2002 DODGE RAM check engine light

CONDITION POSSIBLE CAUSES CORRECTION
TEMPERATURE GAUGE READING
IS INCONSISTENT (FLUCTUATES,
CYCLES OR IS ERRATIC)1. During cold weather operation,
with the heater blower in the high
position, the gauge reading may
drop slightly.1. A normal condition. No correction
is necessary.
2. Temperature gauge or engine
mounted gauge sensor defective or
shorted. Also, corroded or loose
wiring in this circuit.2. Check operation of gauge and
repair if necessary. (Refer to 8 -
ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING).
3. Gauge reading rises when
vehicle is brought to a stop after
heavy use (engine still running)3. A normal condition. No correction
is necessary. Gauge should return
to normal range after vehicle is
driven.
4. Gauge reading high after
re-starting a warmed up (hot)
engine.4. A normal condition. No correction
is necessary. The gauge should
return to normal range after a few
minutes of engine operation.
5. Coolant level low in radiator (air
will build up in the cooling system
causing the thermostat to open
late).5. Check and correct coolant leaks.
(Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).
6. Cylinder head gasket leaking
allowing exhaust gas to enter
cooling system causing a
thermostat to open late.6. (a) Check for cylinder head
gasket leaks. (Refer to 7 -
COOLING - DIAGNOSIS AND
TESTING).
(b) Check for coolant in the engine
oil. Inspect for white steam emitting
from the exhaust system. Repair as
necessary.
7. Water pump impeller loose on
shaft.7. Check water pump and replace
as necessary. (Refer to 7 -
COOLING/ENGINE/WATER PUMP -
REMOVAL).
8. Loose accessory drive belt.
(water pump slipping)8. (Refer to 7 - COOLING/
ACCESSORY DRIVE/DRIVE BELTS
- DIAGNOSIS AND TESTING).
Check and correct as necessary.
9. Air leak on the suction side of
the water pump allows air to build
up in cooling system causing
thermostat to open late.9. Locate leak and repair as
necessary.
PRESSURE CAP IS BLOWING
OFF STEAM AND/OR COOLANT
TO COOLANT TANK.
TEMPERATURE GAUGE READING
MAY BE ABOVE NORMAL BUT
NOT HIGH. COOLANT LEVEL MAY
BE HIGH IN COOLANT RESERVE/
OVERFLOW TANK1. Pressure relief valve in radiator
cap is defective.1. Check condition of radiator cap
and cap seals. (Refer to 7 -
COOLING/ENGINE/RADIATOR
PRESSURE CAP - DIAGNOSIS
AND TESTING). Replace cap as
necessary.
7 - 10 COOLINGBR/BE
COOLING (Continued)

CLEANING
Clean radiator fins are necessary for good heat
transfer. The radiator and air conditioning fins
should be cleaned when an accumulation of debris
has occurred. With the engine cold, apply cold water
and compressed air to the back (engine side) of the
radiator to flush the radiator and/or A/C condenser of
debris.
INSPECTION
Inspect the radiator side tanks for cracks, broken
or missing fittings also inspect the joint where the
tanks seam up to the radiator core for signs of leak-
age and/or deteriorating seals.
Inspect radiator core for corroded, bent or missing
cooling fins. Inspect the core for bent or damaged
cooling tubes.
INSTALLATION
(1) Position fan shroud over the fan blades rear-
ward towards engine.
(2) Install rubber insulators to alignment dowels
at lower part of radiator.
(3) Lower the radiator into position while guiding
the two alignment dowels into lower radiator sup-
port. Different alignment holes are provided in the
lower radiator support for each engine application.
(4) Install two upper radiator mounting bolts.
Tighten bolts to 11 N´m (95 in. lbs.) torque.
(5) Connect both radiator hoses and install hose
clamps.
(6) Connect transmission cooler lines to radiator
tank. Inspect quick connect fittings for debris and
install until an audible ªclickº is heard. Pull apart to
verify connection.
(7) Install windshield washer reservoir tank.
(8) Position fan shroud to flanges on sides of radi-
ator. Install fan shroud mounting bolts (Fig. 41).
