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Page 481 of 2627

dimmer controlled back lighting of the switch when
the headlamps or park lamps are on.
The heated seat switches are both mounted in the
instrument panel center bezel, located in the lower
center of the instrument panel. The two switches are
snapped into the mounting holes of the heated seat
switch bezel, and the heated seat switch bezel is
secured with screws to the instrument panel center
bezel. The heated seat switches are differentiated by
the keyway in the connector receptacle on the backs
of the switches and keyway on the switch housing.
The instrument panel wire harness connectors for
the heated seat switches are keyed to match the con-
nector receptacles on the switches so that the two
heated seat switches can only be connected to the
proper heated seat electrical.
The two LED indicator lamps and the incandescent
bulb in each heated seat switch cannot be repaired. If
the indicator lamps or back lighting bulb are faulty
or damaged, the individual heated seat switch must
be replaced.
OPERATION
The heated seat switches receive battery current
through a fused ignition switch output (run) circuit
when the ignition switch is in the On position.
Depressing the heated seat switch rocker to its
momentary High or Low position provides a hard-
wired resistance signal to the heated seat module.
This signal tells the module to energize the heatedseat element of the selected seat and maintain the
requested temperature setting. If the heated seat
switch is depressed to a different position (Low or
High) than the currently selected state, the heated
seat module will change states to support the new
selection. If a heated seat switch is depressed a sec-
ond time, the heated seat module interprets the sec-
ond input as a request to turn the seat heater OFF.
The High and Low LED indicator lamps in the
heated seat switches receive battery current through
a fused ignition switch output (run) circuit when the
ignition switch is in the On position. The ground side
of each indicator lamp is controlled by the heated
seat module. This control of the switch indicator
lamps also allows the module to provide diagnostic
feedback to the vehicle operator or technician to indi-
cate heated seat system faults by flashing the indica-
tor lamps on and off. One side of the incandescent
back lighting bulb in each heated seat switch is con-
nected to ground at all times. The other side of the
incandescent bulb is connected to the fused panel
lamps dimmer switch signal circuit. These bulbs are
energized when the park lamps or headlamps are
turned on, and their illumination intensity is con-
trolled by the panel lamps dimmer switch.
DIAGNOSIS AND TESTING - HEATED SEAT
SWITCH
Refer toWiring Diagramsfor connector pin-outs
and the location of complete heated seat system wir-
ing diagrams.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT AND ISOLATE THE BATTERY NEGATIVE
(GROUND) CABLE, THEN WAIT TWO MINUTES FOR
THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE
BEFORE PERFORMING FURTHER DIAGNOSIS OR
SERVICE. THIS IS THE ONLY SURE WAY TO DIS-
ABLE THE AIRBAG SYSTEM. FAILURE TO TAKE
THE PROPER PRECAUTIONS COULD RESULT IN
ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
(1) If the problem being diagnosed involves inoper-
ative heated seat switch back lighting and the cluster
illumination lamps operate, go to Step 2. If the prob-
lem being diagnosed involves inoperative heated seat
switch back lighting and the cluster illumination
lamps are also inoperative, (Refer to 8 - ELECTRI-
CAL/INSTRUMENT CLUSTER - DIAGNOSIS AND
TESTING). If the problem being diagnosed involves
inoperative heated seat switch indicator lamps and
the heated seat elements do not heat, proceed. If the
Fig. 4 HEATED SEAT SWITCH
1 - HEATED SEAT SWITCH
2 - LIGHT-EMITTING DIODE (LED) INDICATOR LAMPS
8G - 12 HEATED SEAT SYSTEMDR
HEATED SEAT SWITCH (Continued)
Page 482 of 2627

