NHTSA Complaint #11373629 — 2014 BMW M5

BEHAVIOR OF MY CAR'S DCT TRANSMISSION HAS CREATED A DANGEROUS SITUATION WHICH ALMOST RESULTED IN AN ACCIDENT FOR ME. I BELIEVE THIS IS DUE TO A SOFTWARE CHANGE BMW MADE TO THE DCT TRANSMISSION. THE ISSUE IS AS FOLLOWS: -WHEN DRIVING AT HIGHWAY SPEED, WHEN YOU RELEASE THE THROTTLE AND LET THE VEHICLE COAST (AS WHEN YOU WANT THE VEHICLE TO NATURALLY DECELERATE WITHOUT BRAKING) THE TRANSMISSION WILL DISENGAGE THE DCT CLUTCHES. THE CAR WILL THEN MAINTAIN SPEED (AS IF CRUISE CONTROL WERE ENGAGED) INSTEAD OF NATURALLY DECELERATING. IN AND OF ITSELF, THIS BEHAVIOR IS DANGEROUS DUE TO THE FACT THE VEHICLE WILL MAINTAIN UNWANTED SPEED. -WHEN THEN TRYING TO RE-ACCELERATE QUICKLY FROM COASTING WHERE A DOWNSHIFT IS NEEDED (AS IN WHEN NEEDING TO PASS LEGALLY ON A 2 LANE HIGHWAY), THE CAR WILL NOT RE-ENGAGE THE CLUTCHES FOR A COUPLE OF SECONDS OR SO. THIS CAUSES TOTAL LOSS OF POWER OR ACCELERATION FOR 2 OR SO SECONDS. WHILE THIS MAY SEEM LIKE A RELATIVELY MINOR SITUATION, THE ABOVE SITUATION ALMOST CAUSED A SERIOUS ACCIDENT AT HIGHWAY SPEED. ALSO, MY CAR DID NOT PREVIOUSLY DISPLAY THIS BEHAVIOR UNTIL AFTER A SERVICE VISIT (I BELIEVE LAST YEAR). I SUSPECT THE DCT TRANSMISSION SOFTWARE WAS UPDATED BY BMW WITHOUT MY KNOWLEDGE AND IS THE SOURCE OF THIS CHANGE IN VEHICLE BEHAVIOR.