Tighten bolts to 6 N´m (50 in. lbs.) torque.
(9) Install metal clips to top of fan shroud.
(10) Install coolant reserve/overflow tank hose to
radiator filler neck nipple.
(11) Install coolant reserve/overflow tank to fan
shroud (fits into T-slots on shroud).
(12) Install battery negative cables.
(13) Install positive battery cable to top of radia-
tor. Tighten radiator-to-battery cable mounting nuts.
(14) Position heater controls tofull heatposition.
(15) Fill cooling system with coolant (Refer to 7 -
COOLING - STANDARD PROCEDURE).
(16) Operate engine until it reaches normal tem-
perature. Check cooling system and automatic trans-
mission (if equipped) fluid levels.
RADIATOR PRESSURE CAP
DESCRIPTION
Radiators are equipped with a pressure cap, which
releases pressure at some point within a range of
97-124 kPa (14-18 psi). The pressure relief point (in
pounds) is engraved on top of 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.
A rubber gasket seals radiator filler neck to pre-
vent leakage. This is done to keep system under
pressure. It also maintains vacuum during coolant
cool-down allowing coolant to return from reserve/
overflow tank.
OPERATION
The cap (Fig. 43) contains a spring-loaded pressure
relief valve that opens when system pressure reaches
release range of 97-124 kPa (14-18 psi).
A vent valve in the center of cap allows a small
coolant flow through cap when coolant is below boil-
ing temperature. The valve is completely closed when
boiling point is reached. As the coolant cools, it con-
tracts and creates a vacuum in the cooling system.
This causes the vacuum valve to open and coolant in
the reserve/overflow tank to be drawn through its
connecting hose into radiator. If the vacuum valve is
stuck shut, the radiator hoses will collapse on cool-
down. Clean the vent valve (Fig. 43).
Fig. 43 Radiator Pressure Cap and Filler NeckÐ
Typical
1 - STAINLESS-STEEL SWIVEL TOP
2 - RUBBER SEALS
3 - VENT VALVE
4 - RADIATOR TANK
5 - FILLER NECK
6 - OVERFLOW NIPPLE
7 - MAIN SPRING
8 - GASKET RETAINER
7 - 64 ENGINEBR/BE
RADIATOR - 5.9L DIESEL (Continued)

INSPECTION
Hold cap at eye level, right side up. The vent valve
(Fig. 45) at bottom of cap should open. If rubber gas-
ket has swollen and prevents vent valve from open-
ing, replace cap.
Hold cap at eye level, upside down. If any light can
be seen between vent valve and rubber gasket,
replace cap.Do not use a replacement cap that
has a spring to hold vent shut.A replacement cap
must be the type designed for a coolant reserve/over-
flow system with a completely sealed diaphragm
spring and a rubber gasket. This gasket is used to
seal to radiator filler neck top surface. Use of proper
cap will allow coolant return to radiator.
WATER PUMP - 5.9L
DESCRIPTION
The water pump is located on the engine front
cover, and has an integral pulley attached (Fig. 46).
The water pump impeller is pressed onto the rear
of a shaft that rotates in a bearing pressed into the
water pump body. The body has a small hole for ven-
tilation. The water pump seals are lubricated by
antifreeze in the coolant mixture. Additional lubrica-
tion is not necessary.
OPERATION
A centrifugal water pump circulates coolant
through the water jackets, passages, intake manifold,
radiator core, cooling system hoses and heater core,this coolant absorbs the heat generated when the
engine is running. The pump is driven by the engine
crankshaft via a drive belt.
DIAGNOSIS AND TESTINGÐWATER PUMP
A quick test to determine if pump is working is to
check if heater warms properly. A defective water
pump will not be able to circulate heated coolant
through the long heater hose to the heater core.
REMOVAL
The water pump on all models can be removed
without discharging the air conditioning system (if
equipped).
The water pump on all gas powered engines is
bolted directly to the engine timing chain case/cover.
On the 5.9L gas powered engine, a gasket is used
as a seal between the water pump and timing chain
case/cover.
