2003 JEEP GRAND CHEROKEE Fill

CAUTION: When installing the serpentine engine
accessory drive belt, the belt MUST be routed cor-
rectly. If not, the engine may overheat due to the
water pump rotating in the wrong direction. Refer to
the Belt Removal and Installtion in this group for
appropriate belt routing. You may also refer to the
Belt Routing Label in the vehicle engine compart-
ment.
Install accessory drive belt (Refer to 7 - COOLING/
ACCESSORY DRIVE/DRIVE BELTS - INSTALLA-
TION).
(6) Install fan blade and viscous fan drive onto
water pump.
(7) Fill cooling system with coolant and check for
leaks. (Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(8) Connect battery cable to battery.
(9) Start and warm the engine. Check for leaks.
RADIATOR PRESSURE CAP
DESCRIPTION
All radiators are equipped with a pressure cap
(Fig. 50). This cap releases pressure at some point
within a range of 124-to-145 kPa (18-to-21 psi). The
pressure relief point (in pounds) is engraved on top of
the cap
The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi-
ator cooling capacity. The cap contains a spring-
loaded pressure relief valve. This valve opens when
system pressure reaches the release range of 124-to-
145 kPa (18-to-21 psi).
A rubber gasket seals the radiator filler neck. This is
done to maintain vacuum during coolant cool-down and
to prevent leakage when system is under pressure.
OPERATION
A vent valve in the center of the cap will remain
shut as long as the cooling system is pressurized. As
the coolant cools, it contracts and creates a vacuum
in cooling system. This causes the vacuum valve to
open and coolant in reserve/overflow tank to be
drawn through connecting hose into radiator. If the
vacuum valve is stuck shut, or overflow hose is
kinked, radiator hoses will collapse on cool-down.
DIAGNOSIS AND TESTINGÐRADIATOR
PRESSURE CAP
Remove cap from radiator. Be sure that sealing
surfaces are clean. Moisten rubber gasket with water
and install the cap on pressure tester (tool 7700 or
an equivalent) (Fig. 51).Operate the tester pump and observe the gauge
pointer at its highest point. The cap release pressure
should be 124 to 145 kPa (18 to 21 psi). The cap is
satisfactory when the pressure holds steady. It is also
good if it holds pressure within the 124 to 145 kPa
(18 to 21 psi) range for 30 seconds or more. If the
pointer drops quickly, replace the cap.
CAUTION: Radiator pressure testing tools are very
sensitive to small air leaks, which will not cause
cooling system problems. A pressure cap that does
not have a history of coolant loss should not be
replaced just because it leaks slowly when tested
with this tool. Add water to tool. Turn tool upside
down and recheck pressure cap to confirm that cap
needs replacement.CLEANING
Clean the radiator pressure cap using a mild soap
and water only.
Fig. 50 Radiator Pressure Cap - Typical
1 - FILLER NECK SEAL
2 - VACUUM VENT VALVE
3 - PRESSURE RATING
4 - PRESSURE VALVE
WJENGINE 7 - 53
WATER PUMP - 4.0L (Continued)

INSPECTION
Visually inspect the pressure valve gasket on the
cap. Replace cap if the gasket is swollen, torn or
worn. Inspect the area around radiator filler neck for
white deposits that indicate a leaking cap.
WATER PUMP INLET TUBE
REMOVAL
WARNING: CONSTANT TENSION HOSE CLAMPS
ARE USED ON MOST COOLING SYSTEM HOSES.
WHEN REMOVING OR INSTALLING, USE ONLY
TOOLS DESIGNED FOR SERVICING THIS TYPE OF
CLAMP, SUCH AS SPECIAL CLAMP TOOL (NUMBER
6094) (Fig. 52). SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS.
ALWAYS WEAR SAFETY GLASSES WHEN SERVIC-
ING CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps (Fig. 53). If
replacement is necessary, use only an original
equipment clamp with matching number or letter.
(1) Partially drain cooling system .
(2) Do not waste reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.(3) Loosen both bypass hose clamps (Fig. 52) and
position to center of hose. Remove hose from vehicle.
INSTALLATION
(1) Position bypass hose clamps (Fig. 52) to center
of hose.
(2) Install bypass hose to engine.
(3) Secure both hose clamps (Fig. 52).
