As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT NR 2176 DURING ENGINE START BOTH LEFT AND RIGHT TRU CAUTION LIGHTS WEREN'T ILLUMINATED. AFTER DISCONNECTING EXTERNAL POWER BOTH LIGHTS CAME ON. HOWEVER, NR 2 DC GENERATOR LIGHT ON. RESET VIA CHECKLIST HOWEVER, EVENT REOCCURRED. MAINTENANCE REPLACED NR 2 GCU AND GENERATOR. OPERATIONAL CHECK GOOD. NO FURTHER DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.