As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5531, SDF TO IAH - DURING CRUISE, THE FLIGHT CREW RECEIVED A STEERING INOP CAUTION MESSAGE ON EICAS. THE CREW FOLLOWED THE QRH CHECKLISTS BUT THE MESSAGE REMAINED. THE AIRCRAFT LANDED AT SDF WITHOUT INCIDENT AND WAS TOWED TO THE GATE. DURING TROUBLESHOOTING MAINTENANCE SLAVED IN A TILLER, ECU AND SERVO ALL NO FIX. THE PSEU FAULT CODES POINTED TO RVDT FAILURES, AND BOTH RVDT'S WERE ADJUSTED AND THE STEERING SYSTEM OPS CHECKED GOOD.