As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT DUCT LEAK LIGHT CAME ON INFLIGHT. LIGHT EXTINGUISHED AFTER TWO AND ONE HALF MINUTES. RETURNED TO LAX. FOUND LEFT DEICE PRESSURE REGULATOR LEAKING. REMOVED AND REPLACED IT WITH A SERVICEABLE PART. OPS CHECKS GOOD. PERFORMED ENGINE RUNS AT TAKEOFF AND CLIMB POWER WITH BLEEDS ON AND NO DUCT LEAK LIGHTS CAME ON. OPS CHECKS GOOD. (P/N 38E96-6A) (S/N B-2390)