As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER APU START AT DEPARTURE WITH PACKS ON FOR SEVERAL MINUTES FLT CREW NOTED ELECTRICAL ODOR THROUGHOUT CABIN AND FLIGHT DECK. MAINTENANCE RAN PACKS USING APU PNEUMATICS FOR 20 MINS IN ACCORDANCE WITH MM21-00-01 WITH NO FURTHER SMELL NOTED. RETURNED AIRCRAFT TO SERVICE.