The automobile meaning of the engine U1144 Code is found online but it is not important at all. You cannot use this meaning without understanding for solving the car engine problem. The right meaning of the code is in the car engine manual what is necessary to follow. If wrong meaning from different car manufacturer is followed, the car engine problem will not be solved and new problems may come in the car engine. Deactivation of cylinders is realized by releasing a synchronizer pin that usually interlocks the cam follower and rocker arms. The engine U1153 code determinations the synchronizer pin is released using hydraulic compression which is precise by a dedicated solenoid.