(4) Refill cooling system .
(5) Start and warm the engine. Check for leaks.
Fig. 51 Pressure Testing Radiator Pressure
CapÐTypical
1 - PRESSURE CAP
2 - TYPICAL COOLING SYSTEM PRESSURE TESTER
Fig. 52 Hose Clamp ToolÐTypical
1 - HOSE CLAMP TOOL 6094
2 - HOSE CLAMP
Fig. 53 Clamp Number/Letter Location
1 - TYPICAL CONSTANT TENSION HOSE CLAMP
2 - CLAMP NUMBER/LETTER LOCATION
3 - TYPICAL HOSE
7 - 54 ENGINEWJ
RADIATOR PRESSURE CAP (Continued)

TRANSMISSION
TABLE OF CONTENTS
page page
TRANS COOLER
DESCRIPTION.........................55STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES.................55
TRANS COOLER
DESCRIPTION
An internal high capacity/high efficiency cooler is
used on all vehicles these coolers are an oil-to-coolant
type which consists of plates mounted in the radiator
outlet tank (Fig. 36). Because the internal oil cooler
is so efficient, no auxiliary oil cooler is offered The
cooler is not servicable seperatly from the radiator.
STANDARD PROCEDURE - FLUSHING
COOLERS AND TUBES
When a transmission failure has contaminated the
fluid, the oil cooler(s) must be flushed. The torque
converter must also be replaced. This will insure that
metal particles or sludged oil are not later trans-
ferred back into the reconditioned (or replaced) trans-
mission.
The only recommended procedure for flushing cool-
ers and lines is to use Tool 6906-B Cooler Flusher.
WARNING: WEAR PROTECTIVE EYEWEAR THAT
MEETS THE REQUIREMENTS OF OSHA AND ANSI
Z87.1±1968. WEAR STANDARD INDUSTRIAL RUB-
BER GLOVES.
KEEP LIGHTED CIGARETTES, SPARKS, FLAMES,
AND OTHER IGNITION SOURCES AWAY FROM THE
AREA TO PREVENT THE IGNITION OF COMBUSTI-
BLE LIQUIDS AND GASES. KEEP A CLASS (B) FIRE
EXTINGUISHER IN THE AREA WHERE THE
FLUSHER WILL BE USED.
KEEP THE AREA WELL VENTILATED.
DO NOT LET FLUSHING SOLVENT COME IN CON-
TACT WITH YOUR EYES OR SKIN: IF EYE CONTAM-
INATION OCCURS, FLUSH EYES WITH WATER FOR
15 TO 20 SECONDS. REMOVE CONTAMINATED
CLOTHING AND WASH AFFECTED SKIN WITH
SOAP AND WATER. SEEK MEDICAL ATTENTION.
(1) Remove cover plate filler plug on Tool 6906-B.
Fill reservoir 1/2 to 3/4 full of fresh flushing solution.
Flushing solvents are petroleum based solutions gen-
erally used to clean automatic transmission compo-
nents.DO NOTuse solvents containing acids, water,
gasoline, or any other corrosive liquids.(2) Reinstall filler plug on Tool 6906-B.
(3) Verify pump power switch is turned OFF. Con-
nect red alligator clip to positive (+) battery post.
Connect black (-) alligator clip to a good ground.
(4) Disconnect the cooler lines at the transmission.
NOTE: When flushing transmission cooler and
lines, ALWAYS reverse flush.
NOTE: The converter drainback valve must be
removed and an appropriate replacement hose
installed to bridge the space between the transmis-
sion cooler line and the cooler fitting. Failure to
remove the drainback valve will prevent reverse
flushing the system. A suitable replacement hose
can be found in the adapter kit supplied with the
flushing tool.
(5) Connect the BLUE pressure line to the OUT-
LET (From) cooler line.
(6) Connect the CLEAR return line to the INLET
(To) cooler line
(7) Turn pump ON for two to three minutes to
flush cooler(s) and lines.
(8) Turn pump OFF.
(9) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(10) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(11) Place CLEAR suction line into a one quart
container of MopartATF +4, type 9602, Automatic
Transmission Fluid.
