As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, THE NR 1 ENGINE TREND DATA SHOWS OIL PRESSURE TO BE LOWER THAN EXPECTED, INDICATION ERRORS ARE SUSPECT. GROUNDED - YES. REMOVED AND REPLACED THE OIL PRESSURE SENSOR FROM THE NR 1 ENGINE IAW AMM 79-32-01, OPS AND OIL CHECKED GOOD.