Unless you were talking about this
AWD has separate strategies for Normal and Sport modes. In Normal, the system prefers front-drive for fuel economy, but may switch automatically to AWD under certain conditions, including detection of a low-traction road surface and driver operation of the throttle. At road speeds under 9 mph (15 km/h), AWD also automatically engages to anticipate a possible sudden hard acceleration or any acceleration if the road surface traction drops, as detected by vehicle chassis electronics. When AWD is engaged, the split is 60-40 front-rear, although the dynamic multi-map electronics can push it to a maximum of 50-50.
AWD is an always-on, key part of Sport Mode, and the electronic stability control (ESC) broadens the allowable yaw range. As managed by the Drivetrain Control Module, AWD is engaged both front-to-rear and at the rear axle; no rear axle disconnect is possible as as it is in Normal mode.
There's always some rear torque bias in Sport Mode, derived from the accelerator pedal position and the delta from the previous position. The actual Sport Mode torque transfer to the rear is based on the available torque from the engine, vehicle speed, yaw rate, and vehicle grade. The system uses an enhanced torque map for launch modes, although there is no specific launch control system for the driver to select on the 200.
I've had the PTU and my driveshaft replaced on my cherokee, and prior to them being replaced (due to bearings) it was super easy to know exactly when the rear end was getting power as, it made noise as power was sent to the rear wheels. The AWD operating below 9mph is 100% accurate and it always engages on takeoff however it can and will disenegae at temps below 37f after you get up to speed ~20mph. It gradually tapers off after initial acceleration.
2 other time it would engage when it was not engages is.
1. Using ERS (electronic range select) on the cherokee it just limits the max gear the trans can be in
2 If the ESP button was turned off (either partial or full off) that started sending power to the rear wheels.
Again there is literature out there explaining how things work, but it doesn't always explain ALL the variables