What was found
REPEAT DISCREPANCY - DURING CLIMBOUT IN THE FLIGHT LEVELS AND NEAR LEVEL OFF, THE AMBER FIRE BOTTLE LOW 2 CAS MESSAGE DISPLAYED AND REMAINED ON FOR ENTIRE CRUISE PORTION. MESSAGE EXTINGUISHED EVENTUALLY DURING DESCENT AND DIVERSION FOR MX. CORRECTIVE ACTION: REMOVED SUSPECTED LOW PSI FIRE EXTINGUISHER 2 (AFT) P/N: 30400037-1 S/N: 97493B1, AND INSTALLED AN OVERHAULED FIRE EXTINGUISHER P/N: 30400037-1 S/N: 55042B1. PERFORMED ALL FOLLOW ON CHECKS. NO DEFECTS NOTED. WORK DONE IAW CE-560XL ASCEND AMM 26-21-01.