KNOCK SENSOR
DESCRIPTION
The knock sensor threads into the cylinder block.
The knock sensor is designed to detect engine vibra-
tion that is caused by detonation.
OPERATION
When the knock sensor detects a knock in one of
the cylinders, it sends an input signal to the PCM. In
response, the PCM retards ignition timing for all cyl-
inders by a scheduled amount.
Knock sensors contain a piezoelectric material
which constantly vibrates and sends an input voltage
(signal) to the PCM while the engine operates. As the
intensity of the crystal's vibration increases, the
knock sensor output voltage also increases.
The voltage signal produced by the knock sensor
increases with the amplitude of vibration. The PCM
receives as an input the knock sensor voltage signal.
If the signal rises above a predetermined level, the
PCM will store that value in memory and retard
ignition timing to reduce engine knock. If the knock
sensor voltage exceeds a preset value, the PCM
retards ignition timing for all cylinders. It is not a
selective cylinder retard.
The PCM ignores knock sensor input during engine
idle conditions. Once the engine speed exceeds a
specified value, knock retard is allowed.
Knock retard uses its own short term and long
term memory program.
Long term memory stores previous detonation
information in its battery-backed RAM. The maxi-
mum authority that long term memory has over tim-
ing retard can be calibrated.
Short term memory is allowed to retard timing up
to a preset amount under all operating conditions (as
long as rpm is above the minimum rpm) except WOT.
The PCM, using short term memory, can respond
quickly to retard timing when engine knock is
detected. Short term memory is lost any time the
ignition key is turned off.
NOTE: Over or under tightening affects knock sen-
sor performance, possibly causing improper spark
control.
REMOVAL
REMOVAL - 2.4L
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 12).
(1) Disconnect electrical connector from knock sen-
sor.(2) Use a crow foot socket to remove the knock
sensors.
REMOVAL - 3.8L
The knock sensor threads into the side of the cyl-
inder block in the rear.
(1) Disconnect the negative battery cable.
(2) Raise vehicle and support.
(3) On All Wheel Drive vehicles remove the PTU
(Power Transfer Unit), refer to the Transmission sec-
tion for more information.
(4) Disconnect electrical connector from knock sen-
sor.
(5) Use a crow foot socket to remove the knock
sensor.
INSTALLATION
INSTALLATION - 2.4L
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 12).
(1) Install knock sensor. Tighten knock sensor to
10 N´m (7 ft. lbs.) torque.Over or under tighten-
ing effects knock sensor performance, possibly
causing improper spark control.
(2) Attach electrical connector to knock sensor.
Fig. 12 Knock Sensor
1 - GENERATOR
2 - INTAKE MANIFOLD
3 - KNOCK SENSOR
4-STARTER
8I - 8 IGNITION CONTROLRS
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INSTRUMENT CLUSTER
TABLE OF CONTENTS
page page
INSTRUMENT CLUSTER
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - SELF-
DIAGNOSTICS.........................2
DIAGNOSIS AND TESTING - CLUSTER
DIAGNOSIS...........................2REMOVAL.............................10
INSTALLATION.........................10
CLUSTER LENS
REMOVAL.............................10
INSTALLATION.........................10
INSTRUMENT CLUSTER
DESCRIPTION
The instrumentation gauges are contained in a
subdial assembly within the instrument cluster. The
individual gauges are not serviceable. If one of the
cluster gauges becomes faulty, the entire cluster
would require replacement.
The Mechanical Instrument Cluster (MIC) with a
tachometer is equipped with a electronic vacuum flu-
orescent transmission range indicator (PRND3L),
odometer, and trip odometer display.
The MIC without a tachometer is equipped with a
Light Emitting Diode (LED) transmission range indi-
cator (PRND3L) and a vacuum fluorescent odometer
display.
The MIC is equipped with the following warning
lamps.
