On my PWT this is caused by simulated engine vibration and can be controlled by the 'SHO' option in the tuning menu (on the wheel it self).
No, those two motors can simulate either:
-wheel lock due to braking - ABS function on the wheel
-engine vibration if ABS function turned off
Vibration strength is controlled through the "Sho" setting.
Other effects are simulated by the main force feedback motor.
where do you go to make a new profile?