I’ve just worked through solving a check engine light code for the PCV system on a 2017 GL 300 4matic with 73,000 miles. If you get the PCV code, it’s a big repair. This turbo 2 L motor has the PCV valve factory attached to a system of hoses and sensors the dealer parts guys jokingly refer to as “the octopus”. It’s often on a long back order.

Pelican Parts has the MB remanufactured part Which fit perfectly. It’s a six hour adventure to remove and install it however. There’s nothing super technical about this job, it’s just very difficult access to a lot of the fasteners and parts that takes so long. My dealer wanted $400 for the part and $1,600 in labor to install it, which is why I did it myself. And you will need every length of extension in your tool kit, as well as E 10 and a E12 universal Torx sockets.

I took notes so can provide a basic procedure if anyone wants to tackle this maintenance project. I’ve heard these engines commonly start throwing the PCV system code at around 75,000 miles.