If water pump is replaced because of bearing/shaft
damage or leaking shaft seal, the mechanical cooling
fan assembly should also be inspected. Inspect for
fatigue cracks, loose blades or loose rivets that could
have resulted from excessive vibration. Replace fan if
any of these conditions are found. Also check condi-
tion of the thermal viscous fan drive (Refer to 7 -
COOLING/ENGINE/FAN DRIVE VISCOUS
CLUTCH - DIAGNOSIS AND TESTING).
(1) Disconnect negative cable from battery.
(2) Drain cooling system (Refer to 7 - COOLING -
STANDARD PROCEDURE).
Do not waste reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.
Fig. 45 Radiator Pressure Cap
1 - STAINLESS-STEEL SWIVEL TOP
2 - RUBBER SEALS
3 - VENT VALVE
4 - RADIATOR TANK
5 - FILLER NECK
6 - OVERFLOW NIPPLE
7 - MAIN SPRING
8 - GASKET RETAINER
Fig. 46 Water Pump LocationÐTypical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
7 - 66 ENGINEBR/BE
RADIATOR PRESSURE CAP (Continued)

²Head/Park Lights-On Warning- The CTM
chime tone generator will generate repetitive chime
tones at a fast rate to announce that hard wired
inputs from the driver door ajar switch, headlamp
switch, and ignition switch indicate that the exterior
lamps are turned On with the driver side front door
opened and the ignition switch in the Off position.
The chimes will continue to sound until the exterior
lamps are turned Off, the driver side front door is
closed, or the ignition switch is turned to the On
position, whichever occurs first.
²Key-In-Ignition Warning- The CTM chime
tone generator will generate repetitive chime tones at
a fast rate to announce that hard wired inputs from
the driver door ajar switch, headlamp switch, and
ignition switch indicate that the key is in the ignition
lock cylinder with the driver side front door opened
and the ignition switch in the Off position. The
chimes will continue to sound until the key is
removed from the ignition lock cylinder, the driver
side front door is closed, or the ignition switch is
turned to the On position, whichever occurs first.
²Warning Chime Support- The CTM chime
tone generator will generate repetitive chime tones at
a slow rate to announce that a hard wired chime
request input has been received from the EMIC.
These chime tones provide an audible alert to the
vehicle operator that supplements certain visual indi-
cations displayed by the EMIC. Supplemented indica-
tions include the following:
²The ªAirbagº indicator is illuminated. The
chimes will continue to sound for a duration of about
four seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªCheck Gagesº indicator is illuminated. The
chimes will continue to sound for a duration of about
two seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªLow Fuelº indicator is illuminated. The
chimes will continue to sound for a duration of about
two seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªLow Washº indicator is illuminated. The
chimes will continue to sound for a duration of about
two seconds each time the indicator is illuminated or
until the ignition switch is turned to the Off position,
whichever occurs first.
²The ªTrans Tempº indicator is illuminated (auto-
matic transmission only). The chimes will continue to
sound for a duration of about two seconds each time
the indicator is illuminated or until the ignition
switch is turned to the Off position, whichever occurs
first.²The vehicle is over a programmed speed value
(Middle East Gulf Coast Country (GCC) only). The
CTM chime tone generator will generate repetitive
chime tones at a slow rate to announce that the vehi-
cle speed exceeds a programmed value. The chimes
will continue to sound until the vehicle speed is
below the programmed value.
²The ªWater-In-Fuelº indicator is illuminated
(diesel engine only). The chimes will continue to
sound for a duration of about two seconds each time
the indicator is illuminated or until the ignition
switch is turned to the Off position, whichever occurs
first.
The CTM provides chime service for all available
features in the chime warning system. The CTM
relies upon hard wired inputs from the driver door
ajar switch, the EMIC, the headlamp switch, and the
key-in ignition switch (ignition switch) to provide
chime service for all of the chime warning system
features. Upon receiving the proper inputs, the CTM
activates the integral chime tone generator to pro-
vide the audible chime tone to the vehicle operator.
