The engine U1203 Code is important thing and real meaning of the engine is found in the car engine manual. Do not use wrong meaning of the engine code for solving the car engine problem. Due to use of the wrong meaning of the code, the engine gets some new problems in the car. The automobile meaning of the engine is not verified solution or meaning for your car engine problem. That is why, you must not wrong meaning of the engine code for solving the car engine problem. If you fix the car network problem, the engine problem will be fixed.