As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, R BLD ISLN VAL EICAS MESSAGE. R ISLN VAL DISCRETE LIGHT. CREW RETURNED TO THE GATE (BTB). MTX TROUBLE SHOT AND REMOVED AND REPLACED RH BLEED ISOLATION VALVE IAW B767 AMM 36-11-04. LEAKS AND OPS CHECK GOOD. AIRCRAFT REMAINS NO ETOPS. RETURNED A/C TO SERVICE.