1995 JEEP YJ battery

EXAMPLES:
²If the lamp (Figs. 5 or 6) flashes 1 time, pauses
and flashes 2 more times, a flashing Diagnostic Trou-
ble Code (DTC) number 12 is indicated. If this code is
observed, it is indicating that the battery has been
disconnected within the last 50 key-on cycles. It
could also indicate that battery voltage has been dis-
connected to the PCM. In either case, other DTC's
may have been erased.
²If the lamp flashes 1 time, pauses and flashes 7
more times, a flashing Diagnostic Trouble Code
(DTC) number 17 is indicated.
²If the lamp flashes 3 times, pauses and flashes 5
more times, a flashing Diagnostic Trouble Code
(DTC) number 35 is indicated.
After any stored DTC information has been ob-
served, the display will end with a flashing DTC
number 55. This will indicate the end of all stored in-
formation.
ERASING TROUBLE CODES
After the problem has been repaired, the DRB scan
tool must be used to erase a DTC. Refer to the ap-
propriate Powertrain Diagnostic Procedures service
manual for operation of the DRB scan tool.
DRB SCAN TOOL
For operation of the DRB scan tool, refer to the ap-
propriate Powertrain Diagnostic Procedures service
manual.
PRELIMINARY 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.
1. PROLONGED IDLE, VERY HIGH AMBIENT
TEMPERATURE, SLIGHT TAIL WIND AT IDLE,
SLOW TRAFFIC, TRAFFIC JAMS, HIGH
SPEED, OR STEEP GRADES:
Driving techniques that avoid overheating are:
²Idle with A/C off when temperature gauge is at
end of normal range.
²Increasing engine speed for more air flow is recom-
mended.
2. TRAILER TOWING:
Consult Trailer Towing section of owners manual.
Do not exceed limits.
3. AIR CONDITIONING; ADD-ON OR AFTER
MARKET:
A maximum cooling package should have been or-
dered with vehicle if add-on or after market A/C is
installed. If not, maximum cooling system compo-
nents should be installed for model involved per
manufacturer's specifications.
4. RECENT SERVICE OR ACCIDENT REPAIR:
Determine if any recent service has been performed
on vehicle that may effect cooling system. This may
be:
²Engine adjustments (incorrect timing)
²Slipping engine accessory drive belt(s)
²Brakes (possibly dragging)
²Changed parts (incorrect water pump rotating in
wrong direction)
²Reconditioned radiator or cooling system refilling
(possibly under-filled or air trapped in system).
If investigation reveals none of the previous
items as a cause for an engine overheating com-
plaint, refer to following Cooling System Diag-
nosis charts.
These charts are to be used as a quick-reference
only. Refer to the group text for information.
Fig. 7 Data Link ConnectorÐXJ ModelsÐTypical
Fig. 8 Data Link ConnectorÐYJ ModelsÐTypical
JCOOLING SYSTEM DIAGNOSIS 7 - 5

INSPECTING FOR INLET RESTRICTIONS
Inadequate heater performance may be caused by a
metal casting restriction in the water pump heater
hose inlet.
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND UNDER
PRESSURE. SERIOUS BURNS FROM THE COOL-
ANT CAN OCCUR.
(1) Drain sufficient coolant from the radiator to de-
crease the level below the water pump heater hose
inlet.
(2) Remove the heater hose.
(3) Inspect the inlet for metal casting flash or
other restrictions.
Remove the pump from engine before remov-
ing restriction to prevent contamination of the
coolant with debris. Refer to Water Pump Re-
moval.
WATER PUMPSÐREMOVAL/INSTALLATION
REMOVALÐALL MODELS
CAUTION: If the water pump is replaced because of
mechanical damage, the fan blades and viscous fan
drive should also be inspected. These components
could have been damaged due to excessive vibra-
tion.The water pump on all models can be removed
without discharging the air conditioning system (if
equipped).
