You need to know about the car engine problem and that is why, you should test the car engine. That is why, you may need to use an expensive machine what is found in the car manufacturer center. The engine P1603 Code is found from your car when the car engine was tested. This engine explains about the problem and by the meaning of the code, it becomes easier to fix the car engine. You need to read the manual of the car engine if you want to know more about the problem. You should solve the car engine by help of an automobile engineer.