What was found
STEERING INOP MASTER CAUTION IN FLIGHT. QRH COMPLETE. NORMAL LANDING, HOWEVER, STEERING COULD NOT BE REESTABLISHED AFTERWARD REQUIRING TOW TO GATE. (FLIGHT 3877 - FILED CLOSED)INTERROGATED A/C MDC PER AMM 45-45-00. RETRIEVED SEVERAL B1 CODES. B1 007456 NWS ECU. CODE 007467 STEERING ACT. CODE 007725 RUDDER PEDAL RVDT. CODE 006931 HANDWHEEL. ALL OCCURRING ON 11SEP2023 @ 1025SUSPECTED INTERNAL FAULT OF ECU. TROUBLESHOT PER FIM 32-51-10. REMOVED AND REPLACED NWS ECU PER AMM 32-51-10. RIGGING OF THE RVDT WAS ACCOMPLISHED WITH A/C ON GROUND PER AMM 32-51-05. RVDT POSITION TOLERANT WITHIN 0.0+ OR - 1.00 DEGREE. AUTORIGGING DISPLAY PASSED ON MFD UPON ELECTRICAL RIGGING FINAL TEST . REF AMM 32-51-05. NO RELATED FAULT.