As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAV SMOKE WARNING MESSAGE APPEARED DURING PASSENGER BOARDING. NO SMOKE WAS EVIDENT. REMOVED FROM SERVICE. PERFORMED OPERATIONS TEST OF FWD LAV SMOKE DETECTOR, IAW E-175 AMM TASK 26-14-01-700-801-A. OPERATIONS TEST PASSED, NO FURTHER DEFECTS. CREW STATED FWD LAV ALARM WARNING CAME ON DURING PASSENGER BOARDING, AFT LAV NO DEFECTS FOUND. COULD NOT DUPLICATE. RETURNED TO SERVICE. NO PARTS REPLACED.