Expression pedal for cutoff - problem...

[Storm Music]

Any recommendations for an expression pedal as control pedal for the virus ti polar?
I used to use a boss expression pedal for my virus indigo - and set the control pedal to #40 (cutoff filter), and it worked perfectly.
Now, however, on the TI polar the pedal does not "cover" the whole range of the cutoff filter, so to speak.
On my indigo when the pedal was down, the filter was 0, and when up 127.
Now it just doesn't go from 0-127 for some reason.

The same thing happened, when I tried a roland expression pedal for my indigo...

Any clues?
thanks

[Storm Music]

Please...