Hi looking for advice I've got a man tge 180 and the pre heat light keeps coming on. We've changed the glow plugs, both turbos and the 4 sensors. Thought we had cracked it drove near 100 mile and pre heat light comes back on 
and goes into limp mode, coming up with error code PO2990 turbo under boost. But if you switch of ignition it clears it for another wee while. Any assistance with this would be much appreciated as am tearing my hair out
and goes into limp mode, coming up with error code PO2990 turbo under boost. But if you switch of ignition it clears it for another wee while. Any assistance with this would be much appreciated as am tearing my hair out