2003 JEEP GRAND CHEROKEE Stored codes

The spring type hose clamp applies constant ten-
sion on a hose connection. To remove a spring type
hose clamp, only use constant tension clamp pliers
designed to compress the hose clamp.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTINGÐON-BOARD
DIAGNOSTICS (OBD)
COOLING SYSTEM RELATED DIAGNOSTICS
The powertrain control module (PCM) has been
programmed to monitor certain cooling system com-
ponents:
²If the engine has remained cool for too long a
period, such as with a stuck open thermostat, a Diag-
nostic Trouble Code (DTC) can be set.
²If an open or shorted condition has developed in
the relay circuit controlling the electric radiator fan
or fan control solenoid circuit controling the hydrau-
lic fan, a Diagnostic Trouble Code (DTC) can be set.
If the problem is sensed in a monitored circuit
often enough to indicated an actual problem, a DTC
is stored. The DTC will be stored in the PCM mem-
ory for eventual display to the service technician.
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ACCESSING DIAGNOSTIC TROUBLE CODES
To read DTC's and to obtain cooling system data,
(Refer to 25 - EMISSIONS CONTROL - DESCRIP-
TION).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB
scan tool to erase a DTC. Refer to the appropriate
Powertrain Diagnostic Procedures service informa-
tion for operation of the DRB scan tool.
DIAGNOSIS AND TESTINGÐPRELIMINARY
CHECKS
ENGINE COOLING SYSTEM OVERHEATING
Establish what driving conditions caused the com-
plaint. Abnormal loads on the cooling system such as
the following may be the cause:
²PROLONGED IDLE
²VERY HIGH AMBIENT TEMPERATURE
Fig. 2 Cooling Module with Electric Fan
1 - RADIATOR
2 - ELECTRIC COOLING FAN CONNECTOR
3 - FAN SHROUD
4 - ELECTRIC COOLING FAN
Fig. 3 Engine Cooling SystemÐ4.0L EngineÐ
Typical
1 - HEATER CORE
2 - TO COOLANT RESERVE/OVERFLOW TANK
3 - THERMOSTAT HOUSING
4 - RADIATOR
5 - WATER PUMP
WJCOOLING 7 - 3
COOLING (Continued)

sponder through a tuned antenna ring integral to the
SKIM housing. If this antenna ring is not mounted
properly around the ignition lock cylinder housing,
communication problems between the SKIM and the
transponder may arise. These communication prob-
lems will result in Sentry Key transponder-related
faults. The SKIM also communicates over the Pro-
grammable Communications Interface (PCI) data bus
with the Powertrain Control Module (PCM), the Elec-
troMechanical Instrument Cluster (EMIC), the Body
Control Module (BCM), and/or the DRBIIItscan tool.
The SKIM retains in memory the ID numbers of
any Sentry Key transponder that is programmed into
it. A maximum of eight transponders can be pro-
grammed into the SKIM. For added system security,
each SKIM is programmed with a unique Secret Key
code. This code is stored in memory, sent over the
PCI data bus to the PCM, and is encoded to the tran-
sponder of every Sentry Key that is programmed into
the SKIM. Another security code, called a PIN, is
used to gain access to the SKIM Secured Access
Mode. The Secured Access Mode is required during
service to perform the SKIS initialization and Sentry
Key transponder programming procedures. The
SKIM also stores the Vehicle Identification Number
(VIN) in its memory, which it learns through a PCI
data bus message from the PCM during SKIS initial-
ization.
In the event that a SKIM replacement is required,
the Secret Key code can be transferred to the new
SKIM from the PCM using the DRBIIItscan tool
and the SKIS replacement procedure. Proper comple-
tion of the SKIS initialization will allow the existing
Sentry Keys to be programmed into the new SKIM so
that new keys will not be required. In the event that
the original Secret Key code cannot be recovered,
SKIM replacement will also require new Sentry
Keys. The DRBIIItscan tool will alert the technician
during the SKIS replacement procedure if new Sen-
try Keys are required.
