As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT NOT GROUNDED: FIRE WARNING LIGHTS ON BOTH SIDES ILLUMINATE ON MASTER CAUTION RECALL AND WHEN WHEN FUEL MASTER CAUTION IS ILLUMINATED. ACCOMPLISHED ENGINE RUN FOR BOTH ENGINES NO FAULTS NOTED. ACCOMPLISHED ENGINE/APU FIRE DETECTION CONTROL MODULE BITE TEST IAW AMM 26-10-00 NO FAULTS NOTED.