At a glance
What can fail
The rear shoulder belt may not retract properly because the spring inside the retractor has come loose from its spool. In a crash, slack in the belt could increase injury severity.
What the fix does
Dealers will inspect both rear shoulder belt retractors, install a spring cover retaining strap to each one, and replace any retractor that doesn't work correctly.
Summarized — see the official notice for exact wording, dates, and contacts.