When the ignition switch is turned to the On posi-
tion, the SKIM transmits an RF signal to the tran-
sponder in the ignition key. The SKIM then waits for
an RF signal response from the transponder. If the
response received identifies the key as valid, the
SKIM sends a valid key message to the PCM over
the PCI data bus. If the response received identifies
the key as invalid, or if no response is received from
the key transponder, the SKIM sends an invalid key
message to the PCM. The PCM will enable or disable
engine operation based upon the status of the SKIM
messages. It is important to note that the default
condition in the PCM is an invalid key; therefore, if
no message is received from the SKIM by the PCM,
the engine will be disabled and the vehicle immobi-
lized after two seconds of running.The SKIM also sends indicator light status mes-
sages to the EMIC over the PCI data bus to tell the
EMIC how to operate the SKIS indicator. This indi-
cator light status message tells the EMIC to turn the
indicator on for about three seconds each time the
ignition switch is turned to the On position as a bulb
test. After completion of the bulb test, the SKIM
sends indicator light status messages to the EMIC to
turn the indicator off, turn the indicator on, or to
flash the indicator on and off. If the SKIS indicator
lamp flashes or stays on solid after the bulb test, it
signifies a SKIS fault. If the SKIM detects a system
malfunction and/or the SKIS has become inoperative,
the SKIS indicator will stay on solid. If the SKIM
detects an invalid key or if a key transponder-related
fault exists, the SKIS indicator will flash. If the vehi-
cle is equipped with the Customer Learn transponder
programming feature, the SKIM will also send mes-
sages to the EMIC to flash the SKIS indicator lamp,
and to the BCM to generate a single audible chime
tone whenever the Customer Learn programming
mode is being utilized. (Refer to 8 - ELECTRICAL/
VEHICLE THEFT SECURITY - STANDARD PRO-
CEDURE - SENTRY KEY TRANSPONDER
PROGRAMMING).
The SKIS performs a self-test each time the igni-
tion switch is turned to the On position, and will
store fault information in the form of Diagnostic
Trouble Codes (DTC's) in SKIM memory if a system
malfunction is detected. The SKIM can be diagnosed,
and any stored DTC's can be retrieved using a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the steering column opening cover
from the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/STEERING COLUMN OPEN-
ING COVER - REMOVAL).
8E - 18 ELECTRONIC CONTROL MODULESWJ
SENTRY KEY IMMOBILIZER MODULE (Continued)

NOTE: If the vehicle is equipped with the Tire Pres-
sure Monitoring (TPM) System, and the overhead
console electronics module is removed or replaced,
the TPM system will need to be retrained. Refer to
the Tires/Wheels section of this manual for the pro-
cedure.
UNIVERSAL TRANSMITTER
DESCRIPTION
The Grand Cherokee Limited model has a Univer-
sal Garage Door Opener (UGDO) transceiver as stan-
dard factory-installed equipment. The UGDO is
optional on Laredo models. The UGDO transceiver is
integral to the Electronic Vehicle Information Center
(EVIC), which is located in the overhead console. The
only visible component of the UGDO 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 UGDO transmitter push buttons are identified
with one, two or three dots so that they be easily
identified by sight.
Each of the three UGDO transmitter push buttons
controls an independent radio transmitter channel.
Each of these three channels can be trained to trans-
mit a different radio frequency signal for the remoteoperation 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
UGDO 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 corre-
sponding to the three transmitter buttons to indicate
the status of the UGDO. The EVIC messages are:
²Cleared Channels- Indicates that all of the
transmitter codes stored in the UGDO have been suc-
cessfully cleared.
²Training- Indicates that the UGDO is in its
transmitter learning mode.
²Trained- Indicates that the UGDO has success-
fully acquired a new transmitter code.
²Transmit- Indicates that a trained UGDO
transmitter button has been depressed and that the
UGDO is transmitting.
The UGDO 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 plas-
tic module. If any of these components are faulty or
damaged, the complete EVIC module must be
replaced.
OPERATION
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, pro-
gramming procedures and operation of the universal
transmitter, see the owner's manual in the vehicle
glove box.
DIAGNOSIS AND TESTING - UNIVERSAL
TRANSMITTER
If the Universal Transmitter is inoperative, but the
Electronic Vehicle Information Center (EVIC) is oper-
ating normally, see the owner's manual in the vehicle
glove box for instructions on training the Transmit-
ter. Retrain the Transmitter with a known good
transmitter as instructed in the owner's manual and
test the Transmitter operation again. If the unit is
still inoperative, replace the faulty Transmitter and
EVIC module as a unit. If both the Transmitter and
the EVIC module are inoperative, refer toElec-
tronic Vehicle Information Center Diagnosis
and Testingin this group for further diagnosis. For
complete circuit diagrams, refer toWiring Dia-
grams.
