had the battery tested and it said the battery was fully charged. I'm only getting one click. Could it possibly be the starter? I'm a new owner of Jaguar, so I do appreciate the inputs.

 

I would say immobiliser potentially from the description, probably want to look at the fault codes to see what shows up

 

Quite confusing with the title "Battery low warning" Are you getting a warning other than the normal ignition on but vehicle not running on the center media information screen? A single click when trying to press the ignition button while the brake is pressed would indicate to me a starter issue.