(12) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(13) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
WJTRANSMISSION 7 - 55

Before testing, visually inspect the battery for any
damage (a cracked case or cover, loose posts, etc.)
that would cause the battery to be faulty. In order to
obtain correct indications from the built-in indicator,
it is important that the battery be level and have a
clean sight glass. Additional light may be required to
view the indicator.Do not use open flame as a
source of additional light.
To read the built-in indicator, look into the sight
glass and note the color of the indication (Fig. 8). The
battery condition that each color indicates is
described in the following list:
²Green- Indicates 75% to 100% battery state-of-
charge. The battery is adequately charged for further
testing or return to service. If the starter will not
crank for a minimum of fifteen seconds with a fully-
charged battery, the battery must be load tested.
Refer to Standard Procedures for the proper battery
load test procedures.
²Black or Dark- Indicates 0% to 75% battery
state-of-charge. The battery is inadequately charged
and must be charged until a green indication is visi-
ble in the sight glass (12.4 volts or more), before the
battery is tested further or returned to service. Refer
to Standard Procedures for the proper battery charg-
ing procedures. Also refer to Diagnosis and Testing
for more information on the possible causes of the
discharged battery condition.
²Clear or Bright- Indicates a low battery elec-
trolyte level. The electrolyte level in the battery is
below the built-in indicator. A maintenance-free bat-
tery with non-removable cell caps must be replaced if
the electrolyte level is low. Water must be added to a
low-maintenance battery with removable cell caps
before it is charged. Refer to Standard Procedures for
the proper battery filling procedures. A low electro-
lyte level may be caused by an overcharging condi-
tion. Refer to Charging System for the proper
charging system diagnosis and testing procedures.STANDARD PROCEDURE - OPEN-CIRCUIT
VOLTAGE TEST
A battery open-circuit voltage (no load) test will
show the approximate state-of-charge of a battery.
This test can be used in place of the hydrometer test
when a hydrometer is not available, or for mainte-
nance-free batteries with non-removable cell caps.
Before proceeding with this test, completely charge
the battery (Refer to 8 - ELECTRICAL/BATTERY
SYSTEM/BATTERY - STANDARD PROCEDURE).
(1) Before measuring the open-circuit voltage, the
surface charge must be removed from the battery.
Turn on the headlamps for fifteen seconds, then
allow up to five minutes for the battery voltage to
stabilize.
(2) Disconnect and isolate both battery cables, neg-
ative cable first.
(3) Using a voltmeter connected to the battery
posts (see the instructions provided by the manufac-
turer of the voltmeter), measure the open-circuit volt-
age (Fig. 9).
See the Open-Circuit Voltage Table. This voltage
reading will indicate the battery state-of-charge, but
will not reveal its cranking capacity. If a battery has
an open-circuit voltage reading of 12.4 volts or
greater, it may be load tested to reveal its cranking
capacity (Refer to 8 - ELECTRICAL/BATTERY SYS-
TEM/BATTERY - STANDARD PROCEDURE).
OPEN CIRCUIT VOLTAGE TABLE
Open Circuit Voltage Charge Percentage
11.7 volts or less 0%
12.0 volts 25%
12.2 volts 50%
12.4 volts 75%
12.6 volts or more 100%
Fig. 8 Built-In Indicator Sight Glass Chart
Fig. 9 Testing Open-Circuit Voltage - Typical
8F - 12 BATTERY SYSTEMWJ
BATTERY (Continued)

OPERATION
Although cylinder firing order is the same as 4.0L
Jeep engines of previous years, spark plug firing is
not. The 3 coils dual-fire the spark plugs on cylinders
1-6, 2-5 and/or 3-4. When one cylinder is being fired
(on compression stroke), the spark to the opposite
cylinder is being wasted (on exhaust stroke).
Battery voltage is supplied to the three ignition
coils from the ASD relay. The Powertrain Control
Module (PCM) opens and closes the ignition coil
ground circuit for ignition coil operation.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used. The cables are integral
within the coil rail.
REMOVAL
A one-piece coil rail assembly containing three
individual coils is used on the 4.0L engine (Fig. 13).
The coil rail must be replaced as one assembly. The
bottom of the coil is equipped with 6 individual rub-
ber boots (Fig. 13) to seal the 6 spark plugs to the
coil. Inside each rubber boot is a spring. The spring
is used for an electrical contact between the coil and
the top of the spark plug. These rubber boots and
springs are a permanent part of the coil and are not
serviced separately.
