Driver/Vehicle Information Display: Description and Operation

COMPASS-MINI-TRIP COMPUTER
The Compass Mini-Trip Computer (CMTC) is a module located within the overhead console. This module displays the following information:
- Compass/Temperature
- Average Fuel Economy
- Distance to Empty
- Instantaneous Fuel Economy
- Trip Odometer
- Elapsed Time
- Miles to Service
- Tire Pressure Display (if equipped)
- Blank Screen

When the vehicle is first turned ON:
- Compass Mini-Trip Computer blanks the display for 1/2 second
- Illuminates all segments of the Vacuum Fluorescent Display (VFD) at full brightness for 1-1/2 seconds
- Displays whatever was being viewed when the ignition was last turned OFF

Compass Mini-Trip Computer may also be integrated with the Universal Transmitter. If so, your Compass Mini-Trip Computer module will have three buttons centered together between the outer four buttons.

The buttons operate when the ignition is in the ON position. The VFD will display the last display before ignition was turned OFF The four outer buttons operate:
- STEP
- C/T - Compass/Temperature
- US/M - English/Metric
- RESET

1. STEP BUTTON
Pressing the STEP button selects one of the following 5 displays:
- Average fuel economy
- Distance to empty
- Instantaneous fuel economy
- Trip odometer
- Elapsed time

2. C/T (COMPASS/TEMPERATURE) BUTTON
Pressing the C/T button selects the Compass/Temperature display.

3. US/M (ENGLISH/METRIC MEASUREMENT) BUTTON
Pressing the US/M button switches the display units between English and Metric readings.

4. RESET BUTTON
Pressing the RESET button resets the function on the display, provided that function can be reset. The functions which can be reset are Average fuel economy Trip odometer and Elapsed time.

The RESET button is also used to set the variance and/or calibrate the compass. Refer to the Variance Procedure and Calibration Procedure in this section.

ELECTRONIC VEHICLE INFORMATION CENTER
The Electronic Vehicle Information Center (EVIC) is located in the overhead console on models equipped with this option. The EVIC module features a large Vacuum Fluorescent Display (VFD) screen for displaying information, and back-lit push button function switches labeled CIT (compass/temperature), RESET, STEP, and MENU.

The EVIC 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 EVIC includes the following display options:
- Compass and temperature - 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.
- Distance to empty - shows the estimated distance that can be travelled with the fuel remaining in the fuel tank. This estimated distance is computed using the average miles-per-gallon from the last 30 gallons of fuel used.
- Instant fuel economy - shows the present fuel economy based upon the current vehicle distance and fuel used information.
- Trip odometer - shows the distance travelled since the last trip computer reset.
- Elapsed time - shows the accumulated ignition-ON time since the last trip computer reset.
- Distance to service - shows the distance remaining until the next scheduled service interval.
- Tire Pressure - shows tire pressure in each road tire.
- Blank screen - the EVIC compass/temperature/trip computer VFD is turned OFF.

The EVIC "Menu" push button provides the vehicle operator with a user interface, which allows the selection of several optional customer programmable electronic features to suit individual preferences.

Refer to ELECTRONIC VEHICLE INFORMATION CENTER PROGRAMMING in the Service Procedures section of this group for more information on the customer programmable feature options.

If the vehicle is equipped with the optional Universal Transmitter, the EVIC 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.

If the vehicle is equipped with the optional Tire Pressure Monitoring System, the EVIC will also display messages and an icon indicating when the tire air pressure falls below a given set-point, and which of the five tires is transmitting the low pressure warning, and when the condition is cleared. Refer to the Tires/Wheels section for complete Tire Pressure Monitoring System description. Refer to this section for EVIC modules function description for the Tire Pressure Monitoring.

NOTE: Some 300M vehicles use a different recommended tire pressure (tire specified). For this reason, anytime a EVIC module is removed or replaced a DRB III scan tool must be used to set/verify that the correct tire pressure set-point is programmed in the EVIC module. Failure to do so could result in incorrect tire pressure monitoring set points.

Data input for all EVIC functions, including VFD dimming level, is received through PCI data bus messages. The EVIC 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 tests as described in this group. If these tests prove inconclusive, the use of a DRB III scan tool and the proper Diagnostic Procedures are recommended for further testing of the EVIC module and the PCI data bus.

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

Compass
While in the compass/temperature mode, the compass will display the direction in which the vehicle is pointed using the eight major compass headings (Examples: north is N, northeast is NE). The self-calibrating compass unit requires no adjusting in normal use. The only calibration that may prove necessary is to drive the vehicle in three complete circles at 5 - 8 km/h (3 - 5 mph), on level ground, in not less than 48 seconds. This will reorient the compass unit to its vehicle.

The compass unit also will compensate for magnetism the body of the vehicle may acquire during normal use. However, avoid placing anything magnetic directly on the roof of the vehicle. Magnetic mounts for an antenna, a repair order hat, or a funeral procession flag can exceed the compensating ability of the compass unit if placed on the roof panel. Magnetic bit drivers used on the fasteners that hold the overhead console assembly to the roof header can also affect compass operation. If the vehicle roof should become magnetized, the demagnetizing and calibration procedures found in this group may be required to restore proper compass operation.

Temperature
The temperature displays the outside ambient temperature in whole degrees. The temperature display can be toggled from Fahrenheit to Celsius by selecting the desired U.S./Metric option from the customer programmable features as described in ELECTRONIC VEHICLE INFORMATION CENTER PROGRAMMING in the Service Procedures section of this group. The displayed temperature is not an instant reading of conditions, but an average temperature. It may take the thermometer display several minutes to respond to a major temperature change, such as driving out of a heated garage into winter temperatures.

