The meaning of the engine U1104 Code is found from the car manufacturer and it is correct meaning of the code. Do not use wrong meaning of the code like automobile dictionary meaning. You will find the same code in different car engines from different car brand but do not follow any of those meanings for solving the car engine problem. The engine code U1104 is the main thing to verify the process of the VCT solenoid. A sticking or stuck VCt solenoid valve produced by corruption. Refer to car specific repair manual to achieve section tests for the VCT unit.