Ride & Handling Optimization (page 7 of 7)

ignition on and off cycle.  
 
Terrain Response Sub-System Faults  
 
If a fault occurs in a sub-system, the driver is alerted by the illumination of a warning indicator and/or an appropriate 
message for that sub-system in the instrument cluster message center. There will be no warning of a Terrain Response 
system fault.  
 
When a sub-system fault is present and the driver attempts to select a different Terrain Response program using the 
rotary control or at the next ignition on cycle, a message 'SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE' will 
appear in the message center. This implies that the Terrain Response system has a fault, but only because a sub-system 
fault is preventing its operation. This message will be displayed for 5 seconds per ignition cycle, but is repeated if a further 
selection is made by the driver using the Terrain Response rotary control or at the next ignition on cycle.  
 
NOTE:  

 
It is not possible for the Terrain Response control module to cause any fault behaviour (warning indicator illumination or 
message generation) in any of the five sub-systems. Illumination of a sub -system warning indicator and/or a sub-system 
related message will never be associated with a Terrain Response control module or Terrain Response system fault.  
 
The sub-system control modules can detect a fault with the CAN signal from the Terrain Response control module. If a 
fault in the Terrain Response system is detected, the sub-system control modules will operate in the 'special programs off' 
setting. The sub-system control modules will record a fault code for a failure of the Terrain Response CAN signal. These 
faults can be retrieved using T4 and will provide useful information to indicate investigation of the Terrain Response 
control module or the CAN network.  
 
Terrain Response Rotary Control or Control Module Fault  
 
If a fault occurs in the Terrain Response rotary control, all rotary control icon amber LEDs will be turned off (background 
illumination will remain on) and rotation of the rotary control is ignored. The instrument cluster message center will display 
a message 'SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE' when the fault occurs, if the fault is present and 
the driver attempts to select a special program (if the control module is able to do this) or at the next ignition on cycle.  
 
If a failure of a rotary control icon amber LED occurs, the Terrain Response system will still function. Any selected special 
program will default to 'special programs off' at every ignition on cycle, except if default from grass/gravel/snow program 
has been disabled, in which case the grass/gravel/snow program will remain selected.  
 
The Terrain Response rotary control and the control module are an integral unit. If a fault occurs in either component, the 
whole unit will require replacement.  
 
CAN Faults   
 
If a CAN fault exists and prevents Terrain Response system operation, all of the Terrain Response rotary control icon 
LEDs will be illuminated and rotation of the rotary control is ignored.  
 
If the instrument cluster does not receive a Terrain Response system CAN message from the Terrain Response Control 
module, the message 'SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE' will be displayed when the fault occurs 
and will be repeated at every ignition on cycle.  
 
User Error  
 
The following incorrect usage of the system may be misinterpreted as a system fault:  
 

l

Engine not running - Program changes and driver advisory messages are only available with the engine running  

l

Rock crawl program selected but transfer box in high range  

l

Special program change attempted with DSC or ABS active (this includes ABS cycling which is operational when 
HDC is being used on slippery or loose surfaces).  

l

Special program change attempted with overheat condition present on center or rear differential.  

The message 'SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE' can also be generated by a fault in the 
Terrain Response rotary control or control module. See following section for details of rotary control or control 
module faults.