Computer JEEP GRAND CHEROKEE 2003 WJ / 2.G Workshop Manual

PROGRAMMABLE FEATURES
²LANGUAGE?-The options include English,
Francaise, Deutsch, Italiana, or Espanol. The default is
English. All EVIC display nomenclature, including the
trip computer functions, warning messages and the pro-
grammable features appear in the selected language.
²DISPLAY U.S. OR METRIC?- The options
include U.S. and M. The default is U.S. This feature
toggles the trip computer temperature, fuel economy
and odometer display readings between U.S. and
metric units of measure. It also changes the odome-
ter display in the instrument cluster.
²AUTO DOOR LOCKS?- The options include
Yes and No. The default is Yes. When Yes is selected,
all doors and the liftgate lock automatically when
vehicle speed reaches 25 kilometers-per-hour (15
miles-per-hour). If YES is selected, a second program-
mable feature appears,AUTO UNLOCK ON EXIT?
- The options again include Yes and No. The default
is No. When Yes is selected, following each Auto Door
Lock event all doors and the liftgate will automati-
cally unlock when the driver door is opened, if the
vehicle is stopped and the transmission gear selector
is in Park or Neutral. The Auto Door Unlock event
will only occur once following each Auto Door Lock
event.
²REMOTE UNLOCK- The options include
Driver Door 1st and All Doors. The default is Driver
Door 1st. When Diver Door 1st is selected, only the
driver door unlocks when the Unlock button of the
Remote Keyless Entry (RKE) transmitter is
depressed once. The Unlock button of the RKE trans-
mitter must be depressed twice to unlock all doors
and the liftgate. When All Doors is selected, all doors
and the liftgate unlock when the Unlock button of
the RKE transmitter is depressed once.
²REMOTE LINKED TO MEMORY?- This pro-
grammable feature only applies to vehicles equipped
with the optional memory system. The options
include Yes and No. The default is No. When Yes is
selected, the memory system will recall the Driver 1
or Driver 2 memory settings assigned to the RKE
transmitter being used to unlock the vehicle. When
No is selected, the memory system will only recall
memory settings when the Driver 1 or Driver 2 push
buttons of the memory switch on the driver side front
door trim panel are depressed.
²SOUND HORN ON LOCK?- The options
include Yes and No. The default is No. When Yes is
selected, a short horn chirp will provide an audible
confirmation when the RKE receiver recognizes a
valid Lock signal from an RKE transmitter. When No
is selected, no horn chirp will occur with the RKE
Lock event. This feature may be selected indepen-
dent of theFLASH LIGHTS WITH LOCKS?pro-
grammable feature.²FLASH LIGHTS WITH LOCKS?- The options
include Yes and No. The default is Yes. When Yes is
selected, a single flash of the hazard warning lamps
will provide an optical confirmation when the RKE
receiver recognizes a valid Lock signal from an RKE
transmitter, and two flashes of the same lamps will
occur when the RKE receiver recognizes a valid
Unlock signal from an RKE transmitter. When No is
selected, no lamp flash will occur with the RKE Lock
or Unlock event. This feature may be selected inde-
pendent of theSOUND HORN ON LOCK?pro-
grammable feature.
²HEADLAMP DELAY =- The options include
Off, 30 Sec, 60 Sec, and 90 Sec. The default is 90 Sec.
When a time interval is selected, the headlamps will
remain on for that length of time when the head-
lamps are turned off after the ignition is turned off,
or if the Auto mode is selected on vehicles with the
Auto Headlamps option. When Off is selected, the
headlamp delay feature is disabled.
²HEADLAMPS ON WITH WIPERS?- This pro-
grammable feature only applies to vehicles equipped
with the optional Auto Headlamps. The options
include Yes and No. The default is No. When Yes is
selected, the headlamps will turn on automatically
when the windshield wipers are turned on. The head-
lamps will turn off when the wipers are turned off,
as long as the headlamp switch is in the Auto or Off
positions. When No is selected, the headlamps will
only turn on if manually selected or if the Auto mode
is selected and the outside ambient light levels dic-
tate that they should be on.
