Hill Descent Control

HDC is automatically switched on or off and target speeds are adjusted in response to the Terrain Response program selected. The responsiveness of the HDC function is also increased where required.

Automatic operation of HDC aims to assist the driver by switching the system on or off when it is of most benefit. HDC is only automatically switched on when the mud/ruts program is selected. HDC is not automatically selected in other programs.

INCORRECT PROGRAM USAGE

Selection of an inappropriate program is discouraged in the following ways:

• The active program icon is continually displayed in the instrument cluster message center
• The Terrain Response control module 'locks' out certain functions in some programs, for example:
  • cruise control is only available with the special programs off or grass/gravel/snow program
  • transmission 'Sport' mode is deactivated in all special programs.
• When the ignition has been in the off mode, continually for more than 6 hours, the Terrain Response system defaults to the special programs off.

Selection of an inappropriate program for the terrain conditions will not endanger the driver or cause damage to the vehicle. Continued use of an inappropriate program may reduce the life of some components. The driver may notice reduced vehicle response, with the engine and transmission being less responsive than in special programs off. Also, in some programs, HDC will remain on, signified by illumination of the HDC indicator in the instrument cluster. The driver may also notice torque 'wind-up' in the active on-demand coupling causing a braking effect when the vehicle is maneuvered in some special programs.

DRIVER INFORMATION

The high-line instrument cluster fitted to all vehicles with Terrain Response, contains a message center which displays vehicle information to the driver. The message center contains the Terrain Response program icons which display the currently selected program. If no symbol is displayed, no special program is selected and the system is in 'Special programs off'.

Any required changes to the sub-systems are also passed to the driver in the form of indicator illumination in the instrument cluster or appropriate messages in the message center, 'HDC OFF' for example.

In certain operating conditions, the Terrain Response system also displays advice or warning messages to ensure the driver is using the vehicle to its full potential, for example, steering angle is displayed in the message center to avoid driving in deep ruts with steering lock applied.