As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING T/C 05-020-01, FOUND PRESENT LEG FAULT MAINTENANCE MESSAGE 73-44632 FAN SPEED (N1) SENSOR LOW TOOTH SIGNAL IS INVALID. DETECTED BY ENG 1 EEC CHANNEL-B FAULT IS NOT ACTIVE AND UNCORRELATED. GROUNDED - YES. MAINTENANCE MESSAGE IS UNCORRELATED AND FAULT IS NOT ACTIVE AT THIS TIME A/C IS ACCEPTABLE FOR DISPATCH REF 737-9 IFIM GENERAL INFO AND STANDARD FAULT ISOLATION PRACTICES STEP 3 A (1) (C).