At a glance
What can fail
Brake fluid may react with internal coatings in the brake control unit, causing a valve to stick open. This can increase brake pedal travel and stopping distance.
What the fix does
Dealers will flush the brake system with DOT 4 fluid, test the brake control unit, and replace it if a stuck valve is found.
Summarized — see the official notice for exact wording, dates, and contacts.