As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT NR 2735 FROM LOG PAGE: OXYGEN LIGHT ILLUM. GAUGE IND 750 PSI, 1700 PSI AT ACCEPTANCE OF AIRCRAFT. AIR RETURN TO DTW. MAINTENANCE REMOVED AND REPLACED LT AND RT AFT OXYGEN CYLINDERS (DUE TO LEAKING AT ON/OFF SELECTOR) & REPLACED BROKEN PRESSURE INDICATING CAPILLARY LINE. LEAK CHECKS GOOD.