CAUTION: All engines have a reverse (counter-
clockwise) rotating water pump. The letter R is
stamped into the back of the water pump impeller
(Fig. 1) to identify. Engines from previous model
years, depending upon application, may be
equipped with a forward (clockwise) rotating water
pump. Installation of the wrong water pump will
cause engine over heating.
The water pump impeller is pressed on the rear of
the pump shaft and bearing assembly. The water
pump is serviced only as a complete assembly.
WARNING: DO NOT REMOVE THE BLOCK DRAIN
PLUG(S) OR LOOSEN RADIATOR DRAINCOCK
WITH THE SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
DO NOT WASTE reusable coolant. If the solution
is clean, drain coolant into a clean container for re-
use.
(1) Disconnect negative battery cable at battery.
(2) Drain the cooling system. Refer to Draining
Cooling System in this group.
(3)XJ models with 4.0L 6-cylinder engine
equipped with A/C or heavy duty cooling sys-
tem:
Loosen (but do not remove at this time) the four
water pump pulley-to-water pump hub mounting
bolts (Fig. 3).
XJ models with 4.0L 6-cylinder engine with-
out A/C or heavy duty cooling system; or any
2.5L 4-cylinder engines; or any YJ models:
Loosen (but do not remove at this time) the four
fan hub-to-water pump pulley mounting nuts (Fig. 4).
Fig. 2 Impeller TestÐTypical
Fig. 3 Water Pump Pulley Bolts
7 - 14 COOLING SYSTEM SERVICE PROCEDURESJ

INSTALLATIONÐALL MODELS
(1) If pump is being replaced, install the heater
hose fitting to the pump. Use a sealant on the fitting
such as MoparŸ Thread Sealant With Teflon. Refer
to the directions on the package.
(2) Clean the gasket mating surfaces. If the origi-
nal pump is used, remove any deposits or other for-
eign material. Inspect the cylinder block and water
pump mating surfaces for erosion or damage from
cavitation.
(3) Install the gasket and water pump. The silicone
bead on the gasket should be facing the water pump.
Also, the gasket is installed dry. Tighten mounting
bolts to 30 Nzm (22 ft. lbs.) torque. Rotate the shaft
by hand to be sure it turns freely.
(4) Connect the radiator and heater hoses to the
water pump.
(5) Position water pump pulley to water pump hub.
(6) If equipped with a water pump mounted fan,
install fan and four nuts to water pump hub. If not
equipped with a water pump mounted fan, install
four pump hub bolts. Tighten bolts (or nuts) to 27
Nzm (20 ft. lbs.) torque.
(7) Position power steering pump bracket to en-
gine. Install bolts E, F and G (Fig. 7). Tighten bolts F
andGto38Nzm (28 ft. lbs.) torque. Tighten bolt E to
27 Nzm (20 ft. lbs.) torque.
(8) Position power steering pump to mounting
bracket. Install pivot bolt B (Fig. 6) finger tight. In-
stall locknut C and adjustment bolt D (Figs. 6 or 7)
finger tight.
(9) Install two adjustment bolts A (Fig. 6) finger
tight.
(10) Install idler pulley.
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
figures 11, 12, 13 or 14 for appropriate belt routing.
You may also refer to the Belt Routing Label in the ve-
hicle engine compartment.
(11) Position drive belt to pulleys.
(12) Tighten belt adjustment bolt D (Fig. 5) to the
proper tension. Refer to the Specifications section at
the end of this group for belt tension.
(13) Tighten bolts A (Fig. 5) to 27 Nzm (20 ft. lbs.)
torque.
(14) Tighten pivot bolt B (Fig. 6) to 27 Nzm (20 ft.
lbs.) torque.
(15) Tighten locknut C (Fig. 6) to 27 Nzm (20 ft.
lbs.) torque.
(16) After the power steering pump has been tight-
ened, recheck belt tension.
(17) Fill cooling system with coolant and check for
leaks. Refer to Refilling Cooling System in this
group.(18) Connect battery cable to battery.
(19) Start and warm the engine. Check for leaks.
