1995 JEEP YJ check engine

(5) Probe cavity B1 of cluster connector A. Check
for continuity to a good ground. There should be no
continuity. If OK, go to next step. If not OK, repair
short circuit as required.
(6) Still probing cavity B1 of cluster connector A,
check for continuity to cavity B of sending unit body
half connector. There should be continuity. If OK, re-
place gauge. If not OK, repair open circuit as re-
quired.
OIL PRESSURE GAUGE
The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is re-
lated to gauge accuracy, be certain to confirm that
problem is with gauge and not with engine oiling sys-
tem performance. Actual engine oil pressure should
be checked with a test gauge and compared to gauge
readings before you proceed with gauge diagnosis.
Refer to Group 9 - Engines for more information.
(1) Turn ignition switch to ON. Disconnect oil pres-
sure sending unit connector. The sending unit (Fig. 3)
is located on right side of engine block. On 2.5L en-
gine, it is just forward of ignition distributor and just
to the rear of generator mounting bracket. On 4.0L
engine, it is just to the rear of ignition distributor
and above oil filter adapter. The gauge needle should
move to high end of gauge scale. If OK, go to next
step. If not OK, go to step 3.
(2) Install a jumper wire from sending unit wiring
to ground. The gauge needle should move to low end
of gauge scale. If OK, replace sending unit. If not
OK, remove jumper wire and go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Disconnect instrument cluster con-
nector A.
(4) Probe cavity B7 (cavity B8 - RHD) of cluster
connector A. Check for continuity to a good ground.
There should be no continuity. If OK, go to next step.
If not OK, repair short circuit as required.(5) Still probing cavity B7 (cavity B8 - RHD) of
cluster connector A, check for continuity to sending
unit wire connector. There should be continuity. If
OK, replace gauge. If not OK, repair open circuit as
required.
SPEEDOMETER/ODOMETER
The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is re-
lated to gauge accuracy, be certain to confirm that
problem is with gauge and not with incorrect speed-
ometer pinion, axle ratio or tire size. Refer to Group
21 - Transmission and Transfer Case for more infor-
mation.
(1) Perform vehicle speed sensor test as described
in the appropriate Powertrain Diagnostic Procedures
manual. If OK, go to next step. If not OK, replace ve-
hicle speed sensor.
(2) Disconnect battery negative cable. Unplug vehi-
cle speed sensor, PCM, and daytime running lamp
module connectors. Remove instrument cluster bezel
and cluster assembly. Disconnect instrument cluster
connector A.
(3) Probe cavity A5 (cavity B6 - RHD) of cluster
connector A. Check for continuity to a good ground.
There should be no continuity. If OK, go to next step.
If not OK, repair short circuit as required.
(4) Still probing cavity A5 (cavity B6 - RHD) of
cluster connector A, check for continuity to cavity 1 of
vehicle speed sensor connector (Fig. 4). There should
be continuity. If OK, replace speedometer/odometer. If
not OK, repair open circuit as required.
TACHOMETER
(1) With engine running, check for tachometer sig-
nal at pin 43 of PCM connector (Fig. 5). See Tachom-
eter Calibration chart in Specifications. If OK, go to
next step. If not OK, replace PCM.
Fig. 2 Fuel Gauge Sending Unit ConnectorFig. 3 Oil Pressure Switch/Sending Unit - Typical
8E - 6 INSTRUMENT PANEL AND GAUGESÐXJJ

Connect battery negative cable and turn ignition
switch to ON. Lamp should light. If OK, repair open
circuit to brake warning switch. If not OK, replace
bulb.
(5) Turn ignition switch to OFF and remove
jumper wire. Disconnect battery negative cable.
Check for continuity between cavity A (cavity B -
RHD) of brake warning switch connector and a good
ground with ignition switch in START position.
There should be continuity. If not OK, go to next
step.
(6) Turn ignition switch to OFF and remove
jumper wire. Disconnect battery negative cable. Un-
plug ignition switch connector. Check for continuity
between ignition switch connector cavity 3 and a
good ground. There should be no continuity. If OK, go
to next step. If not OK, repair short circuit between
ignition switch and brake warning switch connectors
as required.
