2019 V90 Petrol - 'Critical 12 Volt Charging Fault'

[nu11eaf]

It might be worth doing a reset as per the attached video link, it might work with your problem too, its worth a try and nothing to lose. https://youtu.be/Nkv4hQgDUII?si=yW8KUwd2oiDuLIpj

[Gozza6]

Thanks. My garage have tried resetting any number of times having ascertained the two batteries and alternator are functioning properly, though I'm unsure if they followed the method used in the youtube video.

I'll give it a go when I can as, like you say, I've nothing to loose.

No feedback here on the 'switch' that I've come across in an old link so I'll keep digging.

[Gozza6]

Reset did not work. Car starts and drives perfectly normally and no hint of going into crawl mode or stopping dead. Message remains there after the initial alert on start-up.

Contacted my nearest Volvo dealership in Stoke-on-Trent and explained all I could. The switch mentioned on this forum could, according to Volvo Stoke, be a BCSM (Battery Control Support Module).

They need to undertake an initial diagnosis for £145 (inc VAT) after which they can tell me what is needed and how much it will cost.

I'll probably have to bite the bullet but has anyone come across a BCSM? If so can you tell me what it is please?

Thanks

[Lexman8]

The BCSM is the module in the attached pic. It's primary function is to control charging and enable the power supply to be divided between the main battery and secondary battery. It can also connect the secondary battery on detection of any voltage drop to ensure no loss of functionality in the car.

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[Gozza6]

Originally Posted by Lexman8

The BCSM is the module in the attached pic. It's primary function is to control charging and enable the power supply to be divided between the main battery and secondary battery. It can also connect the secondary battery on detection of any voltage drop to ensure no loss of functionality in the car.

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Thanks Lexman8. I had done a bit of research since posting and found the same image and had a quick look.

Is this a 'switch'? Perhaps it is.

One of the possible fixes for my ongoing problem of the message not disappearing, seems to be as follows:

....locate the BCM, (battery control module), with a wire going to it. Unplug the wire and leave for a minute or two, then plug back in.

Has anyone any experience of doing this? Or should I be cautious of attempting such an approach?

I suppose what disconnection then re-connection does is simply interrupt the electrical charge to the Support Battery. I'm just not confident of doing this without someone having done it before or telling me it won't affect anything! Also I thought there were two connections, so which one?

Any further help welcomed.

[Gozza6]

Car has been with dealership for 'diagnostic assessment'.

Software updated but this was not the solution.

Apparently the '12v battery critical charging fault' it is a wiring issue which requires further investigation. The power when the car is running is low somewhere on a set of wiring linkages which cannot be isolated from diagnostics alone. The foot movement sensor under the rear bumper and tyre pressure connections are on the same run as are others on this problematic wiring section.

It returns to the dealership next Thursday for (hopefully) a fix, whatever that may be.