u/Dry-Caramel7006

Hey guys, I drive a 2013 cls 550 with a m278 engine. Just recently I fixed a leaking coolant hose in the back of the engine (Left Cylinder Head Coolant Feed Line). After fixing it all of a sudden a check engine light came on stating that my turbocharger isn’t getting enough air pressure. I do hear a slight hissing sound at idle and noticeable power loss when driving. I asked my mechanic to check the area to see if anything is loose or cracked and he said all is well. Even though I hear the hissing sound at the back could it be that my turbocharger failed? Trying to see all the possibilities of why it isn’t getting enough air pressure. Let me know. Thanks guys!