As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CMH - FLT 4975 - LAVATORY SMOKE INDICATION CAME ON DURING TRANSITION FROM APU BLEED TO ENGINE BLEED. POSSIBLE ENGINE OIL LEAK. MAINTENANCE REMOVED AND REPLACED THE NR 2 ENGINE IAW EMB MM. OPS AND LEAK CHECKS WERE GOOD AND AIRCRAFT WAS RETURNED TO SERVICE. (M)