The chime tone generator in the CTM is capable of
producing repeated chime tones at two different
rates, slow or fast. The slow chime rate is about fifty
chime tones per minute, while the fast chime rate is
about 180 chime tones per minute. The internal pro-
gramming of the CTM and the EMIC determines the
priority of each chime tone request input that is
received, as well as the rate and duration of each
chime tone that is to be generated.
The hard wired chime warning system inputs to
the CTM and the EMIC, as well as other hard wired
circuits for this system may be diagnosed and tested
using conventional diagnostic tools and procedures.
See the owner's manual in the vehicle glove box for
more information on the features provided by the
chime warning system.
DIAGNOSIS AND TESTING - CHIME WARNING
SYSTEM
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 har-
ness connectors, splices and grounds. The hard wired
chime warning system inputs to the Central Timer
Module (CTM) and the Electro-Mechanical Instru-
ment Cluster (EMIC), as well as other hard wired
circuits for this system may be diagnosed and tested
using conventional diagnostic tools and procedures.
8B - 2 CHIME/BUZZERBR/BE
CHIME WARNING SYSTEM (Continued)

INSTALLATION
If engine has been cranked while distributor is
removed, establish the relationship between distribu-
tor shaft and number one piston position as follows:
Rotate crankshaft in a clockwise direction, as
viewed from front, until number one cylinder piston
is at top of compression stroke (compression should
be felt on finger with number one spark plug
removed). Then continue to slowly rotate engine
clockwise until indicating mark (Fig. 18) is aligned to
0 degree (TDC) mark on timing chain cover.
(1) Clean top of cylinder block for a good seal
between distributor base and block.
(2) Lightly oil the rubber o-ring seal on the distrib-
utor housing.
(3) Install rotor to distributor shaft.
(4) Position distributor into engine to its original
position. Engage tongue of distributor shaft with slot
in distributor oil pump drive gear. Position rotor to
the number one spark plug cable position.
(5) Install distributor holddown clamp and clamp
bolt. Do not tighten bolt at this time.
(6) Rotate the distributor housing until rotor is
aligned to CYL. NO. 1 alignment mark on the cam-
shaft position sensor (Fig. 19).(7) Tighten clamp holddown bolt (Fig. 20) to 22.5
N´m (200 in. lbs.) torque.
(8) Connect camshaft position sensor wiring har-
ness to main engine harness.
(9) Install distributor cap. Tighten mounting
screws.
(10) Refer to the following, Checking Distributor
Position.
Checking Distributor Position
To verify correct distributor rotational position, the
DRB scan tool must be used.
WARNING: WHEN PERFORMING THE FOLLOWING
TEST, THE ENGINE WILL BE RUNNING. BE CARE-
FUL NOT TO STAND IN LINE WITH THE FAN
BLADES OR FAN BELT. DO NOT WEAR LOOSE
CLOTHING.
(1) Connect DRB scan tool to data link connector.
The data link connector is located in passenger com-
partment, below and to left of steering column.
(2) Gain access to SET SYNC screen on DRB.
(3) Follow directions on DRB screen and start
engine. Bring to operating temperature (engine must
be in ªclosed loopº mode).
(4) With engine running atidle speed, the words
IN RANGE should appear on screen along with 0É.
This indicates correct distributor position.
(5) If a plus (+) or a minus (-) is displayed next to
degree number, and/or the degree displayed is not
zero, loosen but do not remove distributor holddown
clamp bolt. Rotate distributor until IN RANGE
appears on screen. Continue to rotate distributor
until achieving as close to 0É as possible. After
adjustment, tighten clamp bolt to 22.5 N´m (200 in.
lbs.) torque.
The degree scale on SET SYNC screen of DRB is
referring to fuel synchronization only.It is not
referring to ignition timing.Because of this, do
not attempt to adjust ignition timing using this
method. Rotating distributor will have no effect on
ignition timing. All ignition timing values are con-
trolled by powertrain control module (PCM).
After testing, install air cleaner assembly.
