What was found
FLT 437, BOS-MCO, CABIN ALTITUDE CLIMBING AS LEVELING OFF AT ALT. STARTED DESCENT AND GOT CABIN ALT HI WARNING. KEPT DESCENDING TO 20,000 FT AND CABIN ALT STABILIZED. DIVERTED TO JFK. MAX CABIN ALT 9800 FT. TROUBLESHOT PER FIM 21-31-00-810-806-A00. FAULT CODE 2111008CPC. REMOVED AND REPLACED CPCS CONTROLLER FROM FWD AVIONICS IAW 21-31-01. OPS CHECK GOOD, NO FAULTS NOTED. A/C OK FOR SERVICE.