NHTSA (USA)Critical
1993 PORSCHE 911NHTSA Campaign #93V205000
The official notice
Defect
THE HYDRAULIC BRAKE PRESSURE REDUCTION VALVE CAUSES THE RATE OF HYDRAULIC PRESSURE REDUCTION TO SLOW DOWN, WHICH MAY RESULT IN THE REAR WHEELS LOCKING-UP EVEN WITH THE ANTI-LOCK BRAKE SYSTEM IN OPERATION.
Safety Risk
REAR WHEEL LOCK-UP MAY RESULT IN LOSS OF VEHICLECONTROL AND AN ACCIDENT.
Remedy
PORSCHE DEALERS WILL INSTALL A MODIFIED HYDRAULIC BRAKE PRESSURE REDUCTION VALVE.
Updated June 10, 2026