As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IT WAS REPORTED AFTER APU SHUTDOWN FLAMES WERE COMING FROM APU EXHAUST AREA. WHEN POWER WAS SWITCHED OFF FLAMES EXTINGUISHED. MAINTENANCE TROUBLESHOT, INSPECTED, REMOVED AND REPLACED THE APU FUEL SELONOID VALVE AFTER INSPECTING FOR FIRE DAMAGE. NO DAMAGE NOTED. USING THE AIRCRAFT MANUALS. CHECKS WERE ACCOMPLISHED USING AIRCRAFT MANUALS AND AIRCRAFT RELEASED FOR SERVICE.