Meaning of the code P0001 is fuel volume regulator control circuit or open. This problem may occur due to the Wiring, regulator control solenoid. If the problem is not fixed quick. The code of the P0001 does not go away auto. Malfunction indicator lamp is also illuminated with the trouble code what is stored. The car owner should check the plug to the fuel regulator, corrosion in the sensor connector, sensor wiring to the ECM (if it is damaged), check fuel pressure regulator, check fuel pump and check ECM. It is important to check the data from the ECM. Examining all stuffs such as wiring and leaks, etc.