Compass/Mini-Trip Computer Description; Operation; Diagnosis And Testing - Compass Mini-Trip Computer - Chrysler Concorde 2004 Service Manual

8M - 8 MESSAGE SYSTEMS
COMPASS/MINI-TRIP
COMPUTER
DESCRIPTION
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
• Trip Odometer
• Elapsed Time
• Miles to Service
• Tire Pressure Display (if equipped)
• Blank Screen
When the vehicle is first turned "ON" the Compass
Mini-Trip Computer blanks the display for a half sec-
ond, then Illuminates all segments of the vacuum
fluorescent display (VFD) at full brightness for one
and a half seconds. The Compass Mini-Trip Com-
puter module will then display whatever was being
viewed when the ignition was last turned "OFF".
Compass Mini-Trip Computer may also be inte-
grated with the Universal Transmitter. If so, your
Compass Mini-Trip Computer module will have three
buttons centered together between the outer four
buttons. Refer to the photo in Overhead Console
description.

OPERATION

The Compass Mini-Trip Computer (CMTC) and
push buttons will only operate when the ignition is
in the ON position. The CMTC will show the last dis-
play when the ignition was turned OFF. The four
buttons used to operate Compass Mini-Trip Com-
puter are labeled STEP, C/T, US/M and RESET.
STEP BUTTON
Pressing the STEP button selects one the following
4 displays:
• Average fuel economy
• Distance to empty
• Trip odometer
• Elapsed time
C/T (COMPASS/TEMPERATURE) BUTTON
Pressing the C/T button selects the current Com-
pass heading or current Temperature display.
US/M (ENGLISH/METRIC MEASUREMENT) BUTTON
Pressing the US/M button switches the display
units in English or Metric readings.
RESET BUTTON
Pressing the RESET button resets the function
currently on the display, provided that function can
be reset. The functions which can be reset are Aver-
age 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.
DIAGNOSIS AND TESTING - COMPASS
MINI-TRIP COMPUTER
TEMPERATURE
The Compass Mini-Trip Computer (CMTC) receives
Programmable Communications Interface bus (PCI
bus) messages from the Body Control Module for all
displayed information except the compass display. If
a dash (-) is displayed, the Compass Mini-Trip Com-
puter is not receiving a PCI bus message from the
BCM. To check out the PCI bus line and the BCM
use the DRB lll scan tool and proper Body Diagnos-
tic Procedure Manual.
If Compass Mini-Trip Computer displays a temper-
ature reading more than 54° C (130° F). Check for a
short circuit between the temperature sensor and the
BCM.
If Compass Mini-Trip Computer displays a temper-
ature reading less than -40° C (-67° F). Check for an
open circuit between the temperature sensor and the
BCM.
AVERAGE FUEL ECONOMY
Compass Mini-Trip Computer receives average fuel
economy information from the BCM over the PCI bus
line. If Compass Mini-Trip Computer displays -.-
instead of an average fuel economy value, it is not
receiving a PCI bus message for the average fuel
economy from the BCM. To check out the PCI bus
line and the BCM use the DRB lll scan tool.
DISTANCE TO EMPTY
Compass Mini-Trip Computer receives distance to
empty information from the BCM over the PCI bus
line. If Compass Mini-Trip Computer displays a dash
(-) instead of a distance to empty value, it is not
receiving a PCI bus message for the distance to
empty from the BCM. To check out the PCI bus line
and the BCM use the DRB lll scan tool.
LH