As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX FLIGHT NR 2244: AFTER ENGINE START AT PUSHBACK, NOTED NR 2 RUD HYD CAUTION LIGHT STAYED ILLUMINATED. AIRCRAFT RETURNED TO BLOCK. MAINTENANCE REFERENCED SERVICE LETTER DH8-400-SL-007B AND DETERMINED TO BE A NUISANCE FAULT. POWERED A/C DOWN AND UP. GROUND RAN NR 2 ENGINE PER SAME SERVICE LETTER. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.