W211 low fuel pressure under hard acceleration star code 22e7

[mshah70]

Hello
Owner of merc w211 e220 Cdi 2007
226k

I am having low fuel pressure issues.
Star diagnostic code 22e7
Check high pressure control ‘rail pressure too low’

When i open up the throttle (hard acceleration) going up a hill or on motorway, the engine light comes on and car goes into limp mode.

I used Star to check high pressure control, Quantity control valve, pressure regulator all sensors seem To be in working order.

I tested the low pressure circuit, fuel pump seems to be in working order.

Please i need some help.