As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ON DEPARTURE FLIGHT ATTENDANT REPORTED SMELL OF SMOKE COMING FROM THE LAVATORY AND THE LAVATORY SMOKE DETECTOR WAS GOING OFF. FLIGHT RETURNED. ALL LIGHTS, WIRING, PUMP AND WASTE RECEPTACLE CHECKED, NO FAULT. REPLACED LAVATORY PUMP MOTOR.