²SERVICE INTV. =- The options include from
1000 to 12000 kilometers in 1000 kilometer incre-
ments (2000 to 7500 miles in 500 mile increments).
The default is 12000 kilometers (7500 miles). The
selected distance becomes the interval at which the
Perform Service warning message will be displayed
by the EVIC. If a new distance is selected, a second
programmable feature appears,RESET SERVICE
DISTANCE?- The options include No and Yes. The
default is Yes. When Yes is selected, the accumulated
distance since the last previous Perform Service
warning message will be reset to zero because the
service interval has been changed. When No is
selected, the distance until the next Perform Service
warning message is reduced by the accumulated dis-
tance since the last previous message.
²LOW FUEL CHIME?- The options include Yes
and No. The default is Yes. When Yes is selected, a
single chime will sound as an audible alert whenever
the instrument cluster low fuel warning lamp lights.
The chime will sound only once per ignition cycle.
When No is selected, only the low fuel warning lamp
in the instrument cluster will light and no chime will
sound.
WJMESSAGE SYSTEMS 8M - 3
OVERHEAD CONSOLE (Continued)

for door and liftgate open indications and to show if a
turn signal has been left on. The EVIC messages and
displays are coordinated with warning indicators in
the instrument cluster to avoid duplication.
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 capabil-
ities.
The EVIC module includes the following display
options:
²Compass and Temperature- provides the out-
side temperature and one of eight compass readings
to indicate the direction the vehicle is facing.
²Average fuel economy- shows the average
fuel economy since the last trip computer reset.
²Distance to empty- shows the estimated dis-
tance 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.
²Instant fuel economy- shows the present fuel
economy based upon the current vehicle distance and
fuel used information.
²Trip distance- shows the distance travelled
since the last trip computer reset.
²Elapsed time- shows the accumulated igni-
tion-on time since the last trip computer reset.
²Distance to service- shows the distance
remaining until the next scheduled service interval.
²Tire Pressure- shows the tire pressure in each
tire.
²Blank screen- the EVIC compass/temperature/
trip computer VFD is turned off.
The EVIC is capable of displaying the following
alert messages, which are accompanied by an audible
announcement consisting of a series of beeps:
²TURN SIGNALS ON (with vehicle graphic)-
Indicates that a turn signal has remained on for
about 1.6 kilometers (one mile).
²PERFORM SERVICE- Indicates that a cus-
tomer programmable service interval distance has
been reached.
²DOOR OPEN (one or more, with vehicle
graphic)- Indicates that a door is open or not fully
closed.
²LIFTGATE OPEN (with vehicle graphic)-
Indicates that the liftgate is open or not fully closed.
²LIFTGLASS OPEN (with vehicle graphic)-
Indicates that the liftglass is open or not fully closed.²COOLANT LEVEL LOW (with vehicle
graphic)- Indicates that the coolant level in the
engine coolant reservoir is low.
²XX LOW PRESSURE (with vehicle graphic)
- Indicates that the air pressure in the selected tire
is low.
²WASHER FLUID LOW (with vehicle
graphic)- Indicates that the fluid level in the
washer fluid reservoir is low.
The EVIC ªMenuº 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 toELECTRONIC VEHICLE INFORMA-
TION CENTER PROGRAMMINGin the Service
Procedures section of this group for more information
on the customer programmable feature options.
If the vehicle is equipped with the optional mem-
ory system, the EVIC will display the following mem-
ory system messages:
²MEMORY #X POSITION SET (X = Driver 1
or Driver 2)- This message appears in the EVIC
display each time the memory system is successfully
programmed. It is accompanied by an audible
announcement chime tone.
