As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
"CHECK FIRE DET" WARNING CAME ON AT THE START OF THE TAKEOFF ROLL AND WAWS INTERMITTENT AFTER THAT. ABORTED TAKEOFF AND RETURNED TO THE GATE. FOUND CBK7 OPEN, RESET CB AND PERFORMED OPERATIONAL CHECK OF THE SYSTEM IAW AMM 26-11-100-710-801. CHECKS GOOD. NO DEFECTS. RETURNED TO SERVICE.