What was found
AFTER LANDING WITH STEERING SYSTEM ENGAGED AT END RUNWAY CREW COULD TURN PLANE ONTO TAXI WAY NOTIFY TOWER THEY WERE HAVING PROBLEM WITH TURNING (STEERING) AIRCRAFT. CREW DISENGAGED STEERING SYSTEM AND USED DIFFERENTIAL BRAKING AND ENGINE POWER TO TURN AND TAXI AIRCRAFT OFF RUNWAY TO FBO AT THE AIRPORT. FLIGHT CREW NOTIFIED MAINTENANCE OF PROBLEM, MAINTENANCE HAD THEM MEL THE STEERING SYSTEM, PER THERE APPROVED MEL 32-3 AND HAVE THEM FOLLOW FLIGHT MANUAL LIMITATIONS AND PERFORMANCE INFORMATION WITH NOSE WHEEL STEERING INOPERATIVE. WHEN AIRCRAFT RETURN TO HOME BASE MAINTENANCE TROUBLESHOOT THE STEERING SYSTEM AND FOUND STEERING COMPUTER CAUSE THE PROBLEM.