(7) Check for continuity between ignition switch
connector cavity 3 and brake warning switch connec-
tor cavity A (cavity B - RHD). There should be conti-
nuity. If OK, go to next step. If not OK, repair open
circuit as required.
(8) Check for continuity between metal steering
column jacket and a good ground. There should be
continuity. If OK, go to next step. If not OK, refer to
Group 19 - Steering to check steering column ground
clip installation.
(9) Turn ignition switch to START position and
hold there. Check for continuity between terminal 3
of ignition switch and a good ground. There should
be continuity. If not OK, replace ignition switch.
(10) Unplug brake warning switch connector.
Check for continuity between parking brake switch
connector and a good ground. There should be no
continuity. If OK, go to next step. If not OK, repair
short circuit as required.
(11) Check for continuity between parking brake
switch connector and cavity B (cavity A - RHD) of
brake warning switch connector. There should be
continuity. If OK, replace parking brake switch. If
not OK, repair open circuit to brake warning switch
as required.
COOLANT TEMPERATURE WARNING LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the problem being diagnosed is re-
lated to lamp accuracy, be certain to confirm that
problem is with lamp and not with cooling system
performance. Actual engine coolant temperature
should be checked with a test gauge or thermometer
before proceeding with lamp diagnosis. Refer to
Group 7 - Cooling System for more information.
(1) Turn ignition switch to START position. Lamp
should light. If OK, go to next step. If not OK, go to
step 3.(2) Turn ignition switch to ON. Disconnect coolant
temperature switch connector (Fig. 1). Jump switch
connector to ground. Lamp should light. If OK, re-
place switch. If not OK, go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Unplug coolant temperature switch
connector. Remove instrument cluster bezel and clus-
ter assembly. Disconnect cluster connector A and
probe cavity A1. Check for continuity to a good
ground. There should be no continuity. If OK, go to
next step. If not OK, repair short circuit to coolant
temperature switch or ignition switch as required.
(4) Connect cluster connector A to cluster. Install a
jumper wire from cavity A1 of cluster connector A to
a good ground. Connect battery negative cable and
turn ignition switch to ON. Lamp should light. If OK,
repair open circuit to coolant temperature switch or
ignition switch as required. If not OK, replace bulb.
FOUR-WHEEL DRIVE INDICATOR LAMPS
(1) Apply parking brake, start engine, vehicle in
4WD Lock or 4WD.
(2) Unplug switch and touch harness side of wire
to ground. Lamp should light. If OK, check switch
operation, replace if bad. If bulb is OK, repair open
to indicator.
GENERATOR WARNING LAMP
(1) Disconnect battery negative cable and unplug
PCM connector. Install a jumper wire between cavity
36 of PCM connector (Fig. 5) and a good ground. Con-
nect battery negative cable and turn ignition switch
to ON. Lamp should light. Unplug jumper wire and
lamp should go off. If OK, refer to Powertrain Diag-
nostic Procedures to check PCM. If not OK, go to
next step.
(2) Turn ignition switch to OFF and disconnect
battery negative cable. Remove instrument cluster
bezel and cluster assembly. Install a jumper wire be-
tween cavity B8 of cluster connector A and a good
ground. Connect battery negative cable and turn ig-
nition switch to ON. Lamp should light. If OK, go to
next step. If not OK, replace bulb.
(3) Turn ignition switch to OFF and disconnect
battery negative cable. Unplug cluster connector A.
Probe cavity B8 of cluster connector A and check for
continuity to a good ground. There should be no con-
tinuity. If OK, go to next step. If not OK, repair short
circuit as required.
(4) Check for continuity between cavity B8 of clus-
ter connector A and cavity 36 of PCM connector.
There should be continuity. If not OK, repair open
circuit as required.
HEADLAMP HIGH BEAM INDICATOR LAMP
(1) Check that headlamp high beams are func-
tional. If OK, go to next step. If not OK, refer to
Group 8L - Lamps for diagnosis of headlamp system.
