Crank no start p0200 (12)

[Lewy777]

Hi all
Recently brought a mk7 2.2 tdci 2006 transit as a non runner. I’ve been told it requires an ecu.

I have code p0200(12) for circuit malfunction. I have noticed there seems to be a puddle of water around injector 1 specifically.

Fuel line going from Filter housing seems to have part air part fuel in the line and doesn’t move when cranking or when running on easy start.

What would be the most obvious things to be checking? I’ve cleaned up about 5 earth points in the engine bay. Checked all fuses and replaced old burnt ones and any broken ones. Visually checked around the injectors and wiring but nothing visible. New battery.

Also have no buttons working on the keyfob - immobiliser light flashes as normal and not fast.

Thanks