What was found
AT FL350, MASTER WARNING, AURAL ALARM, AND CABIN ALTITUDE. CABIN ALTITUDE 10, 000, CABIN ALTITUDE ON AUTO 2 WAS NOT RESPONDING IN MANAUL OR AUTO 1. CREW INITIATED DIVERSION. CREW DECLARED. LANDED WITHOUT INCIDENT. POST FLIGHT WALK AROUND WAS NORMAL. AIRCRAFT WAS GROUNDED FOR INSPECTION AND MAINTENANCE. IAW B767 FIM 21-31 FAULT TREE 803 NO FAULTS NOTED. OPERATIONAL AND EXTERIOR INSPECTION OF OUTFLOW VALVE IAW B767 AMM 21-31-04 NOTED NO FAULTS. OVERBOARD EXHAUST VALVE CHECK GOOD IAW B767 AMM 21-58-05. REMOVED AND REPLACED CABIN ALTITUDE AUTO PRESSURE CONTROLLER IAW B767 AMM 21-31-02. PRESSURE LEAK CHECK NOTED NO FAULTS IAW B767 AMM 05-51-4. OPERATIONAL CHECK GOOD.