Fig. 5 Top of Overhead Console
1 - OVERHEAD CONSOLE HOUSING
2 - EVIC MODULE
3 - ILLUMINATION LAMPS
4 - SCREWS (4)
WJMESSAGE SYSTEMS 8M - 11
ELECTRONIC VEHICLE INFO CENTER (Continued)

The RKE system includes two transmitters when
the vehicle is shipped from the factory, but the sys-
tem can retain the vehicle access codes of up to four
transmitters. The transmitter codes are retained in
the RKE receiver memory, even if the battery is dis-
connected. If an RKE transmitter is faulty or lost,
new transmitter vehicle access codes can be pro-
grammed into the system using a DRBIIItscan tool
and the appropriate diagnostic information.
This vehicle also offers several customer program-
mable features, which allows the selection of several
optional electronic features to suit individual prefer-
ences. (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE/ELECTRONIC VEHICLE INFO CENTER -
DESCRIPTION). Customer programmable feature
options affecting the RKE system include:
²Remote Unlock- Allows the option of having
only the driver side front door unlock when the RKE
transmitter Unlock button is depressed the first time
and the remaining doors and the liftgate unlock
when the button is depressed a second time, or hav-
ing all doors and the liftgate unlock upon the first
depression of the RKE transmitter Unlock button.
²Remote Linked to Memory- If the vehicle is
equipped with the Memory System, this feature
allows the option of having the RKE transmitter
Unlock button activate the recall of the stored set-
tings, or having the recall function assigned solely to
the memory switch on the driver side front door trim
panel.
²Sound Horn on Lock- Allows the option of
having the horn sound a short chirp as an audible
verification that the doors have locked, or having no
audible verification.
²Flash Lights with Lock- Allows the option of
having the lights flash as an optical verification that
the doors have locked, or having no optical verifica-
tion.
This group covers the following components of the
RKE system:
²RKE Receiver
²RKE Transmitter
Certain functions and features of the RKE system
rely upon resources shared with other electronic
modules in the vehicle over the Programmable Com-
munications Interface (PCI) data bus network. The
PCI data bus network allows the sharing of sensor
information. This helps to reduce wire harness com-
plexity, internal controller hardware, and 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. For diagnosis of these electronic modules or of
the PCI data bus network, the use of a DRBIIItscan
tool and the appropriate diagnostic information are
required.The other electronic modules that may affect RKE
system operation are as follows:
²Body Control Module (BCM)- (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/BODY CONTROL/CENTRAL TIMER MOD-
ULE - DESCRIPTION).
²Driver Door Module (DDM)- (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/DOOR MODULE - DESCRIPTION).
²Electronic Vehicle Information Center
(EVIC)- (Refer to 8 - ELECTRICAL/OVERHEAD
CONSOLE/ELECTRONIC VEHICLE INFO CENTER
- DESCRIPTION).
²Passenger Door Module (PDM)- (Refer to 8 -
ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/DOOR MODULE - DESCRIPTION).
²Powertrain Control Module (PCM)- (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL
MODULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION).
Hard wired circuitry connects the RKE system
components via the PDM to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the RKE system com-
ponents through the use of a combination of soldered
splices, splice block connectors, and many different
types of wire harness terminal connectors and insu-
lators. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, further
details on wire harness routing and retention, as well
as pin-out and location views for the various wire
harness connectors, splices and grounds.
COMBINATION FLASHER
The combination flasher is a smart relay that func-
tions as both the turn signal system and the hazard
warning system flasher. The combination flasher con-
tains active electronic Integrated Circuitry (IC) ele-
ments. This flasher can be energized by the BCM to
flash all of the park/turn signal/front side marker
lamps as an optical alert for the RKE panic function
and, if the Flash Lights with Lock programmable fea-
ture is enabled, as an optical verification for the RKE
lock event. (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/COMBINATION FLASHER
- DESCRIPTION).
HORN RELAY
The horn relay is a electromechanical device that
switches battery current to the horn when the horn
switch grounds the relay coil. The horn relay is
located in the Power Distribution Center (PDC) in
WJPOWER LOCKS 8N - 3
POWER LOCKS (Continued)

following procedure should be performed using a
DRBIIItscan tool to verify the status of both airbag
squibs before either deployed airbag is removed from
the vehicle for disposal.
