Changing the PCV valve on my 04 Corolla. I went to the dealership, hoping to get the correct part. Even though I gave them my VIN, it turns out there are two parts, both of which look outwardly similar in photos on the web. The part numbers are 12204-22040 and 12204-22050. The dealership recommended that I remove the one that is on there and see which one it is. But the PCV valve on the car is aftermarket. Does anyone know what the difference is between 12204-22040 and 12204-22050, and how I can figure out which one should be on the car (bearing in mind that the VIN does not seem to be the answer)?