Boost pressure reading, what should they be?

[surfer_x]

I have the OM-651 engine, in a sprinter 313CDi

On the freeway I get just under 23psi of boost (shown by cheap OBDII scanner on my phone: torque app)

When the vehicle starts a regen the boost seems to be limited to around 10psi it hard to tell as if push too hard I get a boost pressure fault, and the regen stops.

What should I be seeing?

Trying to gather as much info before my next trip to the dealer.

 

[Westheath]

Whilst its going a regen keep the speed steady and let it complete the cycle.

 

[Steve@Avantgarde]

Always measure turbo boost pressure with a gauge with the engine off. The reason for this is there is too many variables around the boost system for it to be inaccurate.

Using a boost pressure tester you should see between 3-4 bar.