The car engine should be fixed by the professional and in this case the engine P0401 Code helps for solving the car engine problem. During the car engine is tested, the engine code is screened. Do not drive the car with the car engine problem. The engine code is necessary thing for fixing the car engine. If the right meaning of the code is not found, you cannot fix the car engine properly. You need to study more and more if you want to learn about the car engine. Some tools are used for solving the car engine problem. If you do not know the process of solving the car engine, you should hand over the car to professional.