car?

i have a1997 xantia19 td the alarm will not respond two key phob two switch, blade type its been tested good strong signal not the transponder type its imobilised by a key pad linked to fuel solonoid top button locks car bottom button dead locks doors and arms alarm,but alarm works if you disconnect then reconect battery open door,alarm goes off to stop,have to reset with button on dash ,dont know how to reprogram key phob any answers with thanks!!!