Hi Gremlin,
Good that I have entered the error into the error database...
/viewtopic.php?t=28621&highlight=p2004
It refers to an error that occurs when switching between the switchgear. Especially with non-turbocharged gasoline engines, resonance induction utilizes the intake manifold to achieve a better engine filling rate.
This requires a long intake path at low speeds, and a short intake path at high speeds.
The valve you mentioned switches between short and long intake paths. Rest siehe mein Link oben.
Regarding the function of the suction pipe in your motor: Search for "SSP 359" and refer to page 48.
It would be great if you could post a picture of the valve.
Best regards, Rainer