CAUTION: Deployed front airbags having two initia-
tors (squibs) in the airbag inflator may or may not
have live pyrotechnic material within the inflator. Do
not dispose of these airbags unless you are sure of
complete deployment. Refer to the Hazardous Sub-
stance Control System for proper disposal proce-
dures. Dispose of all non-deployed and deployed
airbags in a manner consistent with state, provin-
cial, local, and federal regulations.(1) Be certain that the DRBIIItscan tool contains
the latest version of the proper DRBIIItsoftware.
Connect the DRBIIItto the 16-way Data Link Con-
nector (DLC). The DLC is located on the driver side
lower edge of the instrument panel, outboard of the
steering column.
(2) Turn the ignition switch to the On position.
(3) Using the DRBIIIt, read and record the active
(current) Diagnostic Trouble Code (DTC) data.
Using the active DTC information, refer to theAir-
bag Squib Statustable to determine the status of
both driver and/or passenger airbag squibs.
AIRBAG SQUIB STATUS
IF the Active DTC is: Conditions Squib Status
Driver or Passenger Squib 1
openANDthe stored DTC minutes for both Driver
or Passenger squibs are within 15 minutes of
each otherBoth Squib 1 and 2 were
used.
Driver or Passenger Squib 2
open
Driver or Passenger Squib 1
openANDthe stored DTC minutes for Driver or
Passenger Squib 2 open is GREATER than the
stored DTC minutes for Driver or Passenger
Squib 1 by 15 minutes or moreSquib 1 was used; Squib 2 is
live.
Driver or Passenger Squib 2
open
Driver or Passenger Squib 1
openANDthe stored DTC minutes for Driver or
Passenger Squib 1 open is GREATER than the
stored DTC minutes for Driver or Passenger
Squib 2 by 15 minutes or moreSquib 1 is live; Squib 2 was
used.
Driver or Passenger Squib 2
open
Driver or Passenger Squib 1
openANDDriver or Passenger Squib 2 open is NOT
an active codeSquib 1 was used; Squib 2 is
live.
Driver or Passenger Squib 2
openANDDriver or Passenger Squib 1 open is NOT
an active codeSquib 1 is live; Squib 2 was
used.
Ifnone of the Driver or Passenger Squib 1 or 2
open are active codes, the status of the airbag squibs
is unknown. In this case the airbag should be han-
dled and disposed of as if the squibs were both live.
CLEANUP PROCEDURE
Following a supplemental restraint deployment,
the vehicle interior will contain a powdery residue.
This residue consists primarily of harmless particu-
late by-products of the small pyrotechnic charge that
initiates the propellant used to deploy a supplemen-
tal restraint. However, this residue may also contain
traces of sodium hydroxide powder, a chemical
by-product of the propellant material that is used to
generate the inert gas that inflates the airbag. Since
sodium hydroxide powder can irritate the skin, eyes,
nose, or throat, be sure to wear safety glasses, rubber
gloves, and a long-sleeved shirt during cleanup (Fig.
3).
Fig. 3 Wear Safety Glasses and Rubber Gloves -
Typical
WJRESTRAINTS 8O - 7
RESTRAINTS (Continued)

The ITM microprocessor continuously monitors
inputs from its on-board motion sensor as well as
inputs from the BCM and the alarm siren module.
The ITM motion sensor transmits ultrasonic signals
into the vehicle cabin through a transmit transducer,
then listens to the returning signals as the bounce off
of objects in the vehicle interior. If an object is mov-
ing in the interior, a detection circuit in the ITM
senses this movement through the modulation of the
returning ultrasonic signals that occurs due to the
Doppler effect. The motion detect function of the ITM
can be disabled by depressing the ªLockº button on
the Remote Keyless Entry (RKE) transmitter three
times within fifteen seconds, while the security indi-
cator is still flashing rapidly or by cycling the key in
the driver door cylinder from the center to the lock
position. The ITM will signal the alarm siren module
to provide a single siren ªchirpº as an audible confir-
mation that the motion sensor function has been dis-
abled.
