Oil pan removal JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual
[x] Cancel search | Manufacturer: JEEP, Model Year: 2002, Model line: GRAND CHEROKEE, Model: JEEP GRAND CHEROKEE 2002 WJ / 2.GPages: 2199, PDF Size: 76.01 MB
Page 85 of 2199

²New Bearings: 1.7 to 3.4 N´m (15 to 30 in. lbs.).
(9) Install propeller shaft with reference marks
aligned.
(10) Install brake rotors and calipers.
(11) Add gear lubricant if necessary.
(12) Install wheel and tire assemblies.
(13) Lower vehicle.
DIFFERENTIAL
REMOVAL
(1) Raise and support the vehicle.
(2) Remove lubricant fill hole plug from the differ-
ential housing cover.
(3) Remove differential cover and drain lubricant.
(4) Clean the housing cavity with a flushing oil,
light engine oil or lint free cloth.Never use water,
steam, kerosene or gasoline for cleaning.
(5) Remove hub bearings and axle shafts.
(6) Note installation reference letters stamped on
the bearing caps and housing machined sealing sur-
face (Fig. 38).
(7) Loosen the differential bearing cap bolts.
(8) Position Spreader W-129-B with Adapter Kit
6987B on differential locating holes (Fig. 39). Install
hold down clamps and tighten the tool turnbuckle
finger-tight.
Fig. 37 PINION COMPANION FLANGE
1 - COMPANION FLNAGE
2 - DIFFERENTIAL HOUSING
3 - SPANNER WRENCH
Fig. 38 BEARING CAP IDENTIFICATION
1 - REFERENCE LETTERS
2 - REFERENCE LETTERS
Fig. 39 DIFFERENTIAL SPREADER LOCATION
1 - DIFFERENTIAL HOUSING
2 - ADAPTER
3 - HOLD DOWN CLAMPS
4 - SPREADER
5 - TURNBUCKLE
3 - 40 FRONT AXLE - 186FBIWJ
COLLAPSIBLE SPACER (Continued)
Page 90 of 2199

PINION GEAR/RING GEAR
REMOVAL
NOTE: The ring gear and pinion are serviced as a
matched set. Nevar replace one gear without replac-
ing the other matching gear.
(1) Raise and support vehicle
(2) Mark pinion companion flange and propeller
shaft for installation alignment.
(3) Remove propeller shaft from pinion companion
flange and tie propeller shaft to underbody.
(4) Remove differential from axle housing.
(5) Place differential case in a vise with soft metal
jaw (Fig. 51).
(6) Remove bolts holding ring gear to differential
case.
NOTE: On Veri-LokTdifferential the side bearing
and oil feed plenum must be removed before
removing the ring gear bolts.
(7) Driver ring gear off the differential case with a
rawhide hammer (Fig. 51).(8) With Spanner Wrench 6958 and a short length
of 1 in. pipe, hold pinion companion flange and
remove pinion nut and washer (Fig. 52).
(9) Remove pinion companion flange from pinion
shaft with Remover C-452 and Flange Wrench
C-3281.
Fig. 50 DIFFERENTIAL CASE BEARING
1 - INSTALLER
2 - HANDLE
Fig. 51 RING GEAR
1 - DIFFERENTIAL CASE
2 - RING GEAR
3 - HAMMER
Fig. 52 Pinion Flange
1 - PINION FLANGE
2 - FRONT AXLE
3 - SPANNER WRENCH
WJFRONT AXLE - 186FBI 3 - 45
DIFFERENTIAL CASE BEARINGS (Continued)
Page 183 of 2199

ADJUSTABLE PEDAL SWITCH
REMOVAL
(1) Remove the steering column opening cover
(Fig. 2)(Refer to 23 - BODY/INSTRUMENT PANEL/
STEERING COLUMN OPENING COVER - REMOV-
AL).
(2) Disconnect the electrical connector from the
adjustable pedal switch.
(3) Remove the switch from the steering column
opening cover by squeezing the retaining clips
together and pushing the switch outwards (Fig. 3).
INSTALLATION
(1) Install the switch to the steering column open-
ing cover by pushing the switch inwards seating the
retaining clips to the steering column opening cover
(Fig. 3).
(2) Reconnect the electrical connector to the
adjustable pedal switch.
(3) Install the steering column opening cover (Fig.
2)(Refer to 23 - BODY/INSTRUMENT PANEL/
STEERING COLUMN OPENING COVER - INSTAL-
LATION).
