The car engine P0078 Code is found in all car engine and manufacturers set the code meaning. You will get different meanings from different car manufacturers of the same code. You should be careful when you select the car engine code meaning. Do not use automobile meaning of the code for solving the car engine. It makes terrible problem in the car engine if wrong meaning of the code is used. For solving the car engine, some tools are necessary to use. You should not drive the car with any car engine problem. After solving the car engine, take the car for a test drive.