United States 89V121000
General Motors, LLC
The problem
THE REAR AXLE RELAY VALVES (ONE PER AXLE) MAY NOT MEET BRAKE RELEASE TIMING REQUIREMENTS OF FMVSS 121.
Risk
THE REAR AXLE BRAKES MAY NOT RELEASE IN THE TIMESSPECIFIED BY FMVSS 121.
What owners should do
REPLACE THE NONCOMPLYING RELAY VALVES.
Units 7