As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AIR CONDITIONING PACK OPERATION ON THE GROUND, LEFT AIR CONDITIONING PACK INDICATED A PACK TRIP AND DUCT OVERHEAT AT PACK START UP. INDICATION FOR THE DUCT TEMPERATURE DID NOT SHOW A DUCT OVERHEAT. DETERMINED THIS TO BE AN INDICATION PROBLEM USING THE FIM. REPLACED THE AIR CONDITIONING ACCESSORY UNIT AND OPERATIONAL CHECK WAS NORMAL.