As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED APU GENERATOR OFF BUS MESSAGE AFTER PUSHBACK DURING NR 2 ENGINE START ACCOMPANIED BY FAINT ACRID SCENT. MAINTENANCE INSPECTED AND PERFORMED ENGINE RUNS ON NR 1 AND NR 2 ENGINE AND APU. PERFORMED DECONTAMINATION OF AIR CONDITIONING SYSTEM AND NO FURTHER SMELL WAS NOTED.