2006 X type won't start
If you now for sure the battery is good you have a bad starter or connections going to starter. Check connections at starter making sure they are clean and tight.
Remove the battery cables and clean the terminals and the cable ends. Use heaping tablespoon of Baking Soda with a glass of water and pour over the corrosion on battery. Check other end of cables and be sure the connections are tight and will no move. Reinstall battery cables and try again.
Those Jaguars have many, many problems- I'm surprised there are any that DO start- or shift- get rid of it-
Looking for a Used X-TYPE in your area?
CarGurus has 575 nationwide X-TYPE listings starting at $1,600.
Search Jaguar X-TYPE Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Jaguar X-TYPE Experts