As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DEN ON FLIGHT 2443 ABORTED TAKEOFF DUE TO LEFT REVERSE UNSAFE CAUTION MESSAGE CAME ON AT THE BEGINING OF THE TAKEOFF ROLL. COMPLIED WITH FUNCTIONAL TEST OF LEFT REVERSER IAW 78-30-00-720-801. NO PARTS REPLACED. OPERATIONAL CHECKS GOOD. AIRCRAFT RETURNED TO SERVICE.