Fig. 20 Distributor Holddown Clamp
1 - CLAMP BOLT
2 - HOLDDOWN CLAMP
3 - DISTRIBUTOR HOUSING
BR/BEIGNITION CONTROL 8I - 13
DISTRIBUTOR (Continued)

CAUTION: Do not leave any one spark plug cable
disconnected for longer than necessary during test-
ing. This may cause possible heat damage to the
catalytic converter. Total test time must not exceed
ten minutes.
With the engine running, remove spark plug cable
from spark plug (one at a time) and hold next to a
good engine ground. If the cable and spark plug are
in good condition, the engine rpm should drop and
the engine will run poorly. If engine rpm does not
drop, the cable and/or spark plug may not be operat-
ing properly and should be replaced. Also check
engine cylinder compression.
With the engine not running, connect one end of a
test probe to a good ground. Start the engine and run
the other end of the test probe along the entire
length of all spark plug cables. If cables are cracked
or punctured, there will be a noticeable spark jump
from the damaged area to the test probe. The cable
running from the ignition coil to the distributor cap
can be checked in the same manner. Cracked, dam-
aged or faulty cables should be replaced with resis-
tance type cable. This can be identified by the words
ELECTRONIC SUPPRESSION printed on the cable
jacket.
Use an ohmmeter to test for open circuits, exces-
sive resistance or loose terminals. If equipped,
remove the distributor cap from the distributor.Do
not remove cables from cap.Remove cable from
spark plug. Connect ohmmeter to spark plug termi-
nal end of cable and to corresponding electrode in
distributor cap. Resistance should be 250 to 1000
Ohms per inch of cable. If not, remove cable from dis-
tributor cap tower and connect ohmmeter to the ter-
minal ends of cable. If resistance is not within
specifications as found in the SPARK PLUG CABLE
RESISTANCE chart, replace the cable. Test all spark
plug cables in this manner.
SPARK PLUG CABLE RESISTANCE
MINIMUM MAXIMUM
250 Ohms Per Inch 1000 Ohms Per Inch
3000 Ohms Per Foot 12,000 Ohms Per Foot
To test ignition coil-to-distributor cap cable, do not
remove the cable from the cap. Connect ohmmeter to
rotor button (center contact) of distributor cap and
terminal at ignition coil end of cable. If resistance is
not within specifications as found in the Spark Plug
Cable Resistance chart, remove the cable from the
distributor cap. Connect the ohmmeter to the termi-
nal ends of the cable. If resistance is not within spec-
ifications as found in the Spark Plug CableResistance chart, replace the cable. Inspect the igni-
tion coil tower for cracks, burns or corrosion.
REMOVAL
CAUTION: When disconnecting a high voltage cable
from a spark plug or from the distributor cap, twist
the rubber boot slightly (1/2 turn) to break it loose
(Fig. 37). Grasp the boot (not the cable) and pull it
off with a steady, even force.
INSTALLATION
Install cables into the proper engine cylinder firing
order (Fig. 38) or (Fig. 39).
Fig. 37 Cable Removal
1 - SPARK PLUG CABLE AND BOOT
2 - SPARK PLUG BOOT PULLER
3 - TWIST AND PULL
4 - SPARK PLUG
Fig. 38 Engine Firing OrderÐ5.9L V-8 Engines
BR/BEIGNITION CONTROL 8I - 21
SPARK PLUG CABLE (Continued)

on the instrument cluster circuit board based upon a
hard wired input to the instrument cluster, cluster
programming, and electronic messages received by
the cluster from the Controller Antilock Brake (CAB)
over the Chrysler Collision Detection (CCD) data bus.
The brake indicator Light Emitting Diode (LED)
receives battery current on the instrument cluster
electronic circuit board through the fused ignition
switch output (st-run) circuit whenever the ignition
switch is in the On or Start positions; therefore, the
LED will always be off when the ignition switch is in
any position except On or Start. The LED only illu-
minates when it is provided a path to ground by the
instrument cluster transistor. The instrument cluster
will turn on the brake indicator for the following rea-
sons:
²Bulb Test- Each time the ignition switch is
turned to the On position the brake indicator is illu-
minated by the instrument cluster for about four sec-
onds as a bulb test.