BRAKE LINES
DESCRIPTION
Flexible rubber hose is used at both front brakes,
rear brakes and at the rear axle junction block. Dou-
ble walled steel tubing is used. Double inverted style
and ISO style flares are used on the brake lines.
DIAGNOSIS AND TESTING - BRAKE HOSES
AND LINES
Flexible rubber hose is used at both front and rear
brakes and at the rear axle junction block. Inspect
the hoses whenever the brake system is serviced, at
every engine oil change, or whenever the vehicle is in
for service.
Inspect the hoses for surface cracking, scuffing, or
worn spots. Replace any brake hose immediately if
the fabric casing of the hose is exposed due to cracks
or abrasions.
Also check brake hose installation. Faulty installa-
tion can result in kinked, twisted hoses, or contact
with the wheels and tires or other chassis compo-
nents. All of these conditions can lead to scuffing,
cracking and eventual failure.
The steel brake lines should be inspected periodi-
cally for evidence of corrosion, twists, kinks, leaks, or
other damage. Heavily corroded lines will eventually
rust through causing leaks. In any case, corroded or
damaged brake lines should be replaced.
Factory replacement brake lines and hoses are rec-
ommended to ensure quality, correct length and supe-
rior fatigue life. Care should be taken to make sure
that brake line and hose mating surfaces are clean
and free from nicks and burrs. Also remember that
right and left brake hoses are not interchangeable.
Use new copper gaskets at all caliper connections.
Be sure brake line connections are properly made
(not cross threaded) and tightened to recommended
torque.
Fig. 2 STEERING COLUMN OPENING COVER
REMOVAL/INSTALL
1 - INSTRUMENT PANEL TOP PAD
2 - STEERING COLUMN OPENING COVER
3 - SCREW (3)
Fig. 3 ADJUSTABLE PEDAL SWITCH
1 - RETAINING CLIPS
2 - ELECTRICAL CONNECTION
5 - 8 BRAKES - BASEWJ
Page 234 of 2199

Carefully remove radiator pressure cap from filler
neck and check coolant level. Push down on cap to
disengage it from stop tabs. Wipe inside of filler neck
and examine lower inside sealing seat for nicks,
cracks, paint, dirt and solder residue. Inspect radia-
tor-to- reserve/overflow tank hose for internal
obstructions. Insert a wire through the hose to be
sure it is not obstructed.
Inspect cams on outside of filler neck. If cams are
damaged, seating of pressure cap valve and tester
seal will be affected.
Attach pressure tester (7700 or an equivalent) to
radiator filler neck (Fig. 6).
Operate tester pump to apply 103.4 kPa (15 psi)
pressure to system. If hoses enlarge excessively or
bulges while testing, replace as necessary. Observe
gauge pointer and determine condition of cooling sys-
tem according to following criteria:
Holds Steady:If pointer remains steady for two
minutes, serious coolant leaks are not present in sys-
tem. However, there could be an internal leak that
does not appear with normal system test pressure. If
it is certain that coolant is being lost and leaks can-
not be detected, inspect for interior leakage or per-
form Internal Leakage Test.
Drops Slowly:Indicates a small leak or seepage
is occurring. Examine all connections for seepage or
slight leakage with a flashlight. Inspect radiator,
hoses, gasket edges and heater. Seal small leak holes
with a Sealer Lubricant (or equivalent). Repair leak
holes and inspect system again with pressure
applied.
Drops Quickly:Indicates that serious leakage is
occurring. Examine system for external leakage. If
leaks are not visible, inspect for internal leakage.
Large radiator leak holes should be repaired by a
reputable radiator repair shop.INTERNAL LEAKAGE INSPECTION
Remove engine oil pan drain plug and drain a
small amount of engine oil. If coolant is present in
the pan, it will drain first because it is heavier than
oil. An alternative method is to operate engine for a
short period to churn the oil. After this is done,
remove engine dipstick and inspect for water glob-
ules. Also inspect transmission dipstick for water
globules and transmission fluid cooler for leakage.
WARNING: WITH RADIATOR PRESSURE TESTER
TOOL INSTALLED ON RADIATOR, DO NOT ALLOW
PRESSURE TO EXCEED 110 KPA (20 PSI). PRES-
SURE WILL BUILD UP QUICKLY IF A COMBUSTION
LEAK IS PRESENT. TO RELEASE PRESSURE,
ROCK TESTER FROM SIDE TO SIDE. WHEN
REMOVING TESTER, DO NOT TURN TESTER MORE
THAN 1/2 TURN IF SYSTEM IS UNDER PRESSURE.
