As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW HAD MASTER WARNING LIGHT/BELLY DOOR LIGHT AT 90 KNOTS. CREW REJECTED TAKEOFF AND RETURNED TO BLOCKS. MAINTENANCE COMPLIED WITH REJECTED TAKEOFF INSPECTION AND NO DEFECTS WERE NOTED. MAINTENANCE THEN INSPECTED BELLY DOORS AND FOUND THE -B- PIT DOOR AJAR. THE DOOR WAS CYCLED AND BELLY DOOR LIGHTS SYTEMS TESTED NORMAL PER ALL APPLICABLE MANUALS. AIRCRAFT WAS RETURNED TO SERVICE.