The trouble P0290 Code is important thing and it helps the car engineer for solving the car engine properly. Due to negligence or not fixing the car engine, new problem may start from the car engine. If you use wrong meaning of the code, you may get new problem in the car engine. The letter P means powertrain and when the powertrain is fixed, the engine code will not appear on the engine code reader screen if you fix the engine. You should not try to fix the car engine if you are not able to solve the car engine. You must give the car to automobile engineer for solving the car engine problem.