²MEMORY SYSTEM DISABLED- The memory
system is automatically disabled while the driver
side seat belt is fastened and/or while the automatic
transmission gear selector is in any position except
Park or Neutral. This message appears in the EVIC
display as a reminder when a memory switch push
button is depressed while the memory system is dis-
abled. If the REMOTE LINKED TO MEMORY cus-
tomer programmable feature has been selected, this
message will also appear when the Unlock button of
the Remote Keyless Entry (RKE) transmitter is
depressed while the memory system is disabled.
If the vehicle is equipped with the optional Univer-
sal Transmitter transceiver, the EVIC will also dis-
play 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 optionalTire
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 pres-
sure warning, and when the condition is cleared.
Refer to the Tires/Wheels section of this manual for
complete Tire Pressure Monitoring System descrip-
tion. Refer to this section of the service manual for
EVIC modules function description for the Tire Pres-
sure Monitoring.
Data input for all EVIC functions, including VFD
dimming level, is received through PCI data bus
WJMESSAGE SYSTEMS 8M - 7
ELECTRONIC VEHICLE INFO CENTER (Continued)

OPERATION
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/tempera-
ture/trip computer display mode from any other
mode. While in the compass/temperature/trip com-
puter 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 CEN-
TER PROGRAMMINGin the Service Procedures
section of this group for more information on setting
the Service Interval.
For more information on the features, control func-
tions and setting procedures for the EVIC module,
see the owner's manual in the vehicle glove box.
DIAGNOSIS AND TESTING - ELECTRONIC
VEHICLE INFORMATION CENTER
If the problem with the Electronic Vehicle Informa-
tion Center (EVIC) is a temperature reading of 130É
F or -40ÉF shown in the compass/temperature dis-
play, refer toAmbient Temperature Sensor Diag-
nosis and Testingin this group. If the problem with
the EVIC is an inaccurate or scrambled display, refer
toSelf-Diagnostic Testin this group. If the prob-lem with the EVIC is incorrect Vacuum Fluorescent
Display (VFD) dimming levels, use a DRBtscan tool
and the proper Diagnostic Procedures manual to test
for the correct dimming message inputs being
received from the Body Control Module (BCM) over
the Programmable Communications Interface (PCI)
data bus. If the problem is a no-display condition,
use the following procedures. For complete circuit
diagrams, refer toOverhead Consolein Wiring
Diagrams.
(1) Check the fused B(+) fuse in the junction block.
If OK, go to Step 2. If not OK, repair the shorted cir-
cuit or component as required and replace the faulty
fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the junction block. If OK, go to Step 3. If not OK,
repair the open fused B(+) circuit to the fused B(+)
fuse in the PDC as required.
(3) Check the fused ignition switch output (run/
start) fuse in the junction block. If OK, go to Step 4.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the junction block. If OK,
go to Step 5. If not OK, repair the open fused ignition
switch output (run/start) circuit to the ignition switch
as required.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the overhead console. Check for continuity
between the ground circuit cavity of the roof wire
harness connector for the EVIC module and a good
ground. There should be continuity. If OK, go to Step
6. If not OK, repair the open ground circuit to ground
as required.
(6) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
roof wire harness connector for the EVIC module. If
OK, go to Step 7. If not OK, repair the open fused
B(+) circuit to the fused B(+) fuse in the junction
block as required.
(7) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) circuit cavity of the roof wire har-
ness connector for the EVIC module. If OK, refer to
Self-Diagnostic Testbelow for further diagnosis of
the EVIC module and the PCI data bus. If not OK,
repair the open fused ignition switch output (run/
start) circuit to the fuse in the junction block as
required.
SELF-DIAGNOSTIC TEST
A self-diagnostic test is used to determine that the
EVIC module is operating properly, and that all PCI
WJMESSAGE SYSTEMS 8M - 9
ELECTRONIC VEHICLE INFO CENTER (Continued)

data bus messages are being received for initial oper-
ation. Initiate the self-diagnostic test as follows:
(1) With the ignition switch in the Off position,
simultaneously depress and hold the C/T button and
the Reset button.
(2) Turn the ignition switch to the On position.
