120408 what is the problem and give me one photo

The BMW code listed as 120408 is a charging pressure control error and the component is switched off as a consequence. You can see the diagram available here at the link - https://f30.bimmerpost.com/forums/attachment.phpattachmentid=1652247&stc=1&d=1499343368. This can be caused by the wastegate pressure converter, vacuum hose leak, and decreased throttle response. You will notice when the error is indicated You will notice the drivetrain malfunction when driving at higher speeds on the highway. You will want to inspect the pressure sensors and the wiring around them to make sure they are not damaged or defective. The cost for a new replacement wastegate pressure converter will vary from $180 - $200 depending on if it's an aftermarket or OEM product.