I am getting this error occasionally when engaging Dynamic Mode. If I turn the car off and back on again, it seems to work fine. Everything else seems to function properly, so I don't believe it is a battery issue, though I still need to check. I do let the car sit in my garage most of the time, but I try to drive it at least once every week or two, weather permitting.

She's in otherwise great working condition, 38,000 miles and even the dealer can't find anything to rip me off to fix/replace when I take it in for regular maintenance.

Any ideas what might cause this?

Thanks.

 

You’ve already answered your question, lack of use. Charge the battery overnight and then see how it goes. If you are going to leave it in the garage then it would be wise to invest in a battery maintainer.