(3) Continue to hold both buttons depressed until
the EVIC software version information is displayed,
then release both buttons.
(4) Following completion of these tests, the EVIC
module will display one of the following messages:
a.Pass Self Test- Momentarily depress and
release the Reset button to return to the compass/
temperature/trip computer display mode. The EVIC
module is working properly.
b.Failed Self Test- The EVIC module has an
internal failure. The EVIC module is faulty and must
be replaced.
c.Not Receiving J1850 Message- The EVIC
module is not receiving proper message input
through the PCI data bus. This can result from one
or more faulty electronic modules in the vehicle, or
from a faulty PCI data bus. The use of a DRB scan
tool and the proper Diagnostic Procedures manual
are required for further diagnosis.
NOTE: If the compass functions, but accuracy is
suspect, it may be necessary to perform a variation
adjustment. This procedure allows the compass
unit to accommodate variations in the earth's mag-
netic field strength, based on geographic location.
Refer to Compass Variation Adjustment in the Stan-
dard Procedures section of this group.
NOTE: If the compass reading displays a blank, and
only ªCALº appears in the display, demagnetizing
may be necessary to remove excessive residual
magnetic fields from the vehicle. Refer to Compass
Demagnetizing in the Standard Procedures section
of this group.
STANDARD PROCEDURE - TIRE PRESSURE
SYSTEM TEST
The following test can be used to verify two func-
tions. One, that the tire pressure sensors are trans-
mitting properly and two, the EVIC module is
receiving these transmissions accordingly.
(1) Retrain the tire sensors (Refer to 22 - TIRES/
WHEELS/TIRE PRESSURE MONITORING/SEN-
SOR - STANDARD PROCEDURE). The tire sensors
must be retrained in order to set the proper trans-
mitting time cycle (twice a minute), failure to retrain
the sensors will cause a much slower transmitting
time cycle (once a hour).(2) Using the STEP button on the overhead con-
sole, scroll to the blank display, then press the
RESET button for five seconds, a beep will sound
indicating the start of this test. The vehicle icon and
transmission counters will now be displayed, (same
display as individual tire pressure except counters
replace tire pressure values).
(3) Upon entering the test mode, the EVIC will
clear the sensor counter and each time a sensor sig-
nal for a road tire is received, the EVIC will update
the counter value (vehicle must be driven at 25 mph
to transmit). The counter values should all read the
same value. If any of the road tires indicate a differ-
ent value than another tire sensor, this is a sign of a
problem. Replace the appropriate tire sensor and
retest the system. This test will continue until any of
the overhead console buttons are pressed or the igni-
tion is turned off.
NOTE: Pressing the RESET button during the test
will sound a beep and reset all the counter values
back to zero.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the overhead console from the head-
liner (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE - REMOVAL).
(3) Remove the four screws that secure the Elec-
tronic Vehicle Information Center (EVIC) module to
the overhead console housing (Fig. 5).
(4) Remove the EVIC module from the overhead
console housing.
INSTALLATION
(1) Position the EVIC module onto the overhead
console housing.
(2) Install and tighten the four screws that secure
the EVIC module to the overhead console housing.
Tighten the screws to 0.9 N´m (8 in. lbs.).
(3) Install the overhead console onto the headliner
(Refer to 8 - ELECTRICAL/OVERHEAD CONSOLE -
INSTALLATION).
(4) Reconnect the battery negative cable.
NOTE: If a new EVIC module has been installed, the
compass will have to be calibrated and the variance
set. Refer to Compass Variation Adjustment and
Compass Calibration in the Service Procedures sec-
tion of this group for the procedures.
8M - 10 MESSAGE SYSTEMSWJ
ELECTRONIC VEHICLE INFO CENTER (Continued)

Check the vapor/vacuum lines at the LDP, LDP
filter and EVAP canister purge solenoid for
damage or leaks. If a leak is present, a Diagnos-
tic Trouble Code (DTC) may be set.
