Dennis
This forum is full of references to low battery (Parasitic Drain) in respect of causing irregular readings and codes on Jaguars.
The advice, as always, is invest in a CTEK MS 7 or MS 10 charger / re-conditioner . Use it at least once a month for at least 24 hours and (even with a new battery) you will probably experience less numbers of annoying codes / warnings etc, due to battery discharge.
Best Wishes and Regards, John