As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI, SHUTDOWN THE NR 1 ENGINE FOR FLOW TIME. RESTARTED USING CROSSBLEED PROCEEDURES. LINED UP ON RUNWAY AND THE NR 2 ENGINE FILTER BYPASS LIGHT ILLUMINATED FOR APPROXIMATELY 1 MINUTE THEN EXTINGUISHED. ACFT GROUNDED. REPLACED THE NR ENGINE FUEL FILTER DIFFERENTIAL PRESSURE SWITCH IAW FIM 73-05, TASK 801. AMM 73-34-01-000-801-F00, & 73-34-01-400-801-F00. OPS CHECKED OK. PERFORMED IDLE POWER LEAK CHECK IAW AMM 71-00-00-700-801-F00 & EEC TEST IAW AMM 73-21-00-700-804F00. OPS & LEAK CHECKED OK.