The B2591 Code clarifies the engine problem and the problem is found on the body of the car engine. It is very calm to solve the problem with the engine according to the genuine meaning by the automobile engineer. You should not use the dictionary meaning of the engine code for solving the car engine problem. The dictionary meaning is not cooperative and it is not used for solving the car engine. You will get the general/dictionary meaning online. In this case, you can use Google search engine for solving the car engine problem. Do not drive the car until the problem of the engine is fixed.