When the ignition switch is turned to the OFF position, the last displayed temperature reading stays in the Body Control Module (BCM) unit memory When the ignition switch is turned to the ON position again, the EVIC will display the memory temperature for one minute; then update the display to the current average temperature reading within five minutes.

The temperature function is supported by an ambient temperature sensor. The sensor is mounted outside the passenger compartment near the front and center of the vehicle, and is hard wired to the Body Control Module (BCM). The BCM sends temperature status messages to the EVIC module over the PCI data bus network. The ambient temperature sensor is available as a separate service item.

The EVIC has access to both non-switched and ignition switched sources of battery current so that some of its features remain operational at any time, while others may only operate with the ignition switch in the ON position. When the ignition switch is turned to the ON position, the EVIC module VFD will return to the last function being displayed before the ignition was turned to the OFF position.

The compass/temperature display is the normal EVIC display With the ignition switch in the ON position, momentarily depressing and releasing the C/T (compass/temperature) push button switch will cause the EVIC to return to the compass/temperature/trip computer display mode from any other mode. While in the compass/temperature/trip computer display mode, momentarily depressing and releasing the Step push button will step through the available trip computer display options.

The EVIC trip computer features several functions that can be reset. The functions that can be reset are: average fuel economy, trip odometer and elapsed time. With the ignition switch in the ON position and with one of the functions of the trip computer that can be reset currently displayed, depressing the Reset push button twice within three seconds will perform a global reset, and all of the trip computer information that can be reset will be reset to zero. With the ignition switch in the ON position and the function that is to be reset currently displayed, momentarily depressing and releasing the Reset push button once will perform a local reset, and only the value of the displayed function will be reset to zero. A global or local reset will only occur if the function currently displayed is a function that can be reset. The distance to service function can also be reset using the local reset method, but it will reset back to the Service Interval distance that is set in the EVIC programmable features mode. Refer to ELECTRONIC VEHICLE INFORMATION CENTER PROGRAMMING in the Service Procedures section of this group for more information on setting the Service Interval.

For more information on the features, control functions and setting procedures for the EVIC module, see the owner's manual in the vehicle glove box.

UNIVERSAL TRANSMITTER
On some LFI models a Universal Transmitter is standard factory-installed equipment. The universal transmitter transceiver is integral to the Electronic Vehicle Information Center (EVIC), which is located in the overhead console. The only visible component of the universal transmitter are the three transmitter push buttons centered between the four EVIC push buttons located just rearward of the EVIC display screen in the overhead console. The three universal transmitter push buttons are identified with one, two or three light indicators so that they be easily identified by sight.

Each of the three universal transmitter push buttons controls an independent radio transmitter channel. Each of these three channels can be trained to transmit a different radio frequency signal for the remote operation of garage door openers, motorized gate openers, home or office lighting, security systems or just about any other device that can be equipped with a radio receiver in the 288 to 410 MegaHertz (MHz) frequency range for remote operation. The universal transmitter is capable of operating systems using either rolling code or non-rolling code technology.

The EVIC module displays messages and a small house-shaped icon with one, two or three dots corresponding to the three transmitter buttons to indicate the status of the universal transmitter. The EVIC messages are:
- Cleared Channels - Indicates that all of the transmitter codes stored in the universal transmitter have been successfully cleared.
- Training - Indicates that the universal transmitter is in its transmitter learning mode.
- Trained - Indicates that the universal transmitter has successfully acquired a new transmitter code.
- Transmit - Indicates that a trained universal transmitter button has been depressed and that the universal transmitter is transmitting.

The universal transmitter cannot be repaired, and is available for service only as a unit with the EVIC module. This unit includes the push button switches and the plastic module. If any of these components is faulty or damaged, the complete EVIC module must be replaced.

The universal transmitter operates on a non-switched source of battery current so the unit will remain functional, regardless of the ignition switch position. For more information on the features, programming procedures and operation of the universal transmitter, see the owner's manual in the vehicle glove box.

AMBIENT TEMP SENSOR
Ambient air temperature is monitored by the Electronic Vehicle Information Center (EVIC) through ambient temperature messages received from the Body Control Module (BCM) over the Programmable Communications Interface (PCI) data bus network. The BCM receives a hard wired input from the ambient temperature sensor. The ambient temperature sensor is a variable resistor mounted to a bracket that is secured with a screw to the right side of the headlamp mounting module grille opening, behind the radiator grille and in front of the engine compartment.

Refer to Body Control Module in Electronic Control Modules. For complete circuit diagrams, refer to the appropriate wiring information. The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The ambient temperature sensor is a variable resistor that operates on a five-volt reference signal sent to it by the BCM. The resistance in the sensor changes as temperature changes, changing the temperature sensor signal circuit voltage to the BCM. Based upon the resistance in the sensor, the BCM senses a specific voltage on the temperature sensor signal circuit, which it is programmed to correspond to a specific temperature. The BCM then sends the proper ambient temperature messages to the EVIC over the PCI data bus.

The thermometer function is supported by the ambient temperature sensor, a wiring circuit, the Body Control Module (BCM), the Programmable Communications Interface (PCI) data bus, and a portion of the Electronic Vehicle Information Center (EVIC) module. If any portion of the ambient temperature sensor circuit fails, the BCM will self-diagnose the circuit.

The ambient temperature sensor circuit can also be diagnosed by referring to Diagnosis and Testing - Ambient Temperature Sensor, and Diagnosis and Testing - Ambient Temperature Sensor Circuit. If the temperature sensor and circuit are confirmed to be OK, but the temperature display is inoperative or incorrect, refer to Diagnosis and Testing - Electronic Vehicle Information Center in this group. For complete circuit diagrams, refer to the appropriate wiring information.