Hi I am trying to investigate a pressure issue. 2004 TD4 manual

Could anybody with a diagnostic confirm with car in ignition mode what happens to LP pressure after the pump stops priming (1 minute)?

My pressure drops from 360Kpa to 99Kpa. Also LP drops to 99Kpa when engine dies due to a HP problem. Car starts though.

Is this drop normal?

Cheers!

360Kpa is correct. 99Kpa sounds like atmospheric pressure. There's no non return valve in the system, so the low pressure will drop off if the LP isn't running.