2004 TD4 sensor see photo

I am having problems with this thingy!! located on chassis N/S/F. When I plug the wires into it the engine management light comes on and the engine goes into limp mode, disconnect it and it's ok, any ideas please. I am not sure if its related but the turbo hose split and it was when I replaced the hose I noticed this plug was not connected. Thanks

fuel pressure sensor - new they cost from £75.00 to £125 - if memory serves correctly.

That is the fuel low pressure sensor trace the wiring back from the sensor to see where it fits into, you may find it will go to the fuel cut off switch or the ecu