Hill Descent Control (HDC)
WARNING: This page is about a different car, the 2018 Land Rover Discovery Sport. However, it is still accessible from the selected car via links, so may be relevant.
The HDC mode assists the ABS control module in controlling the downhill speed of the vehicle. When HDC is active, the TCM selects the most appropriate gear for the descent to maximize engine braking.
Maximum engine braking is applied using a shift map which initiates later upshifts and early downshifts.