The throttle is drive by wire so there is a position sensor on the pedal and a stepper motor to move the throttle.
Throttle valve on the JTD inlet manifold is 100% open at all times whilst the engine is running, and is vacuum actuated.
Electronic throttle pedal is picked up by the ECU, which then controls the amount of fuel being pumped in by the injectors and the pressure in the fuel rail - no actual throttling going on at all.
These engines run with massive excess air, so to increase the power/rpm the ECU just orders up a little more fuel to consume some more air, generates more exhaust which blows the exhaust turbine harder, generates more induction air, so the ECU can add a bit more fuel etc...
Download a free copy of MES (or use an app like Torque), plug in to the cars EOBD port, and pick up throttle position tag.. Should be able to see the valve that the ECU is seeing, and then see how it changes as you press the pedal..