The control unit also stores mileage and elapsed time data for individual programs, which can then be read out using the IDS. It simplifies the diagnosis of the Terrain Response system and allows the driver to detect misuse of the Terrain Response system, which can lead to premature component failure.
This information can also be used to verify customer complaints, such as increased fuel consumption caused by continued use of a particular program.
Troubleshooting the Terrain Response System
The Terrain Response system depends on the correct operation of 4 subsystems. If any of these subsystems fail, the Terrain Response system will not function, although this is NOT a malfunction of the Terrain Response system itself.
The Terrain Response control unit and rotary control should only be inspected if there are no obvious faults in any of the subsystems. If the subsystem malfunction is subsequently corrected, the Terrain Response system will return to normal operation after an ignition on/off cycle.
Terrain Response Subsystem Malfunctions
When a malfunction occurs in a subsystem, the driver is notified by illuminating a warning light or by displaying the appropriate message for that subsystem in the instrument cluster's message center. There will be no warning of a malfunction in the Terrain Response system.
If there is a subsystem fault and the driver attempts to select a different Terrain Response program with the rotary control or the next time the ignition is turned on, the message box will display "SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE" (System failure, special programs not available). This message indicates that the Terrain Response system is malfunctioning, but it is only caused by a subsystem malfunction. This message will be displayed for 5 seconds when the ignition is turned on, but will be repeated if the driver tries to use the Terrain Response rotary control or after each subsequent ignition.
NOTE: The message appears on the display: "SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE" (SYSTEM MALFUNCTION. SPECIAL PROGRAMS NOT AVAILABLE) can also be caused by a problem with the Terrain Response rotary knob or control unit. Refer to the following information for a detailed description of rotary encoder or control box failures.
Terrain Response ECU cannot cause malfunctions (activating an alarm or issuing a warning) any of the 4 subsystems. The activation of a subsystem warning light and/or the associated message is NEVER associated with the operation of the Terrain Response control unit or with a malfunction of the Terrain Response system.
Subsystem control units can detect a malfunction based on a signal transmitted by the Terrain Response control unit via the CAN bus. If a malfunction of the Terrain Response system is detected, the subsystem control units will operate in the mode of disabling special programs ("Special Programs off"). The subsystem control units will write a DTC based on the signal transmitted by the Terrain Response control unit over the CAN bus. Information about these faults can be read using the IDS and is useful for diagnosing the Terrain Response control unit or CAN bus.
Malfunctioning rotary control or Terrain Response control unit.
In the event of a Terrain Response rotary control failure, all yellow LEDs on the control symbols will turn off and rotation will be ignored. If a subsystem malfunctions, a message appears in the message center of the instrument panel "SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE" (System failure, special programs not available) in the event that a malfunction is present and the driver tries to select a special program (if the control unit can do it) or the next time the ignition is switched on.
The rotary knob and control unit of the Terrain Response system are one unit. The failure of one of these elements requires the replacement of the entire assembly. BEFORE REPLACING THE CONTROL UNIT OF THE TERRAIN RESPONSE SYSTEM, MAKE SURE THAT IT IS DEFECTIVE AND NOT THE CONTROL UNIT OF ONE OF THE SUBSYSTEMS.
In the event of a CAN bus failure preventing Terrain Response from operating, all amber LEDs illuminate the rotary control symbols and ignore rotation.
If the instrument panel does not receive a message via the CAN bus from the Terrain Response control unit, the following message will appear in the information center display in the event of a malfunction: "SYSTEM FAULT SPECIAL PROGRAMS NOT AVAILABLE" (SYSTEM MALFUNCTION. SPECIAL PROGRAMS NOT AVAILABLE), and this message will appear every time the ignition is turned on.
User error
The system response to the following incorrect user actions may be mistaken for a system malfunction:
- The engine is not running - the program is changed and messages are displayed only when the engine is running
- An attempt is made to change a program while DSC or ABS is active (this includes anti-lock braking system cycles when using the controlled descent system on slippery or loose surfaces).
- An attempt is made to change the program when the active clutch overheats.
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