2C-T Passenger Side Vacuum Switching Valve - What does it do, and is it need?

[Townace King]

Hello all,

I have recently rebuilt a 2C-T in a Toyota Townace CR30. In the process I'm needing to replace the passenger side vacuum switching valve. I'm wondering if any of you smart people out there knows what this one does, and whether I actually need it.
The Exhaust Gas Recirculation has been deleted.
Part number: 25819-64040
Manufacturer: Denso

Here's a link to the part, as well as a diagram containing it: https://www.amayama.com/en/part/toyota/2581964040

Thanks in advance for your help!

Townace King