Operate engine without pressure cap on radiator
until thermostat opens. Attach a Pressure Tester to
filler neck. If pressure builds up quickly it indicates a
combustion leak exists. This is usually the result of a
cylinder head gasket leak or crack in engine. Repair
as necessary.
If there is not an immediate pressure increase,
pump the Pressure Tester. Do this until indicated
pressure is within system range of 110 kPa (16 psi).
Fluctuation of gauge pointer indicates compression or
combustion leakage into cooling system.
Because the vehicle is equipped with a catalytic
converter,do notremove spark plug cables or short
out cylinders to isolate compression leak.
If the needle on dial of pressure tester does not
fluctuate, race engine a few times to check for an
abnormal amount of coolant or steam. This would be
emitting from exhaust pipe. Coolant or steam from
exhaust pipe may indicate a faulty cylinder head gas-
ket, cracked engine cylinder block or cylinder head.
A convenient check for exhaust gas leakage into
cooling system is provided by a commercially avail-
able Block Leak Check tool. Follow manufacturers
instructions when using this product.
COMBUSTION LEAKAGE TEST - WITHOUT
PRESSURE TESTER
DO NOT WASTE reusable coolant. If solution is
clean, drain coolant into a clean container for reuse.
WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRESSURE.
SERIOUS BURNS FROM COOLANT CAN OCCUR.
Drain sufficient coolant to allow thermostat
removal. (Refer to 7 - COOLING/ENGINE/ENGINE
COOLANT THERMOSTAT - REMOVAL). Remove
Fig. 6 Pressure Testing Cooling SystemÐTypical
1 - TYPICAL COOLING SYSTEM PRESSURE TESTER
WJCOOLING 7 - 11
COOLING (Continued)
Page 235 of 2199

accessory drive belt (Refer to 7 - COOLING/ACCES-
SORY DRIVE/DRIVE BELTS - REMOVAL).
Add coolant to radiator to bring level to within 6.3
mm (1/4 in) of top of thermostat housing.
CAUTION: Avoid overheating. Do not operate
engine for an excessive period of time. Open drain-
cock immediately after test to eliminate boil over.
Start engine and accelerate rapidly three times, to
approximately 3000 rpm while observing coolant. If
internal engine combustion gases are leaking into
cooling system, bubbles will appear in coolant. If bub-
bles do not appear, internal combustion gas leakage
is not present.
DIAGNOSIS AND TESTING - COOLING SYSTEM
DEAERATION
As the engine operates, any air trapped in cooling
system gathers under the radiator cap. The next time
the engine is operated, thermal expansion of coolant
will push any trapped air past radiator cap into the
coolant reserve/overflow tank. Here it escapes to the
atmosphere into the tank. When the engine cools
down the coolant, it will be drawn from the reserve/
overflow tank into the radiator to replace any
removed air.
STANDARD PROCEDURE
STANDARD PROCEDUREÐDRAINING COOLING
SYSTEM 4.7L ENGINE
WARNING: DO NOT REMOVE THE CYLINDER
BLOCK DRAIN PLUGS (Fig. 7) OR LOOSEN THE
RADIATOR DRAINCOCK WITH SYSTEM HOT AND
UNDER PRESSURE. SERIOUS BURNS FROM
COOLANT CAN OCCUR.
(1) DO NOT remove radiator cap first. With engine
cold, raise vehicle on a hoist and locate radiator
draincock.
NOTE: Radiator draincock is located on the left/
lower side of radiator facing to rear of vehicle.
(2) Attach one end of a hose to the draincock. Put
the other end into a clean container. Open draincock
and drain coolant from radiator. This will empty the
coolant reserve/overflow tank. The coolant does not
have to be removed from the tank unless the system
is being refilled with a fresh mixture. When tank is
empty, remove radiator cap and continue draining
cooling system.
STANDARD PROCEDURE - REFILLING
COOLING SYSTEM 4.7L ENGINE
(1) Tighten the radiator draincock and the cylinder
block drain plug(s) (if removed).
CAUTION: Failure to purge air from the cooling sys-
tem can result in an overheating condition and
severe engine damage.