(1) Disconnect negative battery cable at battery.
(2) The coil is bolted directly to the cylinder head.
Remove 4 coil mounting bolts (Fig. 14).
(3) Carefully pry up coil assembly from spark
plugs. Do this by prying alternately at each end of
coil until rubber boots have disengaged from all
spark plugs. If boots will not release from spark
plugs, use a commercially available spark plug boot
removal tool. Twist and loosen a few boots from a few
spark plugs to help remove coil.
(4) After coil has cleared spark plugs, position coil
for access to primary electrical connector. Disconnect
connector from coil by pushing slide tab outwards to
right side of vehicle (Fig. 15). After slide tab has been
positioned outwards, push in on secondary release
lock (Fig. 15) on side of connector and pull connector
from coil.
(5) Remove coil from vehicle.
Fig. 13 Ignition Coil AssemblyÐ4.0L 6±Cylinder
Engine
1 - CYL. #6
2 - CYL. #5
3 - CYL. #4
4 - CYL. #3
5 - CYL. #2
6 - CYL. #1
7 - COILS (3)
8 - MOUNTING BOLTS (4)
9 - BOLT BASES (4)
10 - RUBBER BOOTS (6)
Fig. 14 Ignition Coil Rail LocationÐ4.0L 6±Cylinder
Engine
1 - COIL RAIL
2 - COIL MOUNTING BOLTS (4)
3 - COIL
4 - COIL ELECTRICAL CONNECTION
8I - 10 IGNITION CONTROLWJ
COIL RAIL (Continued)

OPERATION
Battery voltage is supplied to the 8 ignition coils
from the ASD relay. The Powertrain Control Module
(PCM) opens and closes each ignition coil ground cir-
cuit at a determined time for ignition coil operation.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used.
REMOVAL
An individual ignition coil is used for each spark
plug (Fig. 18). The coil fits into machined holes in the
cylinder head. A mounting stud/nut secures each coil
to the top of the intake manifold (Fig. 19). The bot-
tom of the coil is equipped with a rubber boot to seal
the spark plug to the coil. Inside each rubber boot is
a spring. The spring is used for a mechanical contact
between the coil and the top of the spark plug. These
rubber boots and springs are a permanent part of the
coil and are not serviced separately. An o-ring (Fig.
18) is used to seal the coil at the opening into the cyl-
inder head.
(1) Depending on which coil is being removed, the
throttle body air intake tube or intake box may need
to be removed to gain access to coil.
(2) Disconnect electrical connector (Fig. 19) from
coil by pushing downward on release lock on top of
connector and pull connector from coil.
(3) Clean area at base of coil with compressed air
before removal.
(4) Remove coil mounting nut from mounting stud
(Fig. 19).
(5) Carefully pull up coil from cylinder head open-
ing with a slight twisting action.
(6) Remove coil from vehicle.
INSTALLATION
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Check condition of coil o-ring and replace as
necessary. To aid in coil installation, apply silicone to
coil o-ring.
(3) Position ignition coil into cylinder head opening
and push onto spark plug. Do this while guiding coil
base over mounting stud.
(4) Install mounting stud nut and tighten to 8 N´m
(70 in. lbs.) torque.(5) Connect electrical connector to coil by snapping
into position.
(6) If necessary, install throttle body air tube or
box.
Fig. 18 Ignition CoilÐ4.7L V±8
1 - O-RING
2 - IGNITION COIL
3 - ELECTRICAL CONNECTOR
Fig. 19 Ignition Coil
1 - IGNITION COIL
2 - COIL ELECTRICAL CONNECTOR
3 - COIL MOUNTING STUD/NUT
8I - 12 IGNITION CONTROLWJ
IGNITION COIL (Continued)

FUEL GAUGE
DESCRIPTION
A fuel gauge is standard equipment on all instru-
ment clusters. The fuel gauge is located in the lower
left corner of the instrument cluster, to the left of the
tachometer. The fuel gauge consists of a movable
gauge needle or pointer controlled by the instrument
cluster circuitry and a fixed 90 degree scale on the
gauge dial face that reads left-to-right from E (or
Empty) to F (or Full). An International Control and
Display Symbol icon for ªFuelº is located on the
gauge dial face. An arrowhead pointed to the left side
of the vehicle is imprinted next to the ªFuelº icon on
the fuel gauge dial face to provide the driver with a
reminder as to the location of the fuel filler access.
