The engine P0309 Code is a common code what is found in many car engines and you must know the meaning of the code for solving the car engine. The meaning of the code should be correct what is found from the car engine manual. The automobile engineer must look for the right meaning of the code before solving the car engine. By the right meaning of the code, the problem of the car engine is easy to solve. Do not drive the car with the car engine problem, you may face terrible problem for using faulty car engine. When the car engine is ok, test the car engine by a test drive.