The car engine C1790 Code has different meanings and you have to find the correct meaning among different meanings. The general meaning of the code is found online and other car manufacturer have provided also meanings of the code. You need to seek the meaning what is relevant with your car. You need to know the name of the car manufacturer and model of the car. If you use wrong meaning of the code, it may create new problems. So, you should be careful when you choose the meaning of the engine code. After solving the car engine, take the car for a test drive.