Finding the right meaning of the car engine P3431 Code is very important step for solving the car engine problem. You must appoint an automobile engineer to check and solve the car engine problem. Like the all car engines, this car engine method employs particularly developed hydraulic lifters what is known as switching roller followers for the engine P3431 code intake and finish valves. The lifters can be collapsed by disengaging an inner locking pin. The locking pin is detached using solenoids to change oil pressure fed into the lifter. When the car engine is fully ok, you must take it for a test drive.