(2) Remove the cooling system bleed plug from the
radiator upper hose inlet housing. (Fig. 8)Fill system
using a 50/50 mixture of ethylene-glycol antifreeze
and low mineral content water, until coolant begains
coming out of the cooling system bleed hole. Install
the cooling system bleed plug. Fill radiator to top and
install radiator cap. Add sufficient coolant to the
reserve/overflow tank to raise level to FULL mark.
(3) With heater control unit in the HEAT position,
operate engine with radiator cap in place.
(4) After engine has reached normal operating
temperature, shut engine off and allow it to cool.
When engine is cooling down, coolant will be drawn
into the radiator from the reserve/overflow tank.
(5) Add coolant to reserve/overflow tank as neces-
sary.Only add coolant to the reserve/overflow
tank when the engine is cold. Coolant level in a
warm engine will be higher due to thermal
expansion.To purge the cooling system of all air,
this heat up/cool down cycle (adding coolant to cold
engine) must be performed three times. Add neces-
sary coolant to raise tank level to the FULL mark
after each cool down period.
Fig. 7 Drain PlugÐ4.7L Engine
1 - CYLINDER BLOCK DRAIN PLUG
2 - EXHAUST MANIFOLD AND HEAT SHIELD
7 - 12 COOLINGWJ
COOLING (Continued)
Page 250 of 2199

(1) Position sensor into the coolant recovery pres-
sure container (Fig. 1).
(2) Connect the coolant level sensor electrical con-
nector (Fig. 2).
(3) Close hood.
COOLANT RECOVERY PRESS
CONTAINER
DESCRIPTION
This system works along with the radiator pres-
sure cap. This is done by using thermal expansion
and contraction of the coolant to keep the coolant
free of trapped air. It provides:
²A volume for coolant expansion and contraction.
²A convenient and safe method for checking/ad-
justing coolant level at atmospheric pressure. This is
done without removing the radiator pressure cap.
²Some reserve coolant to the radiator to cover
minor leaks and evaporation or boiling losses.
As the engine cools, a vacuum is formed in the
cooling system of both the radiator and engine. Cool-
ant will then be drawn from the coolant tank and
returned to a proper level in the radiator.
The coolant reservoir/overflow system has a radia-
tor mounted pressurized cap, an overflow tube and a
plastic coolant reservoir/overflow tank (Fig. 3)
mounted to the right inner fender.
RADIATOR FAN - 4.7L
DESCRIPTION
The hydraulic fan (Fig. 4) used on vehicles
equipped the 4.7L engine, replaces both the electric
fan and the engine driven mechanical fan. The
hydraulic cooling fan is integral to the fan shroud
and is located between the radiator and the engine.
The power steering pump supplies the hydraulic
fluid and pressure to rotate the cooling fan blade,
while the electrical part of the fan is controlled by
the JTEC.
The hydraulic fan drive (motor) consists of the
three major following components:
²Steering flow control valve
Fig. 1 COOLANT LEVEL SENSOR ELECTRICAL
CONNECTOR
Fig. 2 COOLANT LEVEL SENSOR REMOVAL/
INSTALLATION
Fig. 3 Coolant Reservoir / Overflow Tank
1 - COOLANT OVERFLOW HOSE
2 - COOLANT RESERVOIR/OVERFLOW TANK
3 - COOLANT LEVEL SENSOR
4 - BOLT
WJENGINE 7 - 27
COOLANT LEVEL SENSOR (Continued)
Page 252 of 2199

NOTE: There is a steering flow control valve located
in the fan drive motor. This valve operates like the
flow control valve found in the typical power steer-
ing pump. Because of the design of the valve steer-
ing assist can not be effected by the radiator
cooling fan even during fan drive failure.
REMOVAL
(1) Raise vehicle on hoist.
(2) Drain cooling system.(Refer to 7 - COOLING -
STANDARD PROCEDURE)
NOTE: The hydraulic fan drive is driven by the
power steering pump. When removing lines or
hoses from fan drive assembly use a drain pan to
catch any power steering fluid that may exit the fan
drive or the lines and hoses.NOTE: When ever the high pressure line fittings are
removed from the hydraulic fan drive the O-rings
must be replaced.
(3) Disconnect two high pressure lines at hydraulic
fan drive (Fig. 6). Remove and discard o-rings from
line fittings.
(4) Disconnect low pressure return hose at hydrau-
lic fan drive (Fig. 6).