problem being diagnosed involves inoperative heated
seat switch indicator lamps and the heated seat ele-
ments do heat, go to Step 6. If the problem being
diagnosed involves a heated seat switch indicator
lamp that remains illuminated after the heated seat
has been turned Off, (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/MEMORY
HEATED SEAT/MIRROR MODULE - DIAGNOSIS
AND TESTING).
(2) Disconnect and isolate the battery negative
cable. Remove the heated seat switch and bezel unit
from the instrument panel. Disconnect the heated
seat switch to be tested. Check for continuity
between the ground circuit cavity of the heated seat
switch and a good ground. There should be continu-
ity. If OK, go to Step 3. If not OK, repair the open
ground circuit to ground as required.
(3) Reconnect the battery negative cable. Turn the
park lamps on with the headlamp switch. Rotate the
panel lamps dimmer thumb wheel on the headlamp
switch upward to just before the interior lamps
detent. Check for battery voltage at the fused panel
lamps dimmer circuit cavity of the heated seat
switch. If OK, go to Step 4. If not OK, repair the
open fused panel lamps dimmer switch signal circuit
to the fuse in the Integrated Power Module as
required.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run) circuit cavity of the heated seat switch.
If OK, go to Step 5. If not OK, repair the open fused
ignition switch output (run) circuit as required.
(5) Check the continuity and resistance values of
the heated seat switch in the Neutral, Low and High
positions as shown in the Heated Seat Switch Conti-
nuity chart. If OK, refer to Step 6. If not OK, replace
the faulty heated seat switch.
HEATED SEAT SWITCH CONTINUITY
Switch PositionContinuity
BetweenResistance
Neutral 4 & 6 2.2 Kilohms
Low 4 & 6 .415 Kilohms
High 4 & 6 33 Ohms
(6) Replace the inoperative heated seat switch
with a known good unit and test the operation of the
switch indicator lamps. If OK, discard the faulty
heated seat switch. If not OK, (Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/
MEMORY HEATED SEAT/MIRROR MODULE -
DIAGNOSIS AND TESTING).
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Wait two minutes for the system reserve capac-
itor to discharge before beginning any airbag or
instrument panel service.
(3) Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL -
REMOVAL).
(4) Remove the screws that secure the heated seat
switch bezel to the instrument panel center bezel.
(5) Remove the heated seat switch bezel and both
switches from the instrument panel as a unit.
(6) From the back of the heated seat switch bezel,
gently pry the switch free and push the heated seat
switch out through the front of the bezel.
INSTALLATION
NOTE: When installing the heated seat switches, be
certain they are installed in the proper mounting
holes of the heated seat switch bezel. The heated
seat switches are differentiated by the keyway in
the connector receptacle on the backs of the
switches and keyway on the switch housing (Fig.
4).
(1) From the back of the heated seat switch bezel,
gently push the heated seat switch in through the
front of the bezel.
(2) Position the heated seat switch bezel to the
instrument panel center bezel and install the retain-
ing screws.
(3) Install the center bezel on the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(4) Connect the battery negative cable.
(5) Verify vehicle and system operation.
HEATED SEAT MODULE
DESCRIPTION
The heated seat module is also known as the Seat
Heat Interface Module. The heated seat module (Fig.
5) is located under the drivers front seat cushion,
where it is secured to a mounting bracket. The
heated seat module has a single connector receptacle
that allows the module to be connected to all of the
required inputs and outputs through the seat wire
harness.
DRHEATED SEAT SYSTEM 8G - 13
HEATED SEAT SWITCH (Continued)
Page 486 of 2627

HORN
TABLE OF CONTENTS
page page
HORN SYSTEM
DESCRIPTION..........................1
OPERATION............................1
DIAGNOSIS AND TESTING - HORN SYSTEM . . . 1
HORN
DIAGNOSIS AND TESTING - HORN..........1REMOVAL.............................2
INSTALLATION..........................2
HORN SWITCH
DESCRIPTION..........................2
DIAGNOSIS AND TESTING - HORN SWITCH . . . 2
HORN SYSTEM
DESCRIPTION
The dual-note horn system features dual electro-
magnetic horn units. The horn system includes the
following major components:
²Horn- The two horns are located on the left
side of the engine compartment below the Integrated
Power Module (IPM).
²Horn Switch- The horn switch is molded into
the driver airbag trim cover.
OPERATION
The horn system operates on battery current
received through a fuse in the Integrated Power
Module (IPM). The horn system circuit is designed so
that the system will remain operational, regardless
of the ignition switch position.
DIAGNOSIS AND TESTING - HORN SYSTEM
The most reliable, efficient, and accurate
means to diagnose the horn system requires the
use of a DRBIIItscan tool and the proper Diag-
nostic Procedures manual.
Refer to the appropriate wiring information.
In most cases, any problem involving continually
sounding horns can be quickly alleviated by removing
the horn fuse from the Integrated Power Module
(IPM).
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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.
HORN
DIAGNOSIS AND TESTING - HORN
The most reliable, efficient, and accurate
means to diagnose the horn system requires the
use of a DRBIIItscan tool and the proper Diag-
nostic Procedures manual. The DRBIIItscan
tool can provide confirmation that the PCI data
bus is functional, that all of the electronic mod-
ules are sending and receiving the proper mes-
sages on the PCI data bus, and that the horns
are being sent the proper hard wired outputs
for them to perform their functions.
Refer to the appropriate wiring information. The
wiring information 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 connectors, splices and grounds.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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.
DRHORN 8H - 1
Page 487 of 2627

