What was found
RUDDER RATIO EICAS MSG & DISCRETE LIGHT CAME ON TAXI OUT AC RETURNED TO GATE AND MAINTENANCE GROUNDED AC . MAINTENANCE DEFERRED RUDDER RATIO SYSTEM . IAW ABX-MEL -27-21-1. AND REMOVED/REPLACED CSEU M538 1 RIGHT, PERFORMED RUDDER RATIO OPS OK PER AMM 27-21-00. DI 51456 CONTINUE OPEN PART EFF VERIFIED. NEXT NEXT LEG ACCOMPLISHED RUDDER RATIO BITE IAW FIM 27-09. FT 814. MODULE FAULT WAS SET ON RIGHT MODULE, FULT CLEARED. ACCOMPLISHED TEST MULTIPLE TIME, NO FAULTS NOTED. THIS ACTION CLOSES DI, PLACARD REMOVED. NO MEL RE-ACTIVATION APPLIED.