²Lift Gate Ajar
²Low Fuel Level
²Low Windshield Washer Fluid Level
²Cruise
²Battery Voltage
²Fasten Seat Belt
²Door Ajar
²Coolant Temperature
²Anti-Lock Brake
²Brake
²Oil Pressure
²MIL (Malfunction Indicator Lamp)
²VTSS/SKIS Indicator
²Airbag
²Traction Control
²Autostick
The MIC without a tachometer also has the follow-
ing warning lamps:
²Turns Signals
²High Beam
WATER IN FUEL LAMP - EXPORT
The Water In Fuel Lamp is located in the message
center. When moisture is found within the fuel sys-
tem, the sensor sends a message via the PCI data
bus to the instrument cluster. The MIC illuminates
the bulb in the message center, The sensor is located
underneath the vehicle, directly above the rear axle.
The sensor is housed within the fuel filter/water sep-
arator assembly cover. The sensor is not serviced sep-
arately. If found defective, the entire assembly cover
must be replaced.
OPERATION
Refer to the vehicle Owner's Manual for operation
instructions and conditions for the Instrument Clus-
ter Gauges.
WATER IN FUEL LAMP - EXPORT
The Water In Fuel Sensor is a resistive type
switch. It is calibrated to sense the different resis-
tance between diesel fuel and water. When water
enters the fuel system, it is caught in the bottom of
the fuel filter/water separator assembly, where the
sensor is located. Water has less resistance than die-
sel fuel. The sensor then sends a PCI data bus mes-
sage to the instrument cluster to illuminate the
lamp.
If the lamp is inoperative, perform the self diag-
nostic test on the instrument cluster to check the
lamp operation before continuing diagnosis.
RSINSTRUMENT CLUSTER8J-1
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FRONT FOG LAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery
cables.1. Clean and secure battery cable clamps and
posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of-charge. Refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical, Battery
System.
6. Poor lighting circuit Z349/Z248
ground.6. Test for voltage drop across Z349/248
ground locations. Refer to Electrical, Wiring
Information.
FOG LAMP BULBS
BURN OUT
FREQUENTLY1. Charging system output too
high.1. Test and repair charging system. Refer to
Electrical, Charging.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
FOG LAMPS ARE DIM
WITH ENGINE
RUNNING ABOVE IDLE1. Charging system output too low. 1. Test and repair charging system. Refer to
Electrical, Charging.
2. Poor lighting circuit Z349/Z248
ground.2. Test for voltage drop across Z349/Z248
ground locations. Refer to Electrical, Wiring
Information.
3. High resistance in fog lamp
circuit.3. Test amperage draw of fog lamp circuit.
FOG LAMPS FLASH
RANDOMLY1. Poor lighting circuit Z349/Z248
ground.1. Test for voltage drop across Z349/Z248
ground locations. Refer to Electrical, Wiring
Information.
2. Variable resistance in fog lamp
circuit.2. Test amperage draw of fog lamp circuit.
3. Faulty fog lamp switch (part of
headlamp switch).3. Replace headlamp switch.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
5. Is relay engaging properly? 5. Verify function of fog lamp relay in IPM.
6. PCI Bus Communication. 6. Verify PCI bus message (fog lamp info)
transmitted from BCM and received by FCM.
FOG LAMPS DO NOT
ILLUMINATE1. Blown fuse for fog lamp. 1. Replace fuse. Refer to Electrical, Wiring
Information.
2. No Z349/Z248 ground at fog
lamps.2. Repair circuit ground. Refer to Electrical,
Wiring Information.
3. Faulty fog lamp switch (part of
headlamp switch).3. Replace headlamp switch.
4. Broken connector terminal or
wire splice in fog lamp circuit.4. Repair connector terminal or wire splice.
5. Faulty or burned out bulb. 5. Replace bulb.
6. Is relay engaging? 6. Verify function of fog lamp relay in IPM.
7. PCI Bus Communication. 7. Verify PCI bus message (fog lamp info)
transmitted from BCM and received by FCM.
8L - 8 LAMPS/LIGHTING - EXTERIORRS
FRONT FOG LAMP (Continued)
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Before damaging a trim component, verify hidden
fasteners or captured edges are not holding the com-
ponent in place.
HEADLAMP DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery
cables.1. Clean and secure battery cable clamps and
posts.
2. Loose or worn generator drive
belt.2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system, refer to
Electrical, Charging
4. Battery has insufficient charge. 4. Test battery state-of-charge, refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery, refer to Electrical, Battery
System.
