Mike your back up battery needs replacing and your XM panel needs re-booting by removing all power to it and then powering back up again.Be aware that mains voltage is supplied to the control panel so make sure,if you do it yourself,that you switch off the mains supply first before fitting a new battery.When the new battery has been fitted and control panel is securely closed then switch on the mains supply to it again.
The panel has now been re-booted and you will probably need to enter your code then press reset.
CTC, November 2008