The engine P0818 Code comes when the car engine is found. You need to solve the car engine if you want to run the car safely. The deactivation process of cylinders is realized by releasing a synchronizer pin that normally interlocks the cam follower and rocker arms. P0818 code resolves the synchronizer pin is released using hydraulic compression which is measured by a dedicated solenoid. The engine P0818 engine code seems a kind of powertrain problem and this problem can be fixed easily. Do not worry about the problem. The problem can be fixed easily without changing any component or removing any part.