As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IMMEDIATELY AFTER T/O AS RETRACTING WHEELS, MASTER WARNING, MAP DUCT LEAK, AIR CONDITIONING PANEL DUCT LEAK. RETURNED TO LAX. SHUT DOWN LEFT ENGINE ON TAXI WAY. LIGHT OUT ON ENGINE SHUTDOWN. REPLACED LEFT ENGINE PRESSURE REGULATOR IAW MM EMB 30-10-06. OPERATIONAL CHECK GOOD.