6. Poor lighting circuit Z343/Z344-
ground.6. Test for voltage drop across Z343/Z344-
ground locations, refer to Electrical, Wiring
Diagram Information.
HEADLAMP BULBS
BURN OUT
FREQUENTLY.1. Integrated Power Module (IPM)
not controlling voltage.1. Test and repair Integrated Power Module.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and splices.
Refer to Electrical, Wiring Information.
HEADLAMPS ARE DIM
WITH ENGINE
RUNNING ABOVE IDLE.1. Charging system output too low. 1. Test and repair charging system, refer to
Electrical, Wiring Information.
2. Poor lighting circuit Z343/Z344-
ground.2. Test for voltage drop across Z343/Z344-
ground locations, refer to Electrical, Wiring
Information.
3. High resistance in headlamp
circuit.3. Test amperage draw of headlamp circuit.
HEADLAMPS FLASH
RANDOMLY1. Poor lighting circuit Z343/Z344-
ground.1. Test for voltage drop across Z343/Z344-
ground locations, refer to Electrical, Wiring
Information.
2. Variable resistance in headlamp
circuit.2. Test amperage draw of headlamp circuit.
3. Loose or corroded terminals or
splices in circuit.3. Inspect and repair all connectors and splices,
refer to Electrical, Wiring Information.
4. Faulty headlamp switch. 4. Replace headlamp switch.
8L - 12 LAMPS/LIGHTING - EXTERIORRS
HEADLAMP (Continued)
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CONDITION POSSIBLE CAUSES CORRECTION
HEADLAMPS DO NOT
ILLUMINATE.1. No voltage to headlamps. 1. Repair open headlamp circuit, refer to
Electrical, Wiring Information.
2. No Z343/Z344-ground at
headlamps.2. Repair circuit ground, refer to Electrical,
Wiring Information.
3. Broken connector terminal or
wire splice in headlamp circuit.3. Repair connector terminal or wire splice.
4. Faulty or burned out bulb. 4. Replace headlamp bulb(s).
5. Body Control Module
malfunction.5. Refer to appropriate Body Control Module
diagnostics.
6. PCI Bus Communication 6. Verify messages being transmitted by BCM
and received by FCM.
7. IPM/FCM Malfunction. 7. Refer to appropriate IPM/FCM diagnostics.
HEADLAMPS ON WITH
IGNITION IN RUN, WITH
HEADLAMP SWITCH
OFF.1. Faulty headlamp switch. 1. Replace headlamp switch (review BCM
logged faults).
2. Diagnostic tool indicates (4.7 -
5.0V) on headlamp switch input to
BCM.2. Inspect and repair terminals, connectors and
open circuits.
3. PCI Bus Communication. 3. Verify messages being transmitted by BCM
and received by FCM.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove headlamp unit retaining screws.
(3) Remove headlamp unit to expose back of unit.
(4) Remove wiring connector from bulb.
(5) Rotate headlamp bulb retaining ring counter-
clockwise.
(6) Pull headlamp bulb and remove from headlamp
unit (Fig. 13).
INSTALLATION
(1) Install headlamp bulb to the headlamp unit.
(2) Install headlamp bulb retaining ring.
(3) Connect wiring connector to bulb.
(4) Install the headlamp unit.
(5) Install headlamp unit retaining screws.
(6) Reconnect the battery negative cable.
HEADLAMP - EXPORT
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the headlamp unit.
(3) Remove the cover (high beam lamp) or rubber
boot (low beam lamp) to access bulbs (Fig. 14).
(4) Disconnect the wire harness connector.
(5) Disengage spring clip from headlamp.
(6) Pull headlamp bulb from back of headlamp
unit.
INSTALLATION
(1) Insert headlamp bulb into headlamp unit.
(2) Engage spring clip to headlamp.
(3) Connect wire harness connector.
(4) Install the cover (high beam lamp) or rubber
boot (low beam lamp) to headlamp unit.
(5) Install the headlamp unit.
(6) Connect the battery negative cable.