JINSTRUMENT PANEL AND GAUGESÐXJ 8E - 13

(2) Disconnect battery negative cable. Remove in-
strument cluster bezel and cluster assembly. Unplug
cluster connector A. Connect battery negative cable.
Turn headlamps on and select high beam. Check for
battery voltage at cavity A4 of cluster connector A. If
OK, replace indicator bulb. If not OK, repair circuit
to headlamp dimmer (multi-function) switch as re-
quired.
LOW FUEL WARNING LAMP
(1) Check that fuel gauge is operating as designed.
See Fuel Gauge Calibration chart in Specifications. If
OK, go to next step. If not OK, see Fuel Gauge in
this section for diagnosis.
(2) With at least 10 gallons of fuel in fuel tank, un-
plug fuel tank sending unit connector. Turn ignition
switch to ON and wait 10 seconds. Lamp (LED)
should light. Reconnect fuel tank sending unit and
wait 20 seconds. Lamp (LED) should go off. If not
OK, replace low fuel warning lamp module.
LOW OIL PRESSURE WARNING LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the problem being diagnosed is re-
lated to lamp accuracy, be certain to confirm that
problem is with lamp and not with engine oiling sys-
tem. Actual engine oil pressure should be checked
with a test gauge before you proceed with lamp diag-
nosis. Refer to Group 9 - Engines for more informa-
tion.
(1) Turn ignition switch to ON. Lamp should light.
Start engine. Lamp should go off. If not OK, turn en-
gine off and go to next step.
(2) Unplug connector at oil pressure switch (Fig.
3). The switch is located on right side of engine block.
On 2.5L engine, it is just forward of ignition distrib-
utor and just to the rear of generator mounting
bracket. On 4.0L engine, it is just to the rear of igni-
tion distributor and above oil filter adapter. Install a
jumper wire from connector to a good ground. Turn
ignition switch to ON. Lamp should light. Unplug
jumper wire. Lamp should go out. If OK, replace oil
pressure switch. If not OK, go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Install a jumper wire from cavity
B7 (cavity B8 - RHD) of cluster connector A to a good
ground. Connect battery negative cable and turn ig-
nition switch to ON. Lamp should light. If OK, go to
next step. If not OK, replace lamp bulb.
(4) Turn ignition switch to OFF. Disconnect battery
negative cable. Unplug instrument cluster connector
A. Check continuity between cavity B7 (cavity B8 -
RHD) of cluster connector A and a good ground.
There should be no continuity. If OK, go to next step.
If not OK, repair short circuit as required.
(5) Check continuity between cavity B7 (cavity B8
- RHD) of cluster connector A and oil pressure switchconnector. There should be continuity. If not OK, re-
pair open circuit as required.
LOW WASHER FLUID WARNING LAMP
(1) Unplug washer fluid level switch connector.
Turn ignition switch to ON. Check for battery voltage
at connector cavity A. If OK, turn ignition switch to
OFF and go to next step. If not OK, repair open cir-
cuit to fuse F6 in PDC.
(2) Install a jumper wire from cavity A to cavity B
of washer fluid level switch connector. Turn ignition
switch to ON. Lamp should light. Unplug jumper and
lamp should go OFF. If OK, replace washer fluid
level switch. If not OK, go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Unplug instrument cluster (tell-
tale) connector B. Check continuity between cavity 16
(cavity 1 - RHD) of cluster connector B and a good
ground. There should be continuity. If OK, plug clus-
ter connector B back into cluster and go to next step.
If not OK, repair open circuit to ground as required.
(4) Connect battery negative cable. Install a
jumper wire from a 12-volt battery feed to cavity 1
(cavity 16 - RHD) of cluster connector B. Lamp
should light. If OK, go to next step. If not OK, re-
place bulb.
(5) Disconnect battery negative cable. Unplug clus-
ter connector B. Check continuity between cavity 1
(cavity 16 - RHD) of cluster connector B and a good
ground. There should be no continuity. If OK, go to
next step. If not OK, repair short circuit to switch as
required.
(6) Check continuity between cavity 1 (cavity 16 -
RHD) of cluster connector B and cavity B of washer
fluid level switch connector. There should be continu-
ity. If not OK, repair open circuit to switch as re-
quired.
