The system is designed to automatically add more torque to the rear wheels when a wheel slip is recognized. If you say it is engaged at all times, my first thought would be a faulty wheel speed sensor that is tricking the system into believing you are spinning a wheel.
This can be tested easily using a live data scan too and checking the wheel speed PID (Parameter Identification) to see if one wheel's speed is different than the others.
Is that possible for you to have done or do? Also, by any chance is the ABS light on?
The first thing I would suggest is to do what I mentioned above. However, I identified diagnostics if the system is always in AWD. Note that if you feel it is engaged, I am basing this on the idea that you likely feel it in the steering (fights to turn) or vibration when accelerating.
Let me know what I can do to help.
See pics below.
Images (Click to enlarge)
Tuesday, December 27th, 2022 AT 8:08 PM