The B1252 Code has multiple meanings that is connected with the model and manufacturer. It seems that the problem is related with the body. The meaning of the code can be different and here we will discuss about one problem of the code. Deactivation of cylinders is completed by discharging a synchronizer pin that usually interlocks the cam follower and rocker arms. B1252 code resolutions the synchronizer pin is free using hydraulic pressure that is controlled by a devoted solenoid. You need to fix the problem by the professional. If you do not do so, you may face several problems.