After many avenues of "trial and error", my Faderport 16 now can control the volumes of the tracks in Sonar. As I mentioned before, the control of the track volumes worked fine in Studio One, but not in Sonar. The Faderport could only receive automation control and not send track volume control information. Using the HUI driver worked in Sonar. I now have the volume control back again.
Not sure what changed in Sonar, but this workaround fixes the problem.
I hope this helps those that use their Faderport 16 for more than one DAW.

I did rejoice when I switched to the Hui option, then,my faders worked.

But.........when I tried the rest of the Faderport 16 controls, nothing else worked.

Switching back to MCU/Sonar option, everything worked again except for the faders.

I do not recall when the Hui option was added to an update, but there must be a correlation between the two.

Meanwhile the Faderport 16 works very well with Studio One.
This is an issue for folks that use Sonar, as well as Studio One.

Please update your signature (see link and example in mine) with your system specs to help in answering your questions.

What version of Sonar are you running?
What version of Faderport 16 firmware are you running?
What version of Universal Control are you running?
What operating system are you running?

Have you submitted a Support Ticket (see link in my signature) for this yet?