What was found
DURING TAXI WITH BOTH ENGINES RUNNING AND ENGINE ANTI-ICE SELECTED ON WE OBSERVED THE RIGHT ENGINE ANTI-ICE VALVE LIGHT ILLUMINATED AND A RIGHT ENGINE ANTI-ICE AMBER MESSAGE AC RETURNED TO GATE( BTB) AND MTX GROUND AC . TROUBLESHOT AND FOUND MX PROCEDURES FOR MEL 36-11-8-1-1A-1 NOT C/W CORRECTLY (PRV WAS LOCKED CLOSED, HPSOV NOT LOCKED, OVERPRESSURE SWITCH NOT DISCONNECTED CAPPED AND STOWED) APPLIED/REAPPLIED DEACTIVATION PROCEDURES PER ABX MPM 36-11-8-1-1A-1. OPS CHECK GOOD. DI REMAINS OPEN. A/C REMAINS NO ETOPS..MTX RETURNED AC TO SERVICE