XC90 T6 - 2018 12v Battery service required warning

[davod8]

XC90 T6 - 2018, had the small auxiliary support battery changed at a local battery shop.

After it was changed we get a dash board warning ⚠️- “12v system service required”

It has a code for the Battery Monitoring sensor comms - CEM B11DB87.

I have tried a BMS reset, but disconnecting both batteries and the two plugs to the BMS module and waiting 30mins - But still have the error.

Tested both batteries, all are good. Checked all the connectors a few times.

Anyone had the same issues - Looking for ideas?

[OldEngineer]

I found the BMS needs a 'kick' to sort out the monitoring. A short charge on the front connectors does it.

[TheBing]

I just got the same issue on my XC90 D5 - 2016 after having it towed to my Volvo dealer who replaced a bad steering lock.

⚠️- “12v system service required”
Or in swedish: ”12v system service erfordras”

The messages appears after approx 30 sec after every start. The auto start/stop does not activate since I got this warning (which is not a great loss).

Main battery measures 12,74 V
Auxillary battery measures 12,65 V
The generator puts out 13,5V over the main battery terminals when it is charged to 12,74 V.

The car runs just fine both long and short distances and the batteries seems to get charged as they should.

I have tried to trickle charge the batteries over night with my Ctek charger. Still gets the message.

I have checked all connectors so they are tight.

I have disconnected the negative connector on the main battery for 15 min. Still gets the error.

The wrecker tried to give my car some extra juice with cables from the tow truck when dealing with my car which at first only had a bad steering lock (said that sometimes it helps). Can this have caused the issue?

Thanks for any thoughts and ideas what to do?

[TheBing]

The cause for my car:
Unconnected BMS-sensor on the main battery.