Freelander 1 Td4 Turbo solenoid

Have continued the above thread:
https://www.landyzone.co.uk/land-rover/td4-lack-of-power-at-70mph-fixed.77147/
But does anyone know how the turbo solenoid works?
What is the control voltage, is it open and powered closed or other way around? Steps or continuously variable?
Want to make a test jig to test them.
Thanks.

Answered one question with a look through Rave !!
The boost pressure sensor provides a feed back a signal relative to inlet manifold pressure to the ECM. The ECM
also calculates engine load and uses this along with the boost pressure sensor input to send a signal (PWM) to the
vacuum control module to determine the amount of vacuum supplied to the vacuum control cell. The amount of
vacuum operates between 0 mBar to 640 mBar depression (640 mBar with the vanes fully closed-maximum boost).

So it is a PWM signal, but still don't know what signal the solenoid (or Vacuum control module as LR call it) receives for open or closed.

The solenoid is simply a coil that pulls the actuator rod against a spring to adjust the turbo vanes. The ECM PWM signal varies the width of the 12V pulses, when then determines how far the solenoid pulls in.

It works similar to Idle Control valve but ddrives the vanes instead of a valve https://motorsport-electronics.co.uk/onlinehelp/html/PWMBasedIdle.html

Thanks, yes it does the above via a vacuum line which operates the actuator as a result of the solenoid allowing a vacuum path or not. This varies with the PWM signal.
To make a test rig I need to know what the PWM signal looks like, it is 5V or 12V.? Also what frequency PWM does what to the solenoid? The one I just changed seemed to be open to pass vacuum with no signal at all. Not sure if the PWM then closes the path when applied?