Nissan Primeaster dci 100 lack of power/limp mode

Problem advuce greatly appreciated.



We have a 1.9 dci 100 van which has a lack of power and depending on how it's pulling especially in 5th and 6th gear goes into limp mode. Glow plug lamp and electronic warning lamp located under liw fuel level lght comes on at 2100 revs.



Ignition can be turned off and on again goes back to normal until 2100 revs reached when the same thing happens.



Changed egr valve, boost pressure sensor and mass air fliw meter already. Diagnostic shows boost pressure fault.



Thanks



Mike