As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT, THE NR 1 ENIGNE OIL FILTER MESSAGE WAS DISPLAYED. THE NR 1 ENGINE WAS SHUT DOWN AND THE AIRCRAFT RETURNED TO THE GATE. MAINTENANCE INSPECTED THE OIL FILTER AND FOUND NO CONTAMINATION. DIFFERENTIAL PRESSURE SWITCH WAS REMOVED AND REPLACED.