As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW WAS RE-POSITIONING N233MW FROM KSBA TO KCRQ. DURING THE TAKE-OFF PHASE, THE CREW NOTICED A FLASHING MASTER CAUTION WARNING AND THE R EFC OFF ANNUNCIATIOR ILLUMINATED. CREW DECIDED TO ABORT THE TAKE-OFF. AFTER EXITING THE RUNWAY, CREW PROCEEDED TO RE-TEST THE EFC CHECK & THIS TIME THE TEST PASSED & THE CREW COMPLETED THE RE-POSITIONING FLIGHT WAS WITHOUT ANY PROBLEMS.