As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT BEGINNING OF TAKE OFF ROLL, CENTER HYDRAULIC SYSTEM PRESSURE LOW MESSAGE APPEARED ON EICAS. RETURNED TO GATE. ASSIGNED MEL 29-31-2-01. REMOVED AND REPLACED CENTER HYDRAULIC SYSTEM PRESSURE SWITCH IAW THE M/M. GROUND CHECKED GOOD AND CLEARED MEL.