Vito 122 fault code help please?

[ED209]

Hello, I have a 2013 Vito 122 with the om642 engine. I have recently had the swirl flaps deleted and mapped out however the van is now intermittently going into limp home mode. When plugged into the star system it is giving the code

P126800 Component Y77/8 (boost pressure regulator) reports a fault

Can anyone please advise me exactly which component this is referring to? Google keeps pointing me in the direction of the turbo actuator which as far as I can tell is Y77/1 And I assume a different component.