What was found
AIRCRAFT WAS GROUNDED: AFTER TAKEOFF, LANDING GEAR WOULD NOT RETRACT. L/G CTL MESSAGE ON GEAR PAGE IN AMBER. PRIOR TO PUSHBACK, LGCIU 1 FAULT BUT WA SCLEARED WITH MAINTENANCE AND BYTE TESTED OK. RETUIRNED TO FIELD EMEREGNCY DECLARE. AIRCRAFT LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED PILOT VALVE ON LANDING GEAR SAFET VALVE IAW AMM 32-31-17.