Stop/start service required

[ACanning]

Thanks for your quick reply. I know about the terminals under the bonnet. What is the difference between a 12v and a 12v AGM battery?

[Lexman8]

Originally Posted by ACanning

What is the difference between a 12v and a 12v AGM battery?

Both have a nominal 12v output but an AGM battery has to be charged at a slightly higher voltage than a standard battery.

[Chudy85]

Originally Posted by Clan

Well you tried your best, just change the battery or batteries, the battery monitor will soon build up fresh data as time goes on.

I have an issue that looks like I need to replace the support battery.

In this case, I will disconnect the support battery and negative cable from the main battery will BMS keep in sync or will reset as I have replaced both batteries?
Maybe BMS will find later on which level the main battery was before disconnecting.

[nu11eaf]

For anyone who is having trouble with Stop start service required or resetting the warning message after charging or replacing the aux battery. This video may be useful, it looks like a Volvo tech has made it. https://youtu.be/Nkv4hQgDUII?si=zBkCFpLEFoTxZn5e

[nu11eaf]

If you have a problem with warning after charging watch this video, it shows how to reset the service warning. https://youtu.be/Nkv4hQgDUII?si=w5AkkNpJ0y6sCmvu

[ruttledgemary]

hi all.

does anyone know of any way to disable the start/stop service required warning without replacing/ charging the battery. big ask but if anyone has any tips please let me know. I just need it removed from the dashboard ahead of a driving test tomorrow. thanks

[James77]

Originally Posted by nu11eaf

For anyone who is having trouble with Stop start service required or resetting the warning message after charging or replacing the aux battery. This video may be useful, it looks like a Volvo tech has made it. https://youtu.be/Nkv4hQgDUII?si=zBkCFpLEFoTxZn5e

Seems pretty easy to do following the steps. Changed car batteries loads when I was a kid in the 90s, don't know what it is but cars being more complicated these days changing I shy away from the same procedure even though fairly simple! Just confidence with it I guess.

For main battery read it needs to be coded, is that really true or car just needs to sit without main battery attached for 15-20 mins for it to reset?

[v60mike]

Originally Posted by Usualwill

2016 XC90 D5

Got the dreaded “stop/start service required” last week so asked Volvo to investigate during my service. They advised auxiliary battery was dead (no readings) and main battery showed 65% SOC and that both would need to be replaced at a cost of over £500.
Does this sound right to you, both batteries going at the same time? It’s 7+ years old now so I half expected new main battery might be required but have hardly ever heard of both going? What’s strange is that very occasionally stop/start still works which I don’t think would be the case if the aux battery was dead. I think the dealer is going for the easy option of replacing both.
Any thoughts or tips? I’ll probably look into replacing them myself, any recommendations on what/where to buy?
Thanks.

thats robbery, i paid £80 for main battery, you can get the aux battery for under £50 fit them run the engine then disconnect the bms wire on the battery for 60 sec to reset the bms system plug back in and off you go