I might be tempted to look for an original air box and pipe kit, or maybe a silicone one that accommodate all the breathers and sensors the ecu is looking at. purpose of the silicone hose is to smooth the air with less restriction, does that one? bet it’s got a lovely red cone filter too. Can you tell i am not a fan, but you do you.
There is also an air monitoring sensor (yellow circle) that connects to the pipe directly on the turbo (in the photo going from the air box, looks like it’s coming out of the brake fluid reservoir to the Turbo).
Your fault code could be caused by the open breather and unconnected sensor/malpositioned sensor.
However it’s probably the pierburg diverter valve, visible as the black plastic thing (blue circle) mounted on the turbo, with a triangle base and 3 Allen key bolts In the pic. Over time the orange/red (black) diaphragm seal, work hardens and can split, whistling at higher rpm, throwing up codes and car not running correctly or less efficiently. If the numbers have faded or been wiped of shout back and I’ll get you them.
Buy a pierberg, matching numbers to the original, widely available and not overly expensive.