Fig. 13 HEADLAMP
1 - HEADLAMP
2 - HEADLAMP UNIT
RSLAMPS/LIGHTING - EXTERIOR8L-13
HEADLAMP (Continued)
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HEADLAMP LEVELING MOTOR
- EXPORT
DIAGNOSIS AND TESTING - HEADLAMP
LEVELING MOTOR - EXPORT
HEADLAMP LEVELING MOTOR DIAGNOSIS
CONDITION POSSIBLE CAUSES CORRECTION
ONE MOTOR DOES NOT
OPERATE.1. Poor electrical connection at
motor1. Check for proper electrical connection at
motor
2. No voltage at motor 2. Repair no voltage condition. Refer to
Wiring Diagrams
3. No ground at motor 3. Repair no ground condition. Refer to
Wiring Diagrams
4. Defective motor 4. Replace leveling motor
BOTH MOTORS DO NOT
OPERATE1. No voltage at or from headlamp
leveling switch1. Repair no voltage condition. Check for
proper headlamp leveling switch operation
2. No voltage at leveling motors 2. Repair no voltage condition. Refer to
Wiring Diagrams
3. No ground at leveling motors 3. Repair no ground condition. Refer to
Wiring Diagrams
4. Both motors defective 4. Replace both motors
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove headlamp unit.(3) Disconnect electrical connector from headlamp
leveling motor.
(4) Remove the two mounting screws.
(5) Gently pry motor from headlamp unit (Fig. 15).
Fig. 14 HEADLAMP UNIT
1 - HIGH BEAM LAMP
2 - HEADLAMP LEVELING MOTOR
3 - LOW BEAM LAMP
4 - TURN LAMP
8L - 14 LAMPS/LIGHTING - EXTERIORRS
HEADLAMP - EXPORT (Continued)
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LAMP BULB
VOLTAGE INDICATOR LED
* VFD = VACUUM FLUORESCENT DISPLAY
CENTER CONSOLE LAMP
SWITCH
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Open console lid and remove tray.
(3) Using a flat bladed tool, pry up on the switch.
(4) Remove bulb from switch.
INSTALLATION
(1) Install bulb into switch.
(2) Push switch into console opening.
(3) Install tray and close lid.
(4) Connect battery negative cable.
CLUSTER ILLUMINATION
LAMPS
REMOVAL
(1) Remove the Instrument Cluster. Refer to Elec-
trical, Instrument Cluster, Removal.
(2) Turn over cluster and expose the illumination
bulb sockets.
(3) Identify which bulb is defective and twist it out
of the cluster using a counterclockwise motion.
INSTALLATION
(1) Install the new bulb socket into the cluster
using a clockwise motion.
(2) Install the Instrument Cluster. Refer to Electri-
cal, Instrument Cluster, Installation.
COURTESY LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Using a trim stick, pry lamp from door panel
(Fig. 1).
(3) Disconnect wire harness from the lamp.
(4) Remove lens from the lamp and remove bulb.
INSTALLATION
(1) Install bulb and lens to lamp.
(2) Reconnect wire harness to lamp.
(3) Press lamp into the door panel.(4) Reconnect battery negative cable.
DOME/CARGO LAMP
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Using a flat bladed tool, pry off the lamp lens.
(3) Remove bulb from lamp.
INSTALLATION
(1) Install bulb to lamp.
(2) Press lens into place.
(3) Connect battery negative cable.
GLOVE BOX LAMP SWITCH
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Open glove box door.
(3) Push switch through from behind (Fig. 2).
(4) Disconnect wire harness from switch.
(5) Pull bulb from switch.
INSTALLATION
(1) Push bulb into switch.
(2) Connect wire harness to switch.
(3) Push switch into instrument panel.
(4) Close glove box door.
(5) Reconnect the battery negative cable.
Fig. 1 COURTESY LAMP
1 - WIRE HARNESS
2 - COURTESY LAMP
8L - 26 LAMPS/LIGHTING - INTERIORRS
LAMPS/LIGHTING - INTERIOR (Continued)
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also affect compass operation. If the vehicle roof
should become magnetized, the demagnetizing and
calibration procedures found in this section may be
required to restore proper compass operation.