THERMOSTAT
DESCRIPTION AND OPERATION
A pellet-type thermostat controls the operating
temperature of the engine by controlling the amount
of coolant flow to the radiator. On all engines the
thermostat is closed below 195ÉF (90ÉC). Above this
Fig. 11 YJ Models with 4.0L Engine, and XJ Models
with 2.5L 4-Cylinder EngineÐWith A/C
Fig. 12 YJ Models With 2.5L or 4.0L Engine, and XJ
Models with 2.5L EngineÐWithout A/C
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 17

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. 27). SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS. AL-
WAYS WEAR SAFETY GLASSES WHEN SERVICING
CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps (Fig. 28). If re-
placement is necessary, use only an original equip-
ment clamp with matching number or letter.XJ MODELS WITH 2.5L 4-CYLINDER ENGINE
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Observe the previousWARNINGS.Remove ra-
diator cap.
(3) Position drain pan under draincock. Open radi-
ator draincock. Drain radiator.
(4) Remove radiator upper and lower hose clamps
(Figs. 27 and 28). Remove hoses.
(5) Remove E-clip from alignment dowel at radia-
tor lower mounting bracket (Fig. 29).
(6) Disconnect coolant reserve/overflow tank hose
from radiator.
(7) Remove four radiator fan shroud mounting
bolts (Fig. 29). Push shroud back against front of en-
gine.
(8) If equipped, disconnect and plug automatic
transmission fluid cooler lines. Refer to Group 21,
Transmission for procedures.
(9) Remove two radiator top mounting bolts (Fig.
29).
(10) (a) If equipped with air conditioning, remove
the radiator grille mounting screws and remove grill.
Refer to Group 23, Body for procedures.
(b) If equipped, remove the air conditioning con-
denser-to-radiator mounting bolt. Use an open end
wrench to remove bottom bolts (Fig. 30).
(11) Lift radiator straight up and out of vehicle.
Take care not to damage radiator fins. When remov-
ing radiator, note position of the rubber seals located
on the top, bottom and sides of radiator (Fig. 29). To
prevent possible overheating, these seals must be in-
stalled to their original positions.
INSTALLATION
(1) Install radiator behind air conditioning con-
denser with bottom alignment dowel inserted into ra-
diator lower mounting bracket (Fig. 29).
(2) Install E-clip to radiator alignment dowel (Fig.
29).
(3) Tighten the four condenser-to-radiator mount-
ing bolts to 6.2 Nzm (55 in. lbs.) torque.
(4) If removed, install radiator grille.
(5) Tighten radiator top mounting bolts to 6 Nzm
(55 in. lbs.) torque.
(6) If equipped, connect automatic transmission
fluid cooler lines to radiator. Refer to Group 21,
Transmission for procedures.
(7) Install the radiator fan shroud.
(8) Connect the coolant reserve/overflow tank hose.
(9) Connect radiator hoses and install hose clamps.
(10) Connect negative battery cable.
(11) Close the draincock.
(12) Fill cooling system with correct coolant.
(13) Install radiator cap.
(14) Check and adjust automatic transmission
fluid level (if equipped).
Fig. 27 Hose Clamp ToolÐTypical
Fig. 28 Clamp Number/Letter Location
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 27

XJ MODELS WITH 4.0L 6-CYLINDER ENGINE
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATORDRAINCOCK WITH THE SYSTEM HOT AND PRES-
SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
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. 27). SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS. AL-
WAYS WEAR SAFETY GLASSES WHEN SERVICING
CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps (Fig. 28). If re-
placement is necessary, use only an original equip-
ment clamp with matching number or letter.
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Observe the previousWARNINGS.
(3) Remove pressure cap.
Fig. 29 Radiator Remove/InstallÐXJ ModelsÐ2.5L 4-Cylinder Engine
Fig. 30 Condenser Mounting BoltsÐXJ ModelsÐ
2.5L 4-Cylinder EngineÐTypical
7 - 28 COOLING SYSTEM SERVICE PROCEDURESJ

(13) Remove four radiator upper crossmember
bolts (Fig. 32) and remove upper crossmember.