MALFUNCTION INDICATOR LAMP
The diagnosis found here addresses an inoperative
lamp condition. If the lamp comes on and stays on
with engine running, refer to Group 14 - Fuel System
for diagnosis. If no fuel or emission system problem
is found, the following procedure will help locate a
short or open in the lamp circuit.
(1) Disconnect battery negative cable. Unplug PCM
connector. Install a jumper wire from cavity 32 of
PCM connector (Fig. 5) to a good ground. Connect
battery negative cable. Turn ignition switch to ON.
Lamp should light. Remove jumper wire and lamp
should go OFF. If OK, refer to Powertrain Diagnostic
Procedures to check PCM. If not OK, go to next step.
(2) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Install a jumper wire from cavity 2
(cavity 15 - RHD) of cluster (tell-tale) connector B to
a good ground. Connect battery negative cable. Turn
8E - 14 INSTRUMENT PANEL AND GAUGESÐXJJ

INSTRUMENT PANEL AND GAUGESÐYJ
CONTENTS
page page
INSTRUMENT PANEL AND GAUGESÐYJ..... 22
DIAGNOSIS............................ 23
GENERAL INFORMATION................. 20SERVICE PROCEDURES.................. 31
SPECIFICATIONS........................ 39
GENERAL INFORMATION
Following are general descriptions of major instru-
ment panel components. Refer to Group 8W - Wiring
Diagrams for complete circuit descriptions and dia-
grams.
INSTRUMENT PANEL
Modular instrument panel construction allows all
gauges and controls to be serviced from the front of
the panel. In addition, most instrument panel wiring
and heater components can be accessed without com-
plete instrument panel removal.
Removal of the left instrument cluster bezel allows
access to the main cluster assembly and most
switches. Removal of the center cluster bezel allows
access to the gauge package cluster assembly, the
heater controls, and the radio. Removal of the cluster
assemblies allows access to the individual gauges, il-
lumination and indicator lamp bulbs, printed cir-
cuits, and most wiring.
INSTRUMENT CLUSTERS
The instrument cluster used on YJ (Wrangler) mod-
els consists of two separate assemblies. The main
cluster assembly is located on the left side of the in-
strument panel, centered over the steering column
opening. The gauge package cluster assembly is lo-
cated near the center of the instrument panel. Each
cluster assembly is served by a separate printed cir-
cuit and wiring connector. Some variations of each
cluster exist due to optional equipment and regula-
tory requirements.
The main cluster assembly includes a speedometer/
odometer/trip odometer and a tachometer. It also in-
cludes provisions for the following indicator lamps:
²anti-lock brake system lamp
²brake warning lamp
²headlamp high beam indicator lamp
²malfunction indicator (Check Engine) lamp
²seat belt reminder lamp²turn signal indicator lamps
²upshift indicator lamp.
The gauge package cluster assembly includes a
four-wheel drive indicator lamp and the following
gauges:
²coolant temperature gauge
²fuel gauge
²oil pressure gauge
²voltmeter.
GAUGES
With the ignition switch in the ON or START posi-
tion, voltage is supplied to all gauges through the
two cluster printed circuits. With the ignition switch
in the OFF position, voltage is not supplied to the
gauges. A gauge pointer may remain within the
gauge scale after the ignition switch is OFF. How-
ever, the gauges do not accurately indicate any vehi-
cle condition unless the ignition switch is ON.
All gauges except the odometer are air core mag-
netic units. Two fixed electromagnetic coils are lo-
cated within the gauge. These coils are wrapped at
right angles to each other around a movable perma-
nent magnet. The movable magnet is suspended
within the coils on one end of a shaft. The gauge nee-
dle is attached to the other end of the shaft.
One of the coils has a fixed current flowing through
it to maintain a constant magnetic field strength.
Current flow through the second coil changes, which
causes changes in its magnetic field strength. The
current flowing through the second coil can be
changed by:
²a variable resistor-type sending unit (fuel level,
coolant temperature, or oil pressure)
²changes in electrical system voltage (voltmeter)
²electronic control circuitry (speedometer/odometer,
tachometer).