DESCRIPTION - TEMPERATURE
All the available overhead consoles on this model
include Temperature information. The temperature
displays the outside ambient temperature in whole
degrees. The temperature display can be toggled
from Fahrenheit to Celsius by selecting the desired
U.S./Metric option from the customer programmable
features. The displayed temperature is not an instant
reading of conditions, but an average temperature. It
may take the temperature display several minutes to
respond to a major temperature change, such as driv-
ing out of a heated garage into winter temperatures.
When the ignition switch is turned to the Off posi-
tion, the last displayed temperature reading stays in
the electronic control modules (CT, CMTC, EVIC)
memory. When the ignition switch is turned to the
On position again, the electronic module will display
the memory temperature for one minute; then update
the display to the current average temperature read-
ing within five minutes.
The temperature function is supported by an ambi-
ent temperature sensor. The sensor is mounted out-
side the passenger compartment near the front and
center of the vehicle, and is hard wired to the Front
Control Module (FCM). The FCM sends temperature
status messages to the module over the J1850 PCI
data bus circuit.
Following are general descriptions of the major
components used in the overhead console. Refer to
Wiring Diagrams for complete circuit schematics.
OPERATION
Refer to the vehicle Owner's Manual for specific
operation of each overhead console and its systems.
DIAGNOSIS AND TESTING - OVERHEAD
CONSOLE
If the problem with the overhead console is an
inaccurate or scrambled display, refer toSelf-Diag-
nostic Testbelow. If the problem with the overhead
console is incorrect Vacuum Fluorescent Display
(VFD) dimming levels, use a DRB IIItscan tool and
the proper Diagnostic Procedures manual to test for
the correct dimming message inputs being received
from the Body Control Module (BCM) or Front Con-
trol Module (FCM) over the J1850 Programmable
Communications Interface (PCI) data bus circuit. If
the problem is a no-display condition, use the follow-
ing procedures. For complete circuit diagrams, refer
toOverhead Consolein the Wiring Diagrams sec-
tion of the service manual.(1) Check the fused B(+) fuse in the integrated
power module. If OK, go to Step 2. If not OK, repair
the shorted circuit or component as required and
replace the faulty fuse.
(2) Check for battery voltage at the fused B(+) fuse
in the integrated power module. If OK, go to Step 3.
If not OK, repair the open fused B(+) circuit to the
fused B(+) fuse in the integrated power module as
required.
(3) Check the fused ignition switch output (run/
start) fuse in the integrated power module. If OK, go
to Step 4. If not OK, repair the shorted circuit or
component as required and replace the faulty fuse.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) fuse in the integrated power mod-
ule. If OK, go to Step 5. If not OK, repair the open
fused ignition switch output (run/start) circuit to the
ignition switch as required.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the overhead console. Check for continuity
between the ground circuit cavity of the roof wire
harness connector for the electronics module and a
good ground. There should be continuity. If OK, go to
Step 6. If not OK, repair the open ground circuit to
ground as required.
(6) Connect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
roof wire harness connector for the electronics mod-
ule. If OK, go to Step 7. If not OK, repair the open
fused B(+) circuit to the fused B(+) fuse in the inte-
grated power module as required.
(7)
Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run/start) circuit cavity of the roof wire har-
ness connector for the electronics module. If OK, refer
toSelf-Diagnostic Test
later this group for further
diagnosis of the electronics module and the J1850
PCI data bus circuit. If not OK, repair the open fused
ignition switch output (run/start) circuit to the fuse
in the integrated power module as required.
SELF-DIAGNOSTIC TEST
A self-diagnostic test is used to determine that the
electronics module is operating properly, and that all
the J1850 PCI data bus messages are being received
for initial operation. Initiate the self-diagnostic test
as follows:
(1) With the ignition switch in the Off position, on
Electronic Vehicle Information Center (EVIC) and
Compass Mini-Trip Computer (CMTC) equipped vehi-
cles simultaneously depress and hold theSTEP and
the RESET buttons. On Compass Temperature
Module (CT) equipped vehicles depress theC/T and
the US/M push buttons.
8M - 2 MESSAGE SYSTEMSRS
OVERHEAD CONSOLE (Continued)
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