When the car engine is checked, then the engine P0812 Code is found easily. Do not try to fix the car engine if you are not an expert automobile engineer. Like the all the car engines, this car engine system services especially advanced hydraulic lifters what is known as switching roller followers for the engine P0812 code intake and finish valves. The lifters can be distorted by disengaging an inner locking pin. The locking pin is disengaged using solenoids to modify oil weight fed into the lifter. Do not drive the car with the car engine problem and fix the car engine as soon as possible.