As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 3341 - IN CRUISE FLIGHT, THE NR 1 ENGINE HYDRAULIC PUMP CAUTION LIGHT ILLUMINATED. THE CREW PERFORMED QUICK REFERENCE PROCEDURES AND CONTINUED TO DTW. MAINTENANCE REPLACED THE NR 1 ENGINE DRIVEN HYDRAULIC PUMP. SYSTEM OPERATED SATISFACTORILY. (X)