8E - 24 INSTRUMENT PANEL AND GAUGESÐYJJ

voltage is supplied to one side of the indicator bulb. A
ground path for the bulb is provided by 3 switches.
The bulb will light when:
²the brake warning switch is closed (indicating un-
equal brake system hydraulic pressures possibly due
to brake fluid leakage)
²the ignition switch is in the START position (bulb
test)
²the parking brake switch is closed (parking brake
is applied).
Refer to Group 5 - Brakes for more information.
FOUR-WHEEL DRIVE INDICATOR LAMP
This lamp lights when the transfer case is engaged
in the 4H or 4L position. Voltage is supplied to one
side of the indicator bulb. A switch on the front axle
disconnect housing is connected to the other side of
the indicator bulb. When the switch is closed, a path
to ground is provided and the indicator bulb lights.
HEADLAMP HIGH BEAM INDICATOR LAMP
The high beam indicator lamp is controlled by the
headlamp dimmer switch. One side of the indicator
bulb is grounded at all times. The other side of the
bulb receives battery feed through the contacts of the
dimmer switch when the turn signal switch lever is
actuated to turn the headlamp high beams on. Refer
to Group 8L - Lamps for more information.
MALFUNCTION INDICATOR LAMP
The CHECK ENGINE or Malfunction Indicator
Lamp (MIL) lights each time the ignition switch is
turned ON, and stays on for 3 seconds as a bulb test.
If the Powertrain Control Module (PCM) receives an
incorrect signal or no signal from certain fuel or
emission system related circuits or components, the
lamp is turned on. This will indicate that the PCM
has recorded a Diagnostic Trouble Code (DTC) in
electronic memory for a circuit or component mal-
function. Refer to Group 14 - Fuel System for more
information.
SEAT BELT REMINDER LAMP
The seat belt reminder lamp lights for 4 to 8 sec-
onds after the ignition switch is turned to the ON po-sition. A timer in the chime/buzzer module controls
ignition-switched battery feed to the lamp. Refer to
Group 8U - Chime/Buzzer Warning Systems for more
information.
TURN SIGNAL INDICATOR LAMPS
The left and right turn signal indicator lamps are
controlled by the turn signal and hazard warning
switches. One side of the bulb for each lamp is
grounded at all times. The other side of the bulb re-
ceives battery feed through the contacts of the turn
signal switch, when the turn signal lever or hazard
warning button are actuated. Refer to Group 8J -
Turn Signal and Hazard Warning Systems for more
information.
UPSHIFT INDICATOR LAMP
Vehicles equipped with manual transmissions have
an optional upshift indicator lamp. Ground feed for
the lamp is switched by the Powertrain Control Mod-
ule (PCM). The lamp lights to indicate when the
driver should shift to the next highest gear for best
fuel economy. The PCM will turn the lamp off after 3
to 5 seconds if the upshift is not performed. The lamp
will remain off until the vehicle stops accelerating
and is brought back to the range of lamp operation,
or until the transmission is shifted into another gear.
The indicator lamp is normally on when the igni-
tion switch is turned ON and is turned off when the
engine is started. The lamp will be turned on during
vehicle operation according to engine speed and load.
CLUSTER ILLUMINATION LAMPS
All cluster illumination lamps receive battery feed
from the instrument lamps fuse in the fuseblock
module through the panel dimmer switch. When the
park or headlamps are on, the cluster illumination
lamps light. Illumination brightness can be adjusted
by rotating the panel dimmer thumb-wheel, which is
next to the headlamp switch.
8E - 26 INSTRUMENT PANEL AND GAUGESÐYJJ

DIAGNOSIS
GAUGES
If an individual gauge is inoperative, see the diag-
nostic procedure under the heading for that gauge. If
more than one gauge in the main cluster or gauge
package cluster is inoperative, perform the following:
(1) Check fuse 9 in the fuseblock module. If OK, go
to next step. If not OK, replace fuse.
