As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING GND PRESSURIZATION, SMOKE AFT LAVATORY, WARNING GENERATED ON EICAS. RECEIVED AURAL WARNING FROM SMOKE DETECTOR IN LAVATORY. PERFORMED OPERATIONS TEST OF AFT LAVATORY SMOKE DETECTOR IAW AMM 26-16-00-710-801, NO DEFECTS NOTED. RAN HEATING & COOLING PACKS FOR EXTENDED PERIOD OF TIME & RE-PRESSURIZED ACFT IAW AMM 21-31-00-910-801. COULD NOT DUPLICATE EICAS & AUDIO WARNINGS FROM AFT LAVATORY SMOKE DETECTOR. NO FAULT FOUND.