As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON AIR EXCHANGE FROM APU TO ENGINE, HEARD A POP AND SMELLED AN ODOR WHICH DISSIPATED IMMEDIATELY. LIMITED AIR FLOW BOTH PACKS ON APU. LT PACK TEMP INCREASES ON APU. INSPECTED APU DUCTS & BOTH PACKS IN AFT EQUIPMENT BAY. RAN PACKS & NOTICED ODOR FROM LT PACK. RT PACK OPS CHECKED GOOD. R & R ACM WATER SEPARATOR & PRSOV. OPS CHECKED GOOD.