As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 2930 LT AIR VALVE CAME ON INFLIGHT, LIGHT WENT OUT BELOW 92 PERCENT NG. AIR RETURN TO DTW. MAINTENANCE REMOVED AND REPLACED LT GARRET VALVE P/N 5056T88P01, SN/ON AEX10142. ALL CHECKS OF LT AIR VALVE SYSTEM ARE GOOD AT THIS TIME.