12v system service required?
 

Latest warning / error to present itself to me. Have found scant reference to this in this forum, other than battery needs charging or take car for a long drive. I trickle charged the battery last night and is showing full, it was low.

I get the warning every 5 mins or so.

Any ideas?

This may be the final straw for me.

Edit 2021 XC90 T8 w/ polestar for reference.

Online manual also no use in giving any info. I’m lucky to be able to speak to my local Volvo service dept, even to book a service, so not confident they will be able to help me all that much.

Correct me if I am wrong, but your car should be still on warranty, just book in warranty repair and they should take care of it. I also 2021 T8 with Polestar, but XC60 version, and I don't intend to worry myself much if such problem arises, a warning light of any kind on the dashboard is their job to take care of and do the repair under warranty.

You are right. However with all of these things it is the inconvenience of having to take time off of work and away from family to deal with these things. Through previous bad experiences my confidence in the car service world is unfortunately low.

I’m conscious I’m posting similar info on my issue which is touched upon in a number of threads. By posting I always hope that it might be useful for someone in the future who has a similar problem.

To summarise and update on some findings:

- post 12v system service message I connected my CTEK trickle charger via front terminal points under bonnet of my 21 XC90 T8. Indicated state of charge was low and overnight my CTEK was showing a full charge.

- that day I drove ~30 miles mostly in AWF and PE modes and received constant 12v system service requirement messages every few minutes.

- on getting home I plugged my CTEK charger directly to the rear battery and to my surprise was showing as low. Again I left it charging overnight and was showing fully charged by this morning.

- I’ve not received any more error messages all day since directly charging the rear 12v unit. I have purchased an eyelet adapter for my charger with the traffic light system to show state of charge. Curiously after fitting it was showing as amber “in need of a charge”. I got my multimeter out and measured the voltage on the rear battery at 12.54v. 10 mins later it was 12.24v and registering as red on the adapter (in desperate need of charge) which seems really weird, given the car was off, only the boot was open.

- after driving the car in PE mode (deliberately to engage the ICE) for another 20 miles or so the adapter shows green and the multimeter is reading 13.40v across the battery.

I’ve no clue what is going on here, I’ll need to speak to Volvo about it I guess. On the face of it it appears I’m suffering huge battery drain for some unknown reason, enough to go from fully charged via CTEK to ~12.2v in the same day.

If anyone has any ideas I’m all ears.

Thanks

Further update for anyone who has interest.

Car booked in for service and investigative work on 4 weeks time, as soon as Marshall could fit me in.

Gent on the service desk advised trickle charging from the main battery and not from the terminals under the bonnet(!), contrary to advice in other threads.

Voltage of my battery continues to be all over the shop. Was 12.5v before a short run in Pure mode, and 13.5v after, so battery is clearly receiving charge whilst driving, but then seems to drop quite rapidly whilst not in use.

Starting to question the state of my 12v battery…

To my understanding, you will be provided with a replacement loan vehicle while your car is in the repairs. So, technically, the entire thing is only two occurrences when you have to drive to the dealer - once to give them the car, and once to get the car back. In between, you will drive a loan car. That's how I understand it, although I have not had a warranty repair as of yet, so correct me if I am wrong.

Sure. The largest car the dealer has to loan is an S60, though they have 3 XC40s so I guess naturally more likely.

I couldn’t care except I’ve got 3 kids to cart around and with a newborn all the clobber that needs to go in the boot, so as our main family car an extended stay with Volvo would be an inconvenience to put it mildly.

12v battery reading 12.24v and CTEK says in desperate need of charging.

Is it not worth trying someone other than Marshalls? I put them in the same category as Stoneacre.....

Sadly I have a service package with Marshall’s so somewhat loathed to now take it elsewhere. My time is something of a scarce commodity and realistically I don’t have time to yo-yo to Bedford and back unfortunately.

If Marshall’s can’t sort it I think I will move it on.

Further update. Having been showing 12.24v last night (car not used), I used the car to commute to the station this morning and I preheated it. I took a measurement before I left; 13.96v.

Philip, you clearly do many, many more miles than I do and I’m wondering if that has a bearing. Clearly my 12v battery gets charged during use / preheating, which as far as malfunction issues goes, has to be a good thing. I try to do most of my driving in Pure and my car has been slowly installing a nav map upgrade a few percent at a time, so maybe that has been taking its toll?

I will save all of you my adhoc battery level reading updates and see what Volvo say in a months time and will continue to charge the 12v battery, if needed, directly from the battery per advice I received from Volvo service (given charging from the terminals in the front bonnet appeared not to work as anticipated).

Thanks for the help.