What was found
ON DEPARTURE OUT OF DCA WHILE RETRACTING THE FLAPS FROM 2 TO 1, RECEIVED SLAT FAIL MESSAGE. SLATS INDICATED AMBER 3 AND FLAPS WERE INDICATED GREEN DASHES. COMPLIED WITH QRH, DIVERTED TO IAD. NO EMERGENCY DECLARED. LANDED WITHOUT INCIDENT. MAINTENANCE CLEARED THE SF-ACE INHIBITS AND PERFORMED OPS CHECKS OF THE SLAT/FLAP SYSTEM IAW EMB 175 FIM 27-81-00-810-807. MAINTENANCE LATER REMOVED AND REPLACED BOTH RT OUTBOARD SLAT SKEW SENSORS AND THEN COMPLIED WITH SI 278065 TO REPLACE THE RT SLAT 3/4 HARNESS.