As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PERFORMED AN ABORTED APPROACH DUE TO AN ABNORMAL NOSE GEAR INDICATION WITH GEAR HANDLE DOWN. RAN QRH AND DECLARED EMERGENCY. HAD AN UNEVENTFUL LANDING AND TAXI TO GATE. MAINTENANCE REMOVED AND REPLACED THE NOSE GEAR DOWN SWITCH S1-412 IAW MM. OPERATION AND GEAR SWING CHECKS OK.