I have a P2885 boost pressure variation code that popped up after doing the water pump and the tube that runs from the pump housing to the thermostat housing (which needed to be removed for the install.)

My question is what exactly controls the boost pressure that the turbo makes? I know the wastegate is vac actuated via the vacuum splitter box under the intake manifold which ultimately is what makes boost, but is there something that controls the amount of vacuum the wastegate sees?

I checked the vacuum lines from the wastegate diaphragm and everything seems fine. I also double checked all of the intake tubing that sees boost and everything is tight, plus no sounds of the leaks.

When watching the target value and the actual value of absolute manifold pressure on my scan tool, it was close, but a bit low on the actual value.

Any thoughts would be extremely helpful...

 

I believe it's the Vacuum Regulator Solenoid it's under the Intake....Mine buzzed forever when I shut the car down...ECS has them for sale...the Vac hose on it that leads to the wastegate did not stay on so...zip tied that ***** and Boom...fixed...Check that part..
R56 N14..I replaced it anyway..check youtube as well a guy posted a how to...

 

Yayyyy thank you so much that is exactly what I was looking for.

I believe I have a small vac leak from bumping that solenoid when I was installing the coolant pipe.

 

Yep I did the same thing...and when I carbon cleaned the valves I took it off again...
See if you can relocate this part above the intake somehow?...Strange place for this part...IMO...ECS Tuning calls it a Pressure Converter Mfg#: 11657599547 GMini Part

 

Yes talked about it here:

11657599547

https://www.northamericanmotoring.co...ing-off-2.html