As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDX - ON FLIGHT 2512, RETURNED TO GATE, ON TAXI FOR DEPARTURE, NR 2 FUEL FILTER BYPASS CAUTION LIGHT ILLUMINATED. NO ABNOMAL FUEL FLOW NOTED. MAINTENANCE REMOVED AND REPLACED FUEL CONTROL UNIT. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.