The general meaning of the engine P1642 Code gives very general information of the car engine problem and these information may match with your car engine problem. That is why, you should take the car to automobile repair center to check the car engine and solve the problem. The engine code is related with the area of the car engine problem and you must get the meaning of the code from the car manufacturer. However, it becomes easier to solve the car engine problem if you take the car to expert to automobile engineer. It may be cheap to fix the problem.