The fuel gauge graphics are either white, gray and
orange against a black gauge dial face (base cluster)
or black and gray against a taupe gauge dial face
(premium cluster), making them clearly visible
within the instrument cluster in daylight. When illu-
minated from behind by the panel lamps dimmer
controlled cluster illumination lighting with the exte-
rior lamps turned On, the base cluster white gauge
graphics appear blue-green and the orange graphics
still appear orange, while the premium cluster taupe
gauge dial face appears blue-green with the black
graphics silhouetted against the illuminated back-
ground. The gray gauge graphics for both versions of
the cluster are not illuminated. The orange gauge
needle in the base cluster gauge is internally illumi-
nated, while the black gauge needle in the premium
cluster gauge is not.
Base cluster gauge illumination is provided by
replaceable incandescent bulb and bulb holder units
located on the instrument cluster electronic circuit
board. Premium cluster gauge illumination is pro-
vided by an integral electro-luminescent lamp that is
serviced as a unit with the instrument cluster. The
fuel gauge is serviced as a unit with the instrument
cluster.
OPERATION
The fuel gauge gives an indication to the vehicle
operator of the level of fuel in the fuel tank. This
gauge is controlled by the instrument cluster circuit
board based upon cluster programming and elec-
tronic messages received by the cluster from the
Powertrain Control Module (PCM) over the Program-
mable Communications Interface (PCI) data bus. The
fuel gauge is an air core magnetic unit that receives
battery current on the instrument cluster electronic
circuit board through the fused ignition switch out-
put (run-start) circuit whenever the ignition switch is
in the On or Start positions. The cluster is pro-
grammed to move the gauge needle back to the lowend of the scale after the ignition switch is turned to
the Off position. The instrument cluster circuitry
controls the gauge needle position and provides the
following features:
²Percent Tank Full Message- Each time the
cluster receives a message from the PCM indicating
the percent tank full, the cluster moves the gauge
needle to the relative fuel level position on the gauge
scale. The PCM applies an algorithm to the input
from the fuel tank sender to dampen gauge needle
movement against the negative effect that fuel slosh-
ing within the fuel tank can have on accurate inputs
to the PCM.
²Less Than 12.5 Percent Tank Full Message-
Each time the cluster receives messages from the
PCM indicating the percent tank full is less than
12.5 (one-eighth), the gauge needle is moved to the
proper position on the gauge scale and the low fuel
indicator is illuminated. The low fuel indicator
remains illuminated until the cluster receives mes-
sages from the PCM indicating that the percent tank
full is greater than 12.5 (one-eighth), or until the
ignition switch is turned to the Off position, which-
ever occurs first.
²Less Than Empty Percent Tank Full Mes-
sage- Each time the cluster receives a message from
the PCM indicating the percent tank full is less than
empty, the gauge needle is moved to the far left (low)
end of the gauge scale and the low fuel indicator is
illuminated immediately. This message would indi-
cate that the fuel tank sender input to the PCM is a
short circuit.
²More Than Full Percent Tank Full Message
- Each time the cluster receives a message from the
PCM indicating the percent tank full is more than
full, the gauge needle is moved to the far left (low)
end of the gauge scale and the low fuel indicator is
illuminated immediately. This message would indi-
cate that the fuel tank sender input to the PCM is an
open circuit.
²Communication Error- If the cluster fails to
receive a percent tank full message, it will hold the
gauge needle at the last indication for about twelve
seconds, until a new message is received, or until the
ignition switch is turned to the Off position, which-
ever occurs first. After twelve seconds, the cluster
will return the gauge needle to the low end of the
gauge scale.
²Actuator Test- Each time the cluster is put
through the actuator test, the gauge needle will be
swept across the entire gauge scale and back in order
to confirm the functionality of the gauge and the
cluster control circuitry.
