As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI CREW REPORTED THE NR 3 HYDRAULIC CAUTION LIGHT ILLUMINATED. FLIGHT RETURNED TO THE GATE FOR MX. CONTRACT MX CHECKED THE NR 3 ACCUMULATORS AND THE RESERVOIR BOTH ARE SHOWING IN THE GREEN. RECYCLED DCMP C/B AND DRAINED RESIDUAL PRESSURE FROM NR 3 SYSTEM. CREW RAN NR 3 SYSTEM AND CYCLED ELEVATORS, ALL OP'S CHECKED GOOD.