As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FLIGHT 4585 PRIOR TO PUSHBACK THE AFT LAVATORY SMOKE MESSAGE CAME ON, THEN SMOKE FILED THE COCKPIT. THE AIRCRAFT RETURNED TO THE GATE. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE LEFT AND RIGHT BLEED AIR TEMP SENSORS IAW CRJ AMM 36-21-19. LEFT AND RIGHT PART NUMBER REMOVED GG670-800053. LEFT SERIAL NUMBER OFF 05006. RIGHT SERIAL NUMBER OFF 05779. THE OPERATIONAL CHECK WAS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.