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Disconnect the wire harness connectors from
the horns (Fig. 1).
(3) Remove mounting bolt and remove horns.
INSTALLATION
(1) Position horns and install mounting bolt.
Tighten the bolt to 10 N´m (85 in. lbs.).
(2) Connect wire harness connectors.
(3) Connect battery negative cable.
HORN SWITCH
DESCRIPTION
The horn switch is molded into the driver airbag.
The horn switch can not be serviced separately. For
service procedures, (Refer to 8 - ELECTRICAL/RE-
STRAINTS/DRIVER AIRBAG - REMOVAL).
DIAGNOSIS AND TESTING - HORN SWITCH
The most reliable, efficient, and accurate
means to diagnose the horn system requires the
use of a DRBIIItscan tool and the proper Diag-
nostic Procedures manual.
For complete circuit diagrams, refer to the appro-
priate wiring information.
WARNING: DISABLE THE AIRBAG SYSTEM
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, SEAT BELT TENSIONER, SIDE
AIRBAG, 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.
Fig. 1 HORN
1 - WIRE HARNESS CONNECTORS
2 - HORNS
3 - MOUNTING BOLT
8H - 2 HORNDR
HORN (Continued)
Page 488 of 2627

IGNITION CONTROL
TABLE OF CONTENTS
page page
IGNITION CONTROL
DESCRIPTION..........................1
SPECIFICATIONS
SPECIFICATIONS - TORQUE - IGNITION....3
ENGINE FIRING ORDER - 3.7L V-6.........4
ENGINE FIRING ORDER ± 4.7L V-8........4
FIRING ORDER / CABLE ROUTING ± 5.7L
V-8 ENGINE...........................4
SPARK PLUG CABLE RESISTANCE........4
SPARK PLUGS........................4
IGNITION COIL RESISTANCE - 3.7L V-6.....5
IGNITION COIL RESISTANCE - 4.7L V-8.....5
IGNITION COIL RESISTANCE - 5.7L V-8.....5
IGNITION TIMING......................5
AUTOMATIC SHUT DOWN RELAY
DESCRIPTION - PCM OUTPUT.............5
OPERATION
OPERATION - PCM OUTPUT.............5
OPERATION - ASD SENSE - PCM INPUT....5
DIAGNOSIS AND TESTING - ASD AND FUEL
PUMP RELAYS........................5
REMOVAL.............................6
INSTALLATION..........................6
CAMSHAFT POSITION SENSOR
DESCRIPTION..........................7
OPERATION............................7
REMOVAL.............................9
INSTALLATION.........................10IGNITION COIL
DESCRIPTION.........................11
OPERATION...........................12
REMOVAL.............................13
INSTALLATION.........................14
KNOCK SENSOR
DESCRIPTION.........................14
OPERATION...........................14
REMOVAL.............................15
INSTALLATION.........................15
SPARK PLUG
DESCRIPTION.........................17
DIAGNOSIS AND TESTING - SPARK PLUG
CONDITIONS.........................17
REMOVAL.............................19
CLEANING
CLEANING AND ADJUSTMENT...........20
INSTALLATION.........................20
IGNITION COIL CAPACITOR
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................21
INSTALLATION.........................21
SPARK PLUG CABLE
DESCRIPTION.........................21
OPERATION...........................21
REMOVAL.............................22
INSTALLATION.........................22
IGNITION CONTROL
DESCRIPTION
The ignition system is controlled by the Powertrain
Control Module (PCM) on all engines.
3.7L V-6 ENGINE
The 3.7L V-6 engine uses a separate ignition coil
for each cylinder. The one-piece coil bolts directly to
the cylinder head. Rubber boots seal the secondary
terminal ends of the coils to the top of all 6 spark
plugs. A separate electrical connector is used for each
coil.
Because of coil design, spark plug cables (second-
ary cables) are not used. A distributor is not used
with the 3.7L engine.
Two knock sensors (one for each cylinder bank) are
used to help control spark knock.The Auto Shutdown (ASD) relay provides battery
voltage to each ignition coil.
The ignition system consists of:
²6 Spark Plugs
²6 Separate Ignition Coils
²2 Knock Sensors
²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position, 2 knock and
MAP Sensors
4.7L V-8 ENGINE
The 4.7L V-8 engine uses a separate ignition coil
for each cylinder. The one-piece coil bolts directly to
the cylinder head. Rubber boots seal the secondary
terminal ends of the coils to the top of all 8 spark
plugs. A separate electrical connector is used for each
coil.
DRIGNITION CONTROL 8I - 1
Page 489 of 2627

