As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE GROUND SHIFT SWITCH FAILED TO MOVE TO THE FLIGHT MODE AFTER TAKEOFF. THE GEAR HANDLE WOULD NOT RAISE. THE AIRCRAFT WAS RETURNED TO LAX WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND BOLT BACKED OUT OF NOSE GEAR OLEO SWITCH. REPLACED HARDWARE IAW IPC 32-60-00, FIGURE 1A AND OPERATION CHECKED GOOD.