Im trying to use after touch to trigger the B3 fast tone wheel when I press - but it wont learn it - I try to assign parameter 358 - rotary fast speed. And use edit to program Aftertouch (and it asks a channel -?) so I cleared that and just used my midi monitor to see the Aftertouch and it doesn’t show
What plugin are you using?
Are you trying to map Channel Pressure ?
How looks you MIDI mapping?
AFAIK the Arturia Keylab essentials has no aftertouch for the keybed?! Only the Pads provide polyphonic aftertouch 
1 Like
Found this
All the KeyLab series have aftertouch, actually polyphonic aftertouch, on the pads.
The KeyLab Essential series (original or Mk3) do not have aftertouch on the keys.
The KeyLab series (original, Mk2 or Mk3) have channel aftertouch on the keys.
1 Like
Thats dissappointing! I guess Ill work around it 
I am using the Sustain Pedal to toggle the Leslie Speed.
Ironically, enough, it seems that my sustained pedal is not needed on both songs where I could use the after touch for the organ-That sounds like a great workaround