If movement is detected, the ITM sends an mes-
sage to the BCM over the PCI data bus to flash the
exterior lighting and send a message to the alarm
siren module over a dedicated serial bus line to
sound the siren. When the BCM detects a breach in
the perimeter protection through a door, tailgate,
flip-up glass, or hood ajar switch input, it sends an
message to the ITM and the ITM sends an message
to the BCM over the PCI data bus to flash the exte-
rior lighting and send a message to the alarm siren
module over a dedicated serial bus line to sound the
siren. The ITM also monitors inputs from the alarm
siren module for siren battery or siren input/output
circuit tamper alerts, and siren battery condition
alerts, then sets active and stored Diagnostic Trouble
Codes (DTC) for any monitored system faults it
detects. An active fault only remains for the current
ignition switch cycle, while a stored fault causes a
DTC to be stored in memory by the ITM. If a fault
does not reoccur for fifty ignition cycles, the ITM will
automatically erase the stored DTC.
The ITM is connected to the vehicle electrical sys-
tem through the overhead wire harness. The ITM
receives battery voltage on a B(+) circuit through a
fuse in the Junction Block (JB), and is grounded to
the chassis at G303. These connections allow the
ITM to remain operational, regardless of the ignition
switch position. The hard wired inputs and outputs
for the ITM may be diagnosed and tested using con-
ventional diagnostic tools and procedures. However,
conventional diagnostic methods will not prove con-
clusive in the diagnosis of the ITM, the PCI data bus
network, or the electronic message inputs to and out-
puts from the ITM. The most reliable, efficient, and
accurate means to diagnose the ITM, the PCI data
bus network, and the message inputs to and outputsfrom the ITM requires the use of a DRBIIItscan
tool. Refer to the appropriate diagnostic information.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) While pulling downward lightly on the rear cor-
ner of the Intrusion Transceiver Module (ITM) trim
cover, insert a small thin-bladed screwdriver through
each of the service holes on the rear edge of the trim
cover to release the two integral rear latch features
of the module from the mounting bracket above the
headliner (Fig. 7).
(3) Pull the ITM trim cover rearward far enough
to disengage the two front latch features of the mod-
ule from the mounting bracket above the headliner.
(4) Pull the ITM and trim cover down from the
headliner far enough to access and disconnect the
overhead wire harness connector for the ITM from
the module connector.
(5) Remove the ITM from the headliner.
INSTALLATION
(1) Position the Intrusion Transceiver Module
(ITM) to the headliner.
(2) Reconnect the overhead wire harness connector
for the ITM to the module connector.
(3) Align the two front latch features of the ITM
with the two front latch receptacles of the mounting
bracket above the headliner (Fig. 8).
(4) Push the ITM trim cover forward far enough to
insert the two rear latch features of the module into
Fig. 7 INTRUSION TRANSCEIVER MODULE
REMOVE
1 - SMALL SCREWDRIVER
2 - HEADLINER
3 - SERVICE HOLES
4 - ITM
8Q - 12 VEHICLE THEFT SECURITYWJ
INTRUSION TRANSCEIVER MODULE (Continued)

STANDARD PROCEDURE - FUEL SYSTEM
PRESSURE RELEASE
Use following procedure if the fuel injector
rail is, or is not equipped with a fuel pressure
test port.
(1) Remove fuel fill cap.
(2) Remove fuel pump relay from Power Distribu-
tion Center (PDC). For location of relay, refer to label
on underside of PDC cover.
(3) Start and run engine until it stalls.
(4) Attempt restarting engine until it will no
longer run.
(5) Turn ignition key to OFF position.
CAUTION: Steps 1, 2, 3 and 4 must be performed to
relieve high pressure fuel from within fuel rail. Do
not attempt to use following steps to relieve this
pressure as excessive fuel will be forced into a cyl-
inder chamber.
(6) Unplug connector from any fuel injector.
(7) Attach one end of a jumper wire with alligator
clips (18 gauge or smaller) to either injector terminal.(8) Connect other end of jumper wire to positive
side of battery.
(9) Connect one end of a second jumper wire to
remaining injector terminal.
CAUTION: Powering an injector for more than a few
seconds will permanently damage the injector.
(10) Momentarily touch other end of jumper wire
to negative terminal of battery for no more than a
few seconds.
(11) Place a rag or towel below fuel line quick-con-
nect fitting at fuel rail.
(12) Disconnect quick-connect fitting at fuel rail.
Refer to Quick-Connect Fittings.
(13) Return fuel pump relay to PDC.
(14) One or more Diagnostic Trouble Codes (DTC's)
may have been stored in PCM memory due to fuel
pump relay removal. The DRBtscan tool must be
used to erase a DTC.
SPECIFICATIONS
FUEL SYSTEM PRESSURE
339 kPa   34 kPa (49.2 psi   5 psi).
