The engine P0978 Code lets you know about the car engine problem and it is important thing for solving the car engine problem. The engine should be fixed properly and follow the right way for solving the car engine. The deactivation process of cylinders is realized by releasing a synchronizer pin that generally links the cam follower and rocker arms. The engine P0978 code determinations the synchronizer pin is released using hydraulic heaviness which is measured by a devoted solenoid. If you cannot fix the car engine, you must not try to fix it. You must rely on the automobile engineer to fix it.