(2) Connect electrical connector to LDP.
(3) While raising front section of support bracket,
connect LDP wiring clip (Fig. 20).
(4) Install 3 LDP mounting bolts (Fig. 19). Refer to
Torque Specifications.
(5) Join front and rear sections of two-piece sup-
port bracket by installing 3 bolts on bottom of sup-
port bracket (Fig. 17). Do not tighten bolts at this
time.
(6) Install support bracket brace bolt (Fig. 17). Do
not tighten bolt at this time.
(7) Tighten 2 support bracket nuts at frame rail
(Fig. 19). Refer to Torque Specifications.
(8) Tighten 3 support bracket bolts and brace bolt.
Refer to Torque Specifications.
(9) Position stone shield behind left/rear wheel
(Fig. 18). Install new plastic rivets.
ORVR
DESCRIPTION
The ORVR (On-Board Refueling Vapor Recovery)
system consists of a unique fuel tank, flow manage-
ment valve, fluid control valve, one-way check valve
and vapor canister. Certain ORVR components can be
found in (Fig. 1).
OPERATION
The ORVR (On-Board Refueling Vapor Recovery)
system is used to remove excess fuel tank vapors.
This is done while the vehicle is being refueled. Cer-
tain ORVR components can be found in (Fig. 1).
Fuel flowing into the fuel filler tube (approx. 1º
I.D.) creates an aspiration effect drawing air into the
fuel fill tube. During refueling, the fuel tank is
vented to the EVAP canister to capture escaping
vapors. With air flowing into the filler tube, there are
no fuel vapors escaping to the atmosphere. Once the
refueling vapors are captured by the EVAP canister,
the vehicle's computer controlled purge system draws
vapor out of the canister for the engine to burn. The
vapor flow is metered by the purge solenoid so that
there is no, or minimal impact on driveability or
tailpipe emissions.As fuel starts to flow through the fuel fill tube, it
opens the normally closed check valve and enters the
fuel tank. Vapor or air is expelled from the tank
through the control valve and on to the vapor canis-
ter. Vapor is absorbed in the EVAP canister until
vapor flow in the lines stops. This stoppage occurs
following fuel shut-off, or by having the fuel level in
the tank rise high enough to close the control valve.
This control valve contains a float that rises to seal
the large diameter vent path to the EVAP canister.
At this point in the refueling process, fuel tank pres-
sure increases, the check valve closes (preventing liq-
uid fuel from spiting back at the operator), and fuel
then rises up the fuel filler tube to shut off the dis-
pensing nozzle.
PCV VALVE
DIAGNOSIS AND TESTING - PCV VALVE/PCV
SYSTEM - 4.7L
(1) Disconnect PCV line/hose (Fig. 21) by discon-
necting rubber connecting hose at PCV valve fitting.
(2) Remove PCV valve at oil filler tube by rotating
PCV valve downward until locating tabs have been
freed at cam lock (Fig. 21). After tabs have cleared,
pull valve straight out from filler tube.To prevent
damage to PCV valve locating tabs, valve must
be pointed downward for removal. Do not force
valve from oil filler tube.
(3) After valve is removed, check condition of valve
o-ring (Fig. 21). Also, PCV valve should rattle when
shaken.
(4) Reconnect PCV valve to its connecting line/
hose.
(5) Start engine and bring to idle speed.
(6) If valve is not plugged, a hissing noise will be
heard as air passes through valve. Also, a strong vac-
uum should be felt with a finger placed at valve
inlet.
(7) If vacuum is not felt at valve inlet, check line/
hose for kinks or for obstruction. If necessary, clean
out intake manifold fitting at rear of manifold. Do
this by turning a 1/4 inch drill (by hand) through the
fitting to dislodge any solid particles. Blow out the
fitting with shop air. If necessary, use a smaller drill
to avoid removing any metal from the fitting.
WJEVAPORATIVE EMISSIONS 25 - 37
LEAK DETECTION PUMP (Continued)