NOTE: The lower mounting bolts can only be
accessed from under vehicle.
(5) Remove two lower mounting bolts from the
shroud (Fig. 8).
(6) Lower vehicle.
(7) Disconnect the electrical connector for the fan
control solenoid.
(8) Disconnect the radiator upper hose at the radi-
ator and position out of the way.
(9) Disconnect the power steering gear outlet hose
and fluid return hose at the cooler (Fig. 7).
Fig. 5 HYDRAULIC FAN FLUID FLOW CIRCUIT
1 - POWER STEERING RESERVOIR
2 - POWER STEERING PUMP
3 - HYDRAULIC FAN DRIVE ASSEMBLY
4 - FAN BLADE5 - HYDRAULIC FAN CONTROL SOLENOID
6 - POWER STEERING OIL COOLER
7 - STEERING GEAR
WJENGINE 7 - 29
RADIATOR FAN - 4.7L (Continued)
Page 257 of 2199

(3) Raise vehicle.
(4) Remove engine cylinder block drain plug(s)
located on the sides of cylinder block above the oil
pan rail (Fig. 16).
(5) Remove power cord from block heater.(6) Loosen screw at center of block heater. Remove
heater assembly (Fig. 17).
REMOVALÐ4.0L ENGINE
(1) Disconnect negative battery cable from battery.
(2) Drain coolant from radiator (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(3) Raise vehicle.
(4) Remove engine cylinder block drain plug(s)
located on the sides of cylinder block above the oil
pan rail (Fig. 18).
(5) Remove power cord from block heater.
(6) Loosen screw at center of block heater. Remove
heater assembly (Fig. 19).
INSTALLATION
INSTALLATIONÐ4.7L ENGINE
(1) Thoroughly clean cylinder block core hole and
block heater seat.
(2) Insert block heater assembly with element loop
pointing at twelve o'clock (Fig. 17).
(3) With block heater fully seated, tighten center
screw to 2 N´m (17 in. lbs.) torque.
(4) Refill cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
(5) Start and warm the engine. Check for leaks.
INSTALLATIONÐ4.0L ENGINE
(1) Thoroughly clean cylinder block core hole and
block heater seat.
Fig. 15 Engine Block Heater 4.7L Engine
1 - ENGINE BLOCK HEATER
Fig. 16 Drain Plug - 4.7L Engine
1 - CYLINDER BLOCK DRAIN PLUG
2 - EXHAUST MANIFOLD AND HEAT SHIELD
Fig. 17 Engine Block Heater - 4.7L
1 - ENGINE BLOCK HEATER
7 - 34 ENGINEWJ
ENGINE BLOCK HEATER (Continued)
Page 325 of 2199

²Malfunction indicator lamp (Check engine lamp).
Driven through J1850 circuits.
²Overdrive indicator lamp (if equipped). Driven
through J1850 circuits.
²Oxygen sensor heater relays (if equipped).
²Radiator cooling fan relay (pulse width modu-
lated)
²Speed control source
²Speed control vacuum solenoid
²Speed control vent solenoid
²Tachometer (if equipped). Driven through J1850
circuits.
²Transmission convertor clutch circuit
²Transmission 3±4 shift solenoid
²Transmission relay
²Transmission temperature lamp (if equipped)
²Transmission variable force solenoid
OPERATION - 5 VOLT SUPPLIES
Primary 5±volt supply:
²supplies the required 5 volt power source to the
Crankshaft Position (CKP) sensor.
²supplies the required 5 volt power source to the
Camshaft Position (CMP) sensor.
²supplies a reference voltage for the Manifold
Absolute Pressure (MAP) sensor.
²supplies a reference voltage for the Throttle
Position Sensor (TPS) sensor.
Secondary 5±volt supply:
²supplies the required 5 volt power source to the
oil pressure sensor.
²supplies the required 5 volt power source for the
Vehicle Speed Sensor (VSS) (if equipped).
²supplies the 5 volt power source to the transmis-
sion pressure sensor (if equipped with an RE auto-
matic transmission).
OPERATION - IGNITION CIRCUIT SENSE
The ignition circuit sense input tells the PCM the
ignition switch has energized the ignition circuit.
Battery voltage is also supplied to the PCM
through the ignition switch when the ignition is in
the RUN or START position. This is referred to as
the9ignition sense9circuit and is used to9wake up9
the PCM.
