As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 2615, THE CREW REPORTED AN ELECTRICAL BURNING ODOR IN THE AIRCRAFT DURING TAXI. CONTRACT MAINTENANCE INSPECTED THE AIRCRAFT AND DETERMINED THE ODOR TO BE COMING FROM THE APU. MAINTENANCE SUBSEQUENTLY REMOVED AND REPLACED THE APU SHUNT, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE AIRCRATF WAS APPROVED FOR RETURN TO SERVICE.