Due to the engine problem, the engine U1166 Code has come on the screen of the car engine code reader. Now according to your car manufacturer’s meaning, you need to find the real meaning of the code. In the manual of the car, you will get detail about the car and by following those information, you can easily find the real meaning of the car engine code. In the car engine manual, you will get the real meaning of the engine code. Do not allow the meaning of the code what is found from correct source. Once the car engine is ok, then you take it for a test drive.