Ride & Handling Optimization (page 6 of 7)

l

The active program icon is continually displayed in the instrument cluster message center  

l

The Terrain Response control module 'locks' out certain functions in some programs, e.g. , 

¡

cruise control is only available with the special programs off or grass/gravel/snow program  

¡

transmission 'Sport' mode is deactivated in all special programs.  

l

When the ignition has been in the off position, continually for more than six hours, the Terrain Response system 
defaults to the special programs off. (The dealer can prevent the Terrain Response system defaulting out of the 
grass/gravel/snow program using T4 or the driver can enable or disable the default out of the grass/gravel/snow 
program using the Customer Personalisation feature).  

l

The rock crawl program is only available with the transfer box in low range.  

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 the 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 center and rear differentials causing a 'braking' effect when the vehicle is 
manoeuvred in some special programs.  
 
The use of the special programs in the Terrain Response system is monitored by the Terrain Response control module 
which records the mileage and time the vehicle has operated in a specific program in high and low range. This information 
can be retrieved using T4 and used by the dealer technician to check customer concerns, e.g. high fuel consumption 
which may be due to continued use of a certain program.  
 

Driver Information  

The high specification 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 subsystems 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 or air suspension height change 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, e.g.,  
 

l

Steering angle is displayed in the message center to avoid driving in deep ruts with steering lock applied  

l

gear information is displayed to recommend a gear for slippery conditions  

l

if the system automatically provided off road ride height, but the driver subsequently lowers the vehicle to normal 
height, then the system may advise that this will cause a risk of grounding.  

The messages which can be displayed in the instrument cluster message center are detailed in the Information and 
Message Center section. For additional information, refer to  

Ride and Handling Optimization

 (204-06 Ride and Handling 

Optimization)  
 
 

DIAGNOSTICS  

The Terrain Response control module stores information on detected Terrain Response faults and CAN errors which can 
be interrogated using T4. The Terrain Response sub-systems and the instrument cluster also store fault information 
relating to CAN errors from the Terrain Response control module.  
 
The control module also stores the miles travelled and time elapsed in high range for the individual programs and in low 
range for use of all programs which can also be retrieved using T4. This information aids diagnosis of the Terrain 
Response system and also provides an indication of Terrain Response system abuse by the driver which can lead to 
premature component failure.  
 

Terrain Response System Fault Diagnosis  

Terrain Response relies on the correct functionality of the five sub-systems. If one of the sub-systems develops a fault, 
the Terrain Response system will not function, even though the fault is not in the Terrain Response system. The Terrain 
Response control module and rotary control should only be investigated if there are no apparent faults in any of the sub-
systems. If a fault in a sub-system is subsequently corrected, the Terrain Response system will function normally after an