How to troubleshoot the EGR valve control solenoid?

That is a linear valve so it might be difficult to test but you can try a continuity test between the two coil windings.

Here is a guide and the EGR control valve wiring diagrams:

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Check out the images (below). Please let us know what happens.