p0235 is low boost.
Which engine?
Get a cheap OBD2 gizmo and check MAP pressure and check it goes up when under load/requesting turbo.
Could be blocked intercooler, blocked/split turbo pipe, MAP sensor, stuck/not working VNT turbo control, stuck wastegate etc.
See my blog below and search for p0235 - there is a troubleshooting guide for a TRANSIT - clearly not the same van, but the logic is there. I have no experience of NV200 yet.
Which engine?
Get a cheap OBD2 gizmo and check MAP pressure and check it goes up when under load/requesting turbo.
Could be blocked intercooler, blocked/split turbo pipe, MAP sensor, stuck/not working VNT turbo control, stuck wastegate etc.
See my blog below and search for p0235 - there is a troubleshooting guide for a TRANSIT - clearly not the same van, but the logic is there. I have no experience of NV200 yet.