As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GEAR WOULD NOT RETRACT. BOTH GEAR POSITION INDICTORS SHOWED 3 GREEN TRIANGLES AND 3 RED UNLOCKS. RETURNED HANDLE TO DOWN POSITION AND HAD ECAM STATUS MESSAGE OF L/G RETRACTION INOP, TRIED BOTH L/G POSITION DETECTION SYS 1 AND 2. REMOVED AND REPLACED LANDING GEAR CONTROL UNIT PER AIRBUS MM REF 32-31-11-4. SYSTEM OPS CK OK.