMS resets.

[neilgorin]

Sounds like an alternator about to fall. Older cars without all the unhelpful panic messages would just put up a red battery light when that happened and it'd often go out at high revs.

Although if it's still on original batteries at 5 they're probably at their end anyway.

[sda2489]

We have alot of these problems with our work cars (XC90 and V60) B6 engines. Battery needs charged.

It can sometimes be the alternator belt snapping. You'll soon know if it's that.

T.

[Gozza6]

First, thanks for your comments.

Car is currently in the garage where I usually have it maintained. They told me that diagnostics were run prior to service to alert them of issues and there were none.

Alternator and belt were part of this check and are working fine. They suspected starter battery issue but once placed on trickle charger over night it is holding it's charge and seems fine. Support battery checked and that seems fine too so I'm not sure what the AA mechanic was picking up but he wasn't over-confident of his machine.

I'm passing on your comments to the garage, especially the BMS stuff, but I'm now wondering if there is a sensor or cable that might be causing problems. I can't see a software update would make any difference although that hasn't been done for 3 years.

I'll update this thread when I know more.

Thanks again.

[ian77]

Is it the same error as in this thread?

https://www.volvoforums.org.uk/showt...58#post2777858

This one was a known issue and a software update seems to solve it.

[Gozza6]

Thanks Ian77, the fault is probably the same though I suspect there may be a number of issues that could cause this fault. I have never even had so much as a battery warning before. In fact the only warning message I have seen in my driving experience of this car has been for tyre pressure (apart from the annual Service messages).

Update from my garage - Starter battery and Support battery are now showing full charge and when the ignition is on they are both receiving additional charge from the alternator. The garage (in which I have 100% faith in, having used them for decades) believe there is no actual problem with the charging but are now unable to eradicate the message which continues. They believe that the AA readings were either an anomaly or the machine used is up the spout.

The car has been returned but will go in again on Friday when their analytical guru returns from holiday.

The problem with calling this out as a 'software update issue' is that were this to make sense, the car would have to be new or newish. Why should it happen to my car (of approaching 5 years old) when the last software update I had was over two years ago. It is so easy to be told by a dealership 'we have completed a software update' when nothing has been done other than the fault messaging element being reset.

Interestingly another AA mechanic dropping a car off at my garage today said he had seen this so many times before but there is no obvious problem and the car is perfectly drive-able. He wondered why someone thought a car needed a battery management system when they performed well enough without them. Basically he was suggesting that there are too many unnecessary sensors and systems on modern cars. He was positively scating about electric vehicles.

So we move forward to Friday when I hope I can provide a final update.

[neilgorin]

Originally Posted by Gozza6

Interestingly another AA mechanic dropping a car off at my garage today said he had seen this so many times before but there is no obvious problem and the car is perfectly drive-able. He wondered why someone thought a car needed a battery management system when they performed well enough without them. Basically he was suggesting that there are too many unnecessary sensors and systems on modern cars. He was positively scating about electric vehicles.

He's absolutely right.

As I said up there, older cars showed a red light when your alternator was not charging and it didn't start in the morning if the battery was knackered and had failed during a cold night. Both without a message.

As for the AA man and electric cars, you should have heard the rant a Volvo Assist mechanic went on when I asked his opinion about them - he was pleased to come out to my car that had "just a bad misfire for a change" - I wonder if there are any breakdown boys who have a good word to say.

[Gozza6]

Car collected this morning by my garage and I was given an interesting bit of information that some may already know.

Garage owner says speaking to Volvo this fault is common among a range of post-2018 models and they (Volvo) are aware of it.

He was told some Volvo owners have replaced both starter and support batteries and the alternator with no effect on the warning message either being shown or reoccurring later.

Some seem to have had software updates with variable results. Basically there seems no logical solution and in between the recent car collections by my garage it has performed as well as it usually does. No problems with start-up (even when the AA mechanic originally suggested there should be!).

I'll update when my car is returned but it begs the question of, if these are 'critical' warnings, and are known to Volvo, why can't they be more obviously solved and what is Volvo doing about informing owners of solutions or efforts to resolve the fault message being flagged up?

It could be coming to you any day!!

[Gozza6]

Car returned by my garage but the warning message is still showing despite the car being drive-able and not showing signs of slowing down or stopping dead. Battery reset carried out with car left overnight in garage.

To recap: Batteries tested and holding charge; Alternator working as it should; Car starts as it always has and drives without any other problems being flagged up.

Next step: To contact Volvo dealership and ask for software update, explaining the reason (which should be obvious). I'll also ask about the 'switch' solution that some on here have mentioned, though I'm not sure what this is exactly.

Could this switch be a bypass to one of the starter battery sensors??

I'll let you know whether this gets resolved. Thanks for your interest.