(14) If equipped with air conditioning, separate ra-
diator from condenser by removing condenser-to-radi-
ator mounting brackets (Fig. 33).
(15) Lift radiator straight up and out of engine
compartment taking care not to damage fins.
INSTALLATION
The radiator is supplied with two alignment dowels
(Figs. 32 or 34). They are located on the bottom tank
and fit into rubber grommets in the radiator lower
crossmember.
(1) Lower radiator into engine compartment. Posi-
tion alignment dowels into rubber grommets in radi-
ator lower crossmember (Figs. 32 or 34).
(2) If equipped with air conditioning, attach con-
denser to radiator with mounting brackets (Fig. 33).
(3) Install radiator upper crossmember and four
mounting bolts.
(4) Install radiator upper crossmember-to-isolator
nuts. Tighten nuts to 10 Nzm (86 in. lbs.) torque. If
isolator-to-radiator nuts had been removed, tighten
them to 5 Nzm (47 in. lbs.) torque.
(5) Install hood latch striker. Note previously
marked position.
(6) Connect radiator upper and lower hoses.
(7) If equipped, connect automatic transmission
fluid cooler lines. Refer to Group 21, Transmissions
for procedures. If equipped with remote cooler, attach
cooler line to bracket at bottom of radiator.
(8) Install electric cooling fan (if equipped). Insert
alignment tabs at bottom of fan shroud into slots inbracket at bottom of radiator. Tighten mounting bolts
to3Nzm (31 in. lbs.) torque.
(9) Connect electric cooling fan electrical connector.
(10) Install mechanical cooling fan shroud. Insert
alignment tabs at bottom of shroud into slots in
bracket at bottom of radiator. Tighten mounting bolts
to3Nzm (31 in. lbs.) torque.
(11) Close radiator draincock.
(12) Install grille.
(13) Connect negative battery cable.
(14) Fill cooling system with correct coolant. Refer
to the Coolant section of this group.
(15) Install pressure cap.
(16) Check and adjust automatic transmission
fluid level (if equipped).
YJ MODELS
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR
DRAINCOCK WITH THE SYSTEM HOT AND PRES-
SURIZED. SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
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. 27). SNAP-ON CLAMP TOOL (NUMBER
HPC-20) MAY BE USED FOR LARGER CLAMPS. AL-
Fig. 33 Condenser-to-Radiator Mounting BracketsÐ
XJ with 4.0L 6- Cylinder Engine
Fig. 34 Radiator InstallationÐXJ Models with 4.0L
6-Cylinder Engine
7 - 30 COOLING SYSTEM SERVICE PROCEDURESJ

WAYS WEAR SAFETY GLASSES WHEN SERVICING
CONSTANT TENSION CLAMPS.
CAUTION: A number or letter is stamped into the
tongue of constant tension clamps (Fig. 28). If re-
placement is necessary, use only an original equip-
ment clamp with matching number or letter.
REMOVAL
(1) Disconnect negative battery cable at battery.
(2) Observe the previousWARNINGS.Remove the
radiator cap.
(3) Position drain pan under draincock. Open radi-
ator draincock and drain radiator.
(4) Remove radiator upper and lower hose clamps
(Figs 27 and 28). Remove radiator hoses.
(5) Disconnect coolant reserve/overflow tank hose
from radiator.
(6) Remove the four fan shroud mounting bolts
(Fig. 35). On some models the power steering fluid
reservoir tank is attached to the side of the fan
shroud. Tie the reservoir back to prevent spillage. Po-
sition the fan shroud back over the fan blades.
(7) If equipped, disconnect and plug automatic
transmission fluid cooler lines.(8) Remove six radiator mounting bolts. Position
the front axle vent hose (Fig. 35) to the side.
(9) Lift radiator straight up and out of vehicle tak-
ing care not to damage radiator fins.
When removing radiator, note position of the rub-
ber seals located on the top and bottom of radiator
(figure 35 on certain models only). To prevent possi-
ble overheating, these seals must be installed to their
original positions.