TORQUE - FUEL DELIVERY
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Accelerator Pedal Bracket Mounting Nuts
(without adjustable pedals)12  2 - 105  20
Fuel Filter/Fuel Press. Reg. Bolts 3 - 26
Fuel Hose Clamps 3 - 26
Fuel Injector Rail Mounting Bolts -4.0L Engine 11 - 100
Fuel Injector Rail Mounting Bolts -4.7L V-8
Engine11 - 100
Fuel Pump Module Locknut 74 55 -
Fuel Tank Filler Tube-to-Body Mounting Bolts 2 - 15
Fuel Tank-to-Body Mounting Bolts 88 65 -
Fuel Tank Support Bracket Bolts (large brackets) 88 65 -
Fuel Tank Support Bracket Bolts (small bracket) 5 - 45
Fuel Tank Support Bracket Nuts (large brackets) 61 45 -
Fuel Tank Heat Shield Nuts (shield-to-tank) 9 - 85
Fuel Tank Heat Shield Nuts (shield-to-body) 3 - 25
14 - 4 FUEL DELIVERYWJ
FUEL DELIVERY (Continued)

Both the manual A/C Heater control panel and the
AZC control panel are serviced only as complete
units and cannot be repaired. If faulty or damaged,
the entire control panel unit must be replaced.
DIAGNOSIS AND TESTING - AUTOMATIC ZONE
CONTROL SYSTEM
The Automatic Zone Control (AZC) control module
has a system self-diagnostic mode which continuously
monitors various parameters during normal system
operation. If a system fault is detected, a current and
historical fault is recorded. When the current fault is
cleared, the historical fault remains until reset (man-
ually or automatically). Both the current and histor-
ical fault codes can be accessed through either the
front panel, or over the Programmable Communica-
tions Interface (PCI) bus using a DRBIIItscan tool,
and the appropriate diagnostic information.
The AZC control module is capable of three differ-
ent types of self-diagnostic tests, as follows:
²Fault Code Tests
²Input Circuit Tests
²Output Circuit/Actuator Tests
The information that follows describes:
²How to read the self-diagnostic display
²How to enter the AZC control module self-diag-
nostic test mode
²How to select the self-diagnostic test types
²How to perform the different tests
ENTERING THE AZC SELF-DIAGNOSTIC MODE
To enter the AZC self-diagnostic mode, perform the
following:
(1) Depress the a/c and recirc buttons at the same
time and hold. Rotate the left temperature control
knob clockwise (CW) one detent.
(2) If you continue to keep the a/c and recirc but-
tons depressed, the AZC control module will perform
a Segment Test of the Vacuum Fluorescent (VF) dis-
play. In the Segment Test you should see all of the
display segments illuminate as long as both buttons
are held. If a display segment fails to illuminate, the
vacuum fluorescent display is faulty and the a/c
heater control must be replaced.
(3) After viewing the Segment Test, release the
A/C and Recirc buttons and the display will clear
momentarily.Ifa0isdisplayed, then no faults
are set in the system.Should there be any faults,
either9current9or9historical9, all fault codes will be
displayed in ascending numerical sequence (note no
effort is made to display fault codes in chronological
order). Each fault code is displayed for one second
before the next code is displayed. Once all fault codes
have been displayed, the system will then repeat the
fault code numbers. This will continue until the left
side set temperature control is moved at least onedetent position in the CW direction or the ignition is
turned9OFF9.
FAULT CODE TESTS
Fault codes are two-digit numbers that identify a
circuit that is malfunctioning. There are two differ-
ent kinds of fault codes.
1.Current Fault Codes- Current means the
fault is present right now. There are two types of cur-
rent faults: input faults, and system faults.
2.Historical Fault Codes- Historical or stored
means that the fault occurred previously, but is not
present right now. A majority of historical fault codes
are caused by intermittent wire harness or wire har-
ness connector problems.
CURRENT FAULT CODES
Input faults 01 = IR thermister circuit
open
02 = IR thermister circuit
shorted
03 = Fan pot shorted
04 = Fan pot open
05 = Mode pot shorted
06 = Mode pot open
07 = IR sensor delta too
large
08 = Reserved
09 = Reserved
10 = One of four motor
drivers has drive9A9
shorted to ground
11 = Engine air intake
temperature Buss
message missing
12 = Country code Buss
message missing
24 - 18 CONTROLSWJ
A/C HEATER CONTROL (Continued)