(2) Check for battery voltage at fuse 9 with igni-
tion switch in ON position. If OK, go to next step. If
not OK, repair open in circuit from ignition switch
and/or refer to Group 8D - Ignition Systems for test-
ing of ignition switch.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove the affected instrument clus-
ter bezel and cluster assembly. Disconnect the cluster
connector.
(4) Connect battery negative cable. Turn ignition
switch to ON. If problem is in main cluster, check for
battery voltage at cavity 3 and cavity 19 of main
cluster connector. If problem is in gauge package
cluster, check for battery voltage at cavity 2 and cav-
ity 12 of gauge package cluster connector. If OK, go
to next step. If not OK, repair open in circuit from
fuse 9 as required.
(5) Turn ignition switch to OFF. Disconnect battery
negative cable. Probe cavities 14 and 20 of main clus-
ter connector, or cavities 1 and 13 of gauge package
cluster connector. Check for continuity to a good
ground. There should be continuity. If OK, replace
the cluster printed circuit. If not OK, repair open in
circuit as required.
COOLANT TEMPERATURE GAUGE
The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is re-
lated to gauge accuracy, be certain to confirm that
problem is with gauge and not with cooling system
performance. Actual engine coolant temperature
should be checked with a test gauge or thermometer
and compared to gauge readings before you proceed
with gauge diagnosis. Refer to Group 7 - Cooling Sys-
tem for more information.
(1) Turn ignition switch to ON. Disconnect coolant
temperature sending unit connector. Sending unit
(Fig. 1) is located near left rear corner of the cylinder
head. The gauge needle should move to low end of
gauge scale. If OK, go to next step. If not OK, go to
step 3.
(2) Install a jumper wire from sending unit wiring
to ground. The gauge needle should move to high end
of gauge scale. If OK, replace sending unit. If not
OK, remove jumper wire and go to next step.(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove center instrument cluster be-
zel and gauge package cluster assembly. Disconnect
cluster connector.
(4) Probe cavity 11 of cluster connector. Check for
continuity to a good ground. There should be no con-
tinuity. If OK, go to next step. If not OK, repair short
in circuit as required.
(5) Still probing cavity 11 of cluster connector,
check for continuity to sending unit wiring connector.
There should be continuity. If OK, replace gauge. If
not OK, repair open in circuit as required.
FUEL GAUGE
The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is re-
lated to gauge accuracy, be certain to confirm that
problem is with gauge and not with fuel tank. In-
spect fuel tank for signs of damage or distortion that
could affect sending unit performance before you pro-
ceed with gauge diagnosis. Refer to Group 14 - Fuel
System for more information.
(1) Turn ignition switch to ON. Disconnect fuel
gauge sending unit connector. Connector is located
near the left front upper corner of fuel tank. The
gauge needle should move to high end of gauge scale.
If OK, go to next step. If not OK, go to step 4.
(2) Connect a jumper wire between terminals 1
and 2 in the body half of the fuel gauge sending unit
connector (Fig. 2). The gauge needle should move to
low end of gauge scale. If OK, refer to Group 14 -
Fuel System for procedure to replace sending unit. If
not OK, remove jumper wire and go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Check for continuity between termi-
nal 1 in the body half of fuel gauge sending unit con-
nector and a good ground. There should be
Fig. 1 Coolant Temperature Sending Unit - Typical
JINSTRUMENT PANEL AND GAUGESÐYJ 8E - 27

continuity. If OK, go to next step. If not OK, repair
circuit to ground as required.
(4) Remove center instrument cluster bezel and
gauge package cluster assembly. Disconnect cluster
connector.
(5) Probe cavity 6 of cluster connector. Check for
continuity to a good ground. There should be no con-
tinuity. If OK, go to next step. If not OK, repair short
circuit as required.
(6) Still probing cavity 6 of cluster connector, check
for continuity to cavity 2 of sending unit wiring body
half connector. There should be continuity. If OK, re-
place gauge. If not OK, repair open circuit as re-
quired.
OIL PRESSURE GAUGE
The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is re-
lated to gauge accuracy, be certain to confirm that
problem is with gauge and not with engine oiling sys-
tem performance. Actual engine oil pressure should
be checked with a test gauge and compared to gauge
readings before you proceed with gauge diagnosis.
