As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) FLIGHT CREW NOTICED DURING DESCENT AFTER STARTING THE APU AND BLEED TRANSFERRED TO APU, A FUEL SMELL IN THE COCKPIT VIA AIR CONDITIONING PACK. APU SHUT DOWN. INITIAL INSPECTION DID NOT LOCATE ANY EXTERNAL LEAK (REQUIRES INVESTIGATION TO THE INTERNAL APU COMPONENTS). APU DEFERRED.