trafic 115 dci 2007 wont rev above 2500 rpm

hi im currently repairing a trafic van, the vacuum system on the van has been incorrectly fitted which meant all the vacuum lines for turbo and egr and sensors etc was all in the wrong place, i have now placed all the pipes in the correct place barring one pipe that wasnt correctly fitted so was looped the pipe i have left is located on a sensor that is bolted to the right upper side of the engine via 2 bolts, all the vac lines that go to the t piece pipe section and solenoid are correct but i am left with one pipe and no where for it to go has anyone got any better diagrams or know where the mystery pipe goes, the sensor i am talking about has one pipe coming in from the t piece section one pipe going out to the front of the engine to a valve on the egr system and them im left with the mystery pipe can anyone help please

trafic 115 dci 2007 wont rev above 2500 rpm