²Park Brake-On- If the park brake is applied
or not fully released with the ignition switch in the
On position, the brake indicator is illuminated solid.
The brake indicator will blink on and off repeatedly
when the park brake is applied or not fully released
and the ignition switch is in the On position if a
vehicle with an automatic transmission is not in
Park or Neutral, or if the engine is running on vehi-
cles with a manual transmission.
²Brake Lamp-On Message- Each time the
cluster receives a lamp-on message from the CAB,
the brake indicator will be illuminated. The indicator
remains illuminated until the cluster receives a
lamp-off message from the CAB, or until the ignition
switch is turned to the Off position, whichever occurs
first.
²Actuator Test- Each time the instrument clus-
ter is put through the actuator test, the brake indi-
cator will be turned on during the bulb check portion
of the test to confirm the functionality of the LED
and the cluster control circuitry.
The park brake switch on the park brake pedal
mechanism provides a hard wired ground input to
the instrument cluster circuitry through the park
brake switch sense circuit whenever the park brake
is applied or not fully released. The CAB continually
monitors the brake pressure switch on the brake
combination valve to determine if the pressures in
the two halves of the split brake hydraulic system
are unequal. The CAB then sends the proper lamp-on
or lamp-off messages to the instrument cluster. If the
CAB sends a lamp-on message after the bulb test, it
indicates that the CAB has detected a brake hydrau-
lic system malfunction and/or that the ABS system
has become inoperative. The CAB will store a Diag-
nostic Trouble Code (DTC) for any malfunction itdetects. The park brake switch input to the instru-
ment cluster can be diagnosed using conventional
diagnostic tools and methods. For proper diagnosis of
the antilock brake system, the CAB, the CCD data
bus, or the message inputs to the instrument cluster
that control the brake indicator, a DRBIIItscan tool
is required. Refer to the appropriate diagnostic infor-
mation.
DIAGNOSIS AND TESTING - BRAKE INDICATOR
The diagnosis found here addresses an inoperative
brake indicator condition. If the brake indicator
comes on or stays on with the ignition switch in the
On position and the park brake released, or comes on
while driving, the brake system must be diagnosed
and repaired prior to performing the following tests.
(Refer to 5 - BRAKES - DIAGNOSIS AND TEST-
ING). If no brake system problem is found, the fol-
lowing procedure will help locate a faulty park brake
switch or park brake switch sense circuit. Refer to
the appropriate wiring information. The wiring infor-
mation includes wiring diagrams, proper wire and
connector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
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. Disconnect the instrument panel wire harness
connector for the park brake switch from the switch
terminal. With the park brake released, check for
continuity between the park brake switch terminal
and a good ground. There should be no continuity. If
OK, go to Step 2. If not OK, adjust or replace the
faulty park brake switch.
(2) Remove the instrument cluster from the instru-
ment panel. With the park brake switch still discon-
nected, check for continuity between the park brake
switch sense circuit cavity of the instrument panel
wire harness connector for the park brake switch and
a good ground. There should be no continuity. If OK,
go to Step 3. If not OK, repair the shorted park
8J - 16 INSTRUMENT CLUSTERBR/BE
BRAKE/PARK BRAKE INDICATOR (Continued)

brake switch sense circuit between the park brake
switch and the instrument cluster as required.
(3) Check for continuity between the park brake
switch sense circuit cavities of the instrument panel
wire harness connector for the park brake switch and
the instrument panel wire harness connector (Con-
nector C1) for the instrument cluster. There should
be continuity. If OK, proceed with diagnosis of the
instrument cluster. (Refer to 8 - ELECTRICAL/IN-
STRUMENT CLUSTER - DIAGNOSIS AND TEST-
ING). If not OK, repair the open park brake switch
sense circuit between the park brake switch and the
instrument cluster as required.
