The car engine P2504 Code gives some information about the car engine problem. The right meaning of the car engine is mostly useful. If you know how to check and fix the car engine, you should try to check and fix the car engine. Alike the all car engines, this car engine process works especially advanced hydraulic lifters what is known as switching roller followers for the car engine P2504 code intake and finish valves. The lifters can be distorted by undoing an inner locking pin. The locking pin is detached using solenoids to change oil compression nursed into the lifter.