INSTALLATION
(1) Position the radiator. Install and tighten the
six mounting bolts (Fig. 35) to 8 Nzm (72 in. lbs.)
torque.
(2) Close radiator draincock.
(3) Position fan shroud and power steering reser-
voir tank (if equipped). Install and tighten four
mounting bolts to 8 Nzm (72 in. lbs.) torque.
(4) If equipped, remove plugs and connect auto-
matic transmission fluid cooler lines.
(5) Connect radiator hoses and install hose clamps.
(6) Connect negative battery cable.
(7) Fill cooling system with correct coolant. Refer
to the Coolant section of this group.
(8) Connect reserve/overflow tank hose.
(9) Install radiator cap.
Fig. 35 RadiatorÐRemove/InstallÐYJ Models
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 31

(5) Be sure that the air conditioner (if equipped) is
turned off.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A DI-
RECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR FAN. DO
NOT WEAR LOOSE CLOTHING.
(6) Start the engine and operate at 2400 rpm.
Within ten minutes the air temperature (indicated on
the dial thermometer) should be up to 88É C (190É F).
Fan driveengagementshould have started to occur
at between 74É to 82É C (165É to 180É F). Engage-
ment is distinguishable by a definiteincreasein fan
flow noise (roaring). The timing light also will indi-
cate an increase in the speed of the fan.
(7) When the air temperature reaches 88É C (190É
F), remove the plastic sheet. Fan drivedisengage-
mentshould have started to occur at between 57É to
79É C (135É to 175É F). A definitedecreaseof fan
flow noise (roaring) should be noticed. If not, replace
the defective viscous fan drive unit.
VISCOUS FAN DRIVE REMOVAL/INSTALLATION
Refer to the previous section on Cooling System
Fan for removal and installation procedures of the
viscous drive unit.
Viscous Fan Drive Fluid Pump Out Require-
ment:After installing anewviscous fan drive, bring
the engine speed up to approximately 2000 rpm and
hold for approximately two minutes. This will ensure
proper fluid distribution within the drive.
AUXILIARY ELECTRIC COOLING FANÐXJ MODELS
WITH 4.0L 6-CYLINDER ENGINE
OPERATION
XJ models equipped with a 4.0L 6-cylinder engine
may also have an auxiliary electrical cooling fan.
This is with models that have air conditioning and/or
heavy duty cooling. The fan is controlled by the cool-
ing fan relay, which is located in the power distribu-
tion center (PDC). For the location of relay within
the PDC (Fig. 41), refer to the label on PDC cover.
When coolant temperature is above 88ÉC (190ÉF),
the powertrain control module (PCM) provides a
ground path for the fan relay. This ground is pro-
vided through pin/connector #31 of the PCM 60-way
connector. Battery voltage is then applied to the fan
through the relay. When coolant temperature is be-
low 88ÉC (190ÉF), the PCM opens the ground path to
the relay. This will prevent the cooling fan from be-
ing energized.
Whenever the air conditioning is operated, the
PCM engages the auxiliary cooling fan. It provides aground path to the cooling fan relay. This ground is
provided through pin/connector #31 of the PCM 60-
way connector.
DIAGNOSIS AND RELAY TESTING
The powertrain control module (PCM) will enter a
diagnostic trouble code (DTC) number 35 in memory
if it detects a problem in the auxiliary cooling fan re-
lay or circuit. This will be read as a flashing signal
at the instrument panel mounted Malfunction Indica-
tor Lamp (displayed on the instrument panel as the
CHECK ENGINE lampÐfigure 42). Refer to On-
Board Diagnostics in Group 14, Fuel Systems for in-
formation on accessing a DTC.
The DTC can also be accessed through the DRB
scan tool. Refer to the appropriate Powertrain Diag-
Fig. 41 PDCÐXJ Models
Fig. 42 Check Engine LampÐXJ ModelsÐTypical
JCOOLING SYSTEM SERVICE PROCEDURES 7 - 35