As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFT LT LAV SMOKE DETECTOR CHIRPING AT GATE. FOUND AFT LT LAV WATER HEATER OVERHEATING. FWD ITEM TO NEF 381.043 FOR REPLACEMENT-ALSO DETERMINED EXTERNAL START CART CONTRIBUTING FUMES INTO THE CABIN. REMOVED START CART (14138)-NO FURTHER ISSUES.