As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EFIS COMPUTER MONITOR HEADING CAUTION MESSAGE AT 10 KNOTS ON TAKEOFF ROLL. REJECTED TAKEOFF. PERFORMED FUNCTIONAL TEST OF THE AHARS IAW AMM 34-21-00 AND FUNCTIONAL TEST OF THE ATTITUDE AND HEADING COMPUTER IAW AMM 34-21-01. EFIS COMPUTER MONITOR MESSAGE FOUND TO BE CAUSED BY KNOWN ENVIRONMENTAL CONDITIONS. (REF LOG PAGE 651176, DISC #2 REGARDING REJECTED TAKE OFF.)