There are several causes involved for the engine P1803 Code problem. It is important to know the real cause of the car engine problem. If you do not know the reason of the car engine problem, it is difficult to solve the car engine. You must look for the real meaning from the car engine manual to know the real cause of the car engine. Do not drive the car with the engine fault what may make more serious problem in the car engine. You must take the car to automobile repair center to fix the car engine problem as soon as possible.