As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: MASTER CAUTION ILLUMINATED ALONG WITH AN "ANTI ICE" ANNUNCIATION ON SIX PACK DURING TAKEOFF ROLL. REJECTED TAKEOFF AT APPROXIMATELY 20 KTS AND RETURNED TO GATE. REPLACED RH ENGINE ANTI-ICE VALVE IAW 737 FIM 30-21-00-810-805, LEAK AND OPS CHECK GOOD.