The explanation of the B1990 Code is necessary for solving the car engine problem. You can solve the car engine if you have expensive machines for solving the car engine. Do not drive the car if you know the problem is on the body of the engine. The general information can be found about the problem from the dictionary meaning of the code but the real information is necessary if you want to get the real meaning of the code. That is why, you have to depend on the manufacturer information like model and brand of the car. Do not try to fix the car if you do not know how to fix it.