At a glance
What can fail
The radiator fan motor shaft may seize and stop working, or the lock nut holding the fan blade to the motor may loosen, causing the fan hub to slip on the shaft. A loose hub can make the belt pulley run off-center, causing the fan belt to slip or break. Either condition can lead to engine overheating and stalling.
What the fix does
The complete cooling fan assembly will be replaced, or a new fan blade with a new lock nut will be installed.
Summarized — see the official notice for exact wording, dates, and contacts.