As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENROUTE, CRUISING AT 7000 FT, A SGL CH LIGHT ILLUMINATED ON THE NR 2 ENGINE. AIRCRAFT RETURNED TO DEPARTURE. NO EMERGENCY DECLARED. LANDED WITHOUT FURTHER INCIDENT. MAINTENANCE ADJUSTED THE GAP OF DUAL COIL MAGNETIC SENSORS. OPS CHECKED GOOD. OCF FLIGHT SUCCESSFUL.