REMOVAL
USE THE DRBIIItSCAN TOOL TO REPRO-
GRAM THE NEW POWERTRAIN CONTROL
MODULE (PCM) WITH THE VEHICLES ORIGI-
NAL IDENTIFICATION NUMBER (VIN) AND
THE VEHICLES ORIGINAL MILEAGE. IF THIS
STEP IS NOT DONE, A DIAGNOSTIC TROUBLE
CODE (DTC) MAY BE SET.
The PCM is located on the cowl panel in right/rear
side of engine compartment (Fig. 12).The PCM is located on the cowl panel in right/rear
side of engine compartment (Fig. 12).
To avoid possible voltage spike damage to PCM,
ignition key must be off, and negative battery cable
must be disconnected before unplugging PCM connec-
tors.
(1) Disconnect negative battery cable at battery.
Fig. 12 Powertrain Control Module (PCM) Location
1 - PCM
2 - COOLANT TANK
Fig. 13 Powertrain Control Module (PCM) 32±Way
Connectors
1 - 3 32±WAY CONNECTORS
2 - PCM/BRACKET ASSEMBLY
3 - BRACKET NUTS (3)
8E - 16 ELECTRONIC CONTROL MODULESWJ
POWERTRAIN CONTROL MODULE (Continued)
Page 355 of 2199

CHARGING
TABLE OF CONTENTS
page page
CHARGING
DESCRIPTION.........................24
OPERATION...........................24
DIAGNOSIS AND TESTING - CHARGING
SYSTEM............................24
SPECIFICATIONS
GENERATOR RATINGS - GAS POWERED . . 25
TORQUE - GAS POWERED.............25
SPECIAL TOOLS.......................26
BATTERY TEMPERATURE SENSOR
DESCRIPTION.........................26OPERATION...........................26
REMOVAL.............................26
INSTALLATION.........................26
GENERATOR
DESCRIPTION.........................27
OPERATION...........................27
REMOVAL.............................27
INSTALLATION.........................28
VOLTAGE REGULATOR
DESCRIPTION.........................28
OPERATION...........................28
CHARGING
DESCRIPTION
The charging system consists of:
²Generator
²Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
²Ignition switch
²Battery (refer to 8, Battery for information)
²Battery temperature sensor
²Generator Lamp (if equipped)
²Check Gauges Lamp (if equipped)
²Voltmeter (refer to 8, Instrument Cluster for
information)
²Wiring harness and connections (refer to 8, Wir-
ing for information)
OPERATION
The charging system is turned on and off with the
ignition switch. The system is on when the engine is
running and the ASD relay is energized. When the
ASD relay is on, voltage is supplied to the ASD relay
sense circuit at the PCM. This voltage is connected
through the PCM and supplied to one of the genera-
tor field terminals (Gen. Source +) at the back of the
generator.
The amount of DC current produced by the gener-
ator is controlled by the EVR (field control) circuitry
contained within the PCM. This circuitry is con-
nected in series with the second rotor field terminal
and ground.
A battery temperature sensor, located in the bat-
tery tray housing, is used to sense battery tempera-
ture. This temperature data, along with data from
monitored line voltage, is used by the PCM to vary
the battery charging rate. This is done by cycling theground path to control the strength of the rotor mag-
netic field. The PCM then compensates and regulates
generator current output accordingly.
All vehicles are equipped with On-Board Diagnos-
tics (OBD). All OBD-sensed systems, including EVR
(field control) circuitry, are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for certain failures it detects. Refer to
Diagnostic Trouble Codes in; Powertrain Control
Module; Electronic Control Modules for more DTC
information.
The Check Gauges Lamp (if equipped) monitors:
charging system voltage,engine coolant tempera-
ture and engine oil pressure. If an extreme condition
is indicated, the lamp will be illuminated. This is
done as reminder to check the three gauges. The sig-
nal to activate the lamp is sent via the CCD bus cir-
cuits. The lamp is located on the instrument panel.
Refer to 8, Instrument Cluster for additional infor-
mation.
DIAGNOSIS AND TESTING - CHARGING
SYSTEM
The following procedures may be used to diagnose
the charging system if:
²the check gauges lamp (if equipped) is illumi-
nated with the engine running
²the voltmeter (if equipped) does not register
properly
²an undercharged or overcharged battery condi-
tion occurs.
Remember that an undercharged battery is often
caused by:
²accessories being left on with the engine not
running
8F - 24 CHARGINGWJ