CHECK GAUGES INDICATOR
DESCRIPTION
A check gauges indicator is standard equipment on
all instrument clusters. The check gauges indicator is
located on the lower edge of the instrument cluster
overlay, to the right of center. The check gauges indi-
cator consists of a stenciled cutout of the words
ªCHECK GAGESº in the opaque layer of the instru-
ment cluster overlay. The dark outer layer of the
overlay prevents the indicator from being clearly vis-
ible when it is not illuminated. A red lens behind the
cutout in the opaque layer of the overlay causes the
ªCHECK GAGESº text to appear in red through the
translucent outer layer of the overlay when the indi-
cator is illuminated from behind by a Light Emitting
Diode (LED) soldered onto the instrument cluster
electronic circuit board. The check gauges indicator is
serviced as a unit with the instrument cluster.
OPERATION
The check gauges indicator gives an indication to
the vehicle operator when certain instrument cluster
gauge readings reflect a condition requiring immedi-
ate attention. This indicator is controlled by a tran-
sistor on the instrument cluster circuit board based
upon the cluster programming and electronic mes-
sages received by the cluster from the Powertrain
Control Module (PCM) over the Chrysler Collision
Detection (CCD) data bus. The check gauges indica-
tor Light Emitting Diode (LED) receives battery cur-
rent on the instrument cluster electronic circuit
board through the fused ignition switch output (st-
run) circuit whenever the ignition switch is in the On
or Start positions; therefore, the LED will always be
off when the ignition switch is in any position except
On or Start. The LED only illuminates when it is
provided a path to ground by the instrument cluster
transistor. The instrument cluster will turn on the
check gauges indicator for the following reasons:²Bulb Test- Each time the ignition switch is
turned to the On position the check gauges indicator
is illuminated for about two seconds as a bulb test.
²Engine Temperature High Message- Each
time the cluster receives a message from the PCM
indicating the engine coolant temperature of a gaso-
line engine is about 122É C (253É F) or higher, or a
diesel engine is about 112É C (233É F) or higher, the
check gauges indicator will be illuminated. The indi-
cator remains illuminated until the cluster receives a
message from the PCM indicating that the tempera-
ture of a gasoline engine is about 119É C (246É F) or
lower, a diesel engine is about 109É C (226É F) or
lower, or until the ignition switch is turned to the Off
position, whichever occurs first.
²Engine Oil Pressure Low Message- Each
time the cluster receives a message from the PCM
indicating the engine oil pressure of a gasoline
engine is about 3.45 kPa (0.5 psi) or lower, or a diesel
engine is about 51.71 kPa (7.5 psi) or lower, the
check gauges indicator will be illuminated. The indi-
cator remains illuminated until the cluster receives a
message from the PCM indicating that the engine oil
pressure of a gasoline engine is above 3.45 kPa (0.5
psi), a diesel engine is above 51.71 kPa (7.5 psi), or
until the ignition switch is turned to the Off position,
whichever occurs first. The cluster will only turn the
indicator on in response to an engine oil pressure low
message if the engine speed is greater than zero.
²System Voltage Low Message- Each time the
cluster receives a message from the PCM indicating
the electrical system voltage is less than 11.5 volts,
the check gauges indicator will be illuminated. The
indicator remains illuminated until the cluster
receives a message from the PCM indicating the elec-
trical system voltage is greater than 12.0 volts (but
less than 16.6 volts), or until the ignition switch is
turned to the Off position, whichever occurs first.
²System Voltage High Message- Each time
the cluster receives a message from the PCM indicat-
ing the electrical system voltage is greater than 16.6
volts, the check gauges indicator will be illuminated.
The indicator remains illuminated until the cluster
receives a message from the PCM indicating the elec-
trical system voltage is less than 16.1 volts (but
greater than 11.5 volts), or until the ignition switch
is turned to the Off position, whichever occurs first.
²Actuator Test- Each time the cluster is put
through the actuator test, the indicator will be
turned on during the bulb check portion of the test to
confirm the functionality of the LED and the cluster
control circuitry.
The PCM continually monitors the engine temper-
ature, oil pressure, and electrical system voltage,
then sends the proper messages to the instrument
cluster. For further diagnosis of the check gauges
BR/BEINSTRUMENT CLUSTER 8J - 17
BRAKE/PARK BRAKE INDICATOR (Continued)