Vw Transporter T6 2016 Wont Rev Above 1700 Rpm

Hi all I have a problem with a vw transporter t6 2.0 tdi it wont rev above 1700rpm in any gear and stationary.

if you change down in the gears the van will hold back until it the engine speed drops to 1700 rpm. Its like the ecm is limiting the engine speed. I did disconnect the battery over night and it rectified itself for 2 miles then reverted to 1700rpm limit

it has no fault codes in any systems.

I have changed the fuel filter, changed the crank sensor, blanked the egr, all no change, checked fuel pressure all ok. Removed sensors from dpf to make sure there is no restriction, no change. Checked valve timing, all ok. Checked ecm for water ingress to connector and connector pins. Checked all earths to ecm.

if anyone has any ideas it would be greatly appreciated