The PCM continually monitors the fuel tank
sender to determine the fuel level. The PCM then
applies an algorithm to the input and sends the
WJINSTRUMENT CLUSTER 8J - 21

WARNING: USE EXTREME CARE TO PREVENT ANY
FOREIGN MATERIAL FROM ENTERING THE DRIVER
AIRBAG, OR BECOMING ENTRAPPED BETWEEN
THE DRIVER AIRBAG CUSHION AND THE DRIVER
AIRBAG TRIM COVER. FAILURE TO OBSERVE THIS
WARNING COULD RESULT IN OCCUPANT INJURIES
UPON AIRBAG DEPLOYMENT.
WARNING: THE DRIVER AIRBAG TRIM COVER
MUST NEVER BE PAINTED. REPLACEMENT AIR-
BAGS AND TRIM COVERS ARE SERVICED IN THE
ORIGINAL COLORS. PAINT MAY CHANGE THE WAY
IN WHICH THE MATERIAL OF THE TRIM COVER
RESPONDS TO AN AIRBAG DEPLOYMENT. FAIL-
URE TO OBSERVE THIS WARNING COULD RESULT
IN OCCUPANT INJURIES UPON AIRBAG DEPLOY-
MENT.
(1) Assemble the driver airbag trim cover onto the
airbag housing. (Refer to 8 - ELECTRICAL/RE-
STRAINTS/DRIVER AIRBAG - ASSEMBLY).
(2) Position the driver airbag close enough to the
steering wheel to reconnect all three electrical con-
nections on the back of the airbag housing.
(3) When installing the driver airbag, reconnect
the two clockspring driver airbag pigtail wire connec-
tors to the airbag inflator connector receptacles by
pressing straight in on the connectors (Fig. 19), then
pushing the locks straight into the connectors. You
can be certain that the connector is fully engaged by
listening carefully for a distinct, audible click as the
connector latches snap into place.
(4) Reconnect the steering wheel wire harness con-
nector for the horn switch to the horn switch feed
pigtail wire connector, which is located at the back of
the driver airbag housing.
(5) Carefully position the driver airbag in the
steering wheel. Be certain that the clockspring pig-
tail wires and steering wheel wire harness in the
steering wheel hub area are not pinched between the
driver airbag and the steering wheel armature.
(6) From the underside of the steering wheel,
install and tighten the two screws that secure the
driver airbag to the steering wheel armature.
Tighten the screws to 10 N´m (90 in. lbs.).
(7) Do not reconnect the battery negative cable at
this time. The supplemental restraint system verifi-
cation test procedure should be performed following
service of any supplemental restraint system compo-
nent. (Refer to 8 - ELECTRICAL/RESTRAINTS -
STANDARD PROCEDURE - VERIFICATION TEST).FRONT IMPACT SENSOR
DESCRIPTION
Two front impact sensors are used on this model,
one each for the left and right sides of the vehicle
(Fig. 24). These sensors are mounted remotely from
the impact sensor that is internal to the Airbag Con-
trol Module (ACM). The right and left front and side
impact sensors are identical in construction and cal-
ibration with the exception of the right-hand and
left-hand die cast aluminum mounting brackets to
which each front impact sensor is secured with two
screws. The front impact sensor brackets are secured
with three screws to the front and inboard sides of
the right and left vertical members of the radiator
support within the engine compartment.
The impact sensor housing has an integral connec-
tor receptacle and two integral mounting ears, each
with a metal sleeve to provide crush protection. A cav-
ity in the center of the molded black plastic impact
sensor housing contains the electronic circuitry of the
sensor which includes an electronic communication
chip and an electronic impact sensor. Potting material
fills the cavity to seal and protect the internal elec-
tronic circuitry and components. The front impact sen-
sors are each connected to the vehicle electrical
system through a dedicated take out and connector of
the right or left headlamp and dash wire harnesses.
The front impact sensors cannot be repaired or
adjusted and, if damaged or faulty, they must be
replaced. If a front impact sensor is faulty, only the
sensor needs to be replaced. If the sensor or the sen-
sor mounting bracket is damaged or faulty, or if
proper tightening torque of the screws that secure
the sensor to the bracket cannot be achieved, the
sensor and bracket unit must be replaced.
Fig. 24 Front Impact Sensor
1 - SENSOR
2 - CONNECTOR RECEPTACLE
WJRESTRAINTS 8O - 23
DRIVER AIRBAG (Continued)