Refer to Group 9 - Engines for more information.
(1) Turn ignition switch to ON. Disconnect oil pres-
sure sending unit connector. The sending unit (Fig. 3)
is located on right side of engine block. On 2.5L en-
gine, it is just forward of ignition distributor and just
to the rear of generator mounting bracket. On 4.0L
engine, it is just to the rear of ignition distributor
and above oil filter adapter. The gauge needle should
move to high end of gauge scale. If OK, go to next
step. If not OK, go to step 3.
(2) Install a jumper wire from sending unit wiring
to ground. The gauge needle should move to low end
of gauge scale. If OK, replace sending unit. If not
OK, remove jumper wire and go to next step.(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove center instrument cluster be-
zel and gauge package cluster assembly. Disconnect
cluster connector.
(4) Probe cavity 9 of cluster connector. Check for
continuity to a good ground. There should be no con-
tinuity. If OK, go to next step. If not OK, repair short
circuit as required.
(5) Still probing cavity 9 of cluster connector, check
for continuity to sending unit wire connector. There
should be continuity. If OK, replace gauge. If not OK,
repair open circuit as required.
SPEEDOMETER/ODOMETER
The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is re-
lated to gauge accuracy, be certain to confirm that
problem is with gauge and not with incorrect speed-
ometer pinion, axle ratio or tire size. Refer to Group
21 - Transmission and Transfer Case for more infor-
mation.
(1) Perform vehicle speed sensor test as described
in the appropriate Powertrain Diagnostic Procedures
manual. If OK, go to next step. If not OK, replace ve-
hicle speed sensor.
(2) Disconnect battery negative cable. Unplug vehi-
cle speed sensor, PCM, and daytime running lamp
module connectors. Remove left instrument cluster
bezel and main cluster assembly. Disconnect cluster
connector.
(3) Probe cavity 13 of cluster connector. Check for
continuity to a good ground. There should be no con-
tinuity. If OK, go to next step. If not OK, repair short
circuit as required.
(4) Still probing cavity 13 of cluster connector,
check for continuity to cavity 1 of vehicle speed sen-
sor connector (Fig. 4). There should be continuity. If
OK, replace speedometer/odometer. If not OK, repair
open circuit as required.
Fig. 2 Fuel Gauge Sending Unit ConnectorFig. 3 Oil Pressure Sending Unit - Typical
8E - 28 INSTRUMENT PANEL AND GAUGESÐYJJ

TACHOMETER
(1) With engine running, check for tachometer sig-
nal at pin 43 of PCM connector (Fig. 5). See Tachom-
eter Calibration chart in Specifications. If OK, go to
next step. If not OK, replace PCM.
(2) Disconnect battery negative cable. Unplug PCM
connector. Remove left instrument cluster bezel and
main cluster assembly. Disconnect cluster connector.
(3) Probe cavity 12 of cluster connector. Check for
continuity to a good ground. There should be no con-
tinuity. If OK, go to next step. If not OK, repair short
circuit as required.
(4) Still probing cavity 12 of cluster connector,
check for continuity to cavity 43 of PCM connector.
There should be continuity. If OK, replace tachome-
ter. If not OK, repair open circuit as required.
TRIP ODOMETER
If the trip odometer is inoperative, but the speed-
ometer/odometer functions are unaffected, replace
speedometer assembly. If speedometer/odometer func-
tions are affected, see Speedometer/Odometer diagno-
sis in this section.
VOLTMETER
(1) Turn ignition switch to ON. Voltmeter should
read battery voltage. If all gauges except voltmeter
are OK, go to next step. If other gauges are inopera-
tive, see Gauges in this section for diagnosis.
(2) Using an accurate test voltmeter, measure bat-
tery voltage at battery. Compare this reading to in-
strument cluster voltmeter reading. Now see
Voltmeter Calibration chart in Specifications. If volt-
meter does not perform to specification, replace volt-
meter.
Fig. 4 Vehicle Speed Sensor Connector
Fig. 5 Powertrain Control Module Connector
JINSTRUMENT PANEL AND GAUGESÐYJ 8E - 29