Compass Mini/Trip Computer

The Compass Mini-Trip Computer (CMTC) is located in the overhead console on models equipped with this option. The Compass Mini-Trip Computer module features a large Vacuum Fluorescent Display (VFD) screen for displaying information, and four back-lit push button function switches labeled C/T (compass/thermometer), RESET, STEP, and US/M (United States/Metric Scale).

The Compass Mini-Trip Computer module contains a central processing unit and interfaces with other electronic modules in the vehicle over the Programmable Communications Interface (PCI) data bus network. The PCI data bus network allows the sharing of sensor information. This helps to reduce wire harness complexity, reduce internal controller hardware, and reduce component sensor current loads. At the same time, this system provides increased reliability, enhanced diagnostics, and allows the addition of many new feature capabilities.

The Compass Mini-Trip Computer module contains six informational displays which can be displayed using the four outer buttons on the overhead console. When the vehicle is first turned ON:

• CMTC blanks the display for a half second
• Displays whatever was being viewed when the ignition was last turned OFF

The CMTC may also be integrated with the Universal Transmitter. If so, your CMTC module will have three buttons centered together between the outer four buttons. Below the three buttons are corresponding dots to indicate which button you are using.

The Compass Mini-Trip Computer includes the following display options:

• Compass and thermometer  - provides the outside temperature and one of eight compass readings to indicate the direction the vehicle is facing.
• Average fuel economy  - shows the average fuel economy since the last trip computer reset.
• Trip odometer  - shows the distance travelled since the last trip computer reset.
• Blank screen  - the CMTC compass/thermometer/trip computer VFD is turned off.

If the vehicle is equipped with the optional Universal Transmitter transceiver, the CMTC will also display messages and an icon indicating when the Universal Transmitter is being trained, which of the three transmitter buttons is transmitting, and when the transceiver is cleared.

Data input for all CMTC functions, including VFD dimming level, is received through PCI data bus messages. The CMTC module uses its internal programming and all of its data inputs to calculate and display the requested data. If the data displayed is incorrect, perform the SELF-DIAGNOSTIC TEST  . If these tests prove inconclusive, the use of a DRBIII(R) scan tool and the BODY DIAGNOSTIC PROCEDURES information are recommended for further testing of the CMTC module and the PCI data bus.

The CMTC module cannot be repaired, and is available for service only as a unit. This unit includes the push button switches and the plastic module and display lens. If any of these components is faulty or damaged, the complete CMTC module must be replaced. The incandescent bulbs used for CMTC push button back-lighting are available for service replacement.