2004 xtype jaguar key fob suddenly stopped working car locked and alarmed if i use key in the door will the alarm go off if so how do i stop it

Your key fob needs reprogramming, and yes the alarm will go off when you open the door, but you have enough time to put the key in the ignition which will prevent the alarm sounding. Car is usable until you get the fob sorted by locking and unlocking using the key.

Jaguar X-Type Programming (Pairing) a Remote KeyFob X-Type 2.0, 2.5 and 3.0L


Programming or pairing a new remote Keyfob for the X Type is a very simple job that will cost a substantial amount if it is done by Jaguar. It's annoying but this may need to be done if your Keyfob battery has been allowed to go flat, or the car battery has been removed for any length of time.
Follow these steps exactly and you should have no problems, pairing old or replacement Keyfobs for your car.

1.)I would recommended that you ensure all key fobs are fitted with new batteries. ( Click here to see battery replacement guide).
2.)Get in the car and close the drivers side door.
3.)Put the key into the ignition and turn to position I.
4.)Wait 5 seconds
5.)Turn the key quickly to position II then back to I four times.
6.)You should hear a single chime.
7.)Remove the Key
8.)For each Keyfob in rapid succesion. Press any single button on the keyfob you wish to pair, you should hear a chime as each Keyfob is paired with the security system. After the chime do the next Keyfob.
9.)Check operation of each Keyfob.

Take it apart and clean the contacts and try your key aswell change the battery