The engine C1891 Code is a notification of the engine problem and if the real meaning of the engine code is not found, do not use other meanings of the engine code for solving the car engine problem. You will find various meanings of the same engine code but when you look for the original meaning of the code, the meaning of the code is related with the car brand or car manufacturer. Do not use automobile meaning of the engine code. The automobile meaning of the code is not helpful. You will get only general information of the code from the automobile meaning.