2011 e70 X5 not starting 4B90 Rail pressure monitoring on start up

[ChristyMcL]

My 2011 X5 40d n57 engine cut out while driving and now won't start.

Codes are :
004B90 Rail pressure monitoring on engine start

004610 Rail pressure plausibility pressure controlled

004570 Rail pressure plausibility delivery controlled

I have tested the fuel pre supply system and it is showing the correct pressure.

But when I test the fuel rail pressure while cranking the pressure is way to low to start at 10.4 bar .

Is there any way I can narrow it down further without just replacing the High pressure fuel pump or the fuel rail sensors or what is it likely to be ?

[wcs531]

The CP4 pumps in the n57 are known to self destruct and send metal fragments into the fuel system, including the return line back to the fuel tank.

I do not know the best method to check this but I would search the F15 x5 forums since we did not get the n57 in E70s in the states