Because of coil design, spark plug cables (second-
ary cables) are not used. A distributor is not used
with the 4.7L engine.
Two knock sensors (one for each cylinder bank) are
used to help control spark knock.
The Auto Shutdown (ASD) relay provides battery
voltage to each ignition coil.
The ignition system consists of:
²8 Spark Plugs
²8 Separate Ignition Coils
²2 Knock Sensors
²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position, 2 knock and
MAP Sensors
5.7L V-8 ENGINE
For additional information, also refer to Igni-
tion Coil Description and Operation.
The 5.7L V-8 engine is equipped with 16 spark
plugs. Two plugs are used for each cylinder. The 5.7L
is also equipped with 8 separate and independent
ignition coils. The one-piece coil bolts directly to the
cylinder head cover and attaches the coils secondary
output terminal directly to a spark plug using a rub-
ber boot seal. Each coil is also equipped with a sec-
ond output terminal. This second terminal connects a
conventional spark plug cable directly to a spark
plug on the opposite cylinder bank. A separate pri-
mary electrical connector is used for each coil.
Eight conventional spark plug cables are used with
the 5.7L. These cables connect a coil on one cylinder
bank, directly to a spark plug on the opposite cylin-
der bank. The cables are placed and routed in a spe-
cial plastic loom to keep them separated. This loom is
clipped to the intake manifold. To prevent a miss-
match of cables, a corresponding spark plug / coil
number is displayed on each plug cable: 1/6, 2/3, 4/7
and 5/8. These numbers can also be found on the top
of the intake manifold to the right of the throttle
body (Fig. 1).Two knock sensors (one for each cylinder bank) are
used to help control spark knock.
The 5.7L engine will not use a conventional distrib-
utor.
The ignition system consists of:
²16 Spark Plugs (2 per cylinder)
²8 Separate, Dual-Secondary Output, Ignition
Coils
²2 Knock Sensors
²8 Secondary Ignition Cables
²Powertrain Control Module (PCM)
²Also to be considered part of the ignition system
are certain inputs from the Crankshaft Position,
Camshaft Position, Throttle Position, 2 knock and
MAP Sensors
Fig. 1 FIRING ORDER / CABLE ROUTING - 5.7L V-8
ENGINE
1 - TOP OF INTAKE MANIFOLD
2 - CYLINDER FIRING ORDER (IGNITION COIL NUMBER)
3 - CORRESPONDING SPARK PLUG NUMBER
8I - 2 IGNITION CONTROLDR
IGNITION CONTROL (Continued)
Page 491 of 2627

ENGINE FIRING ORDER - 3.7L V-6
1-6-5-4-3-2
ENGINE FIRING ORDER ± 4.7L V-8
FIRING ORDER / CABLE ROUTING ± 5.7L V-8
ENGINE
Eight conventional spark plug cables are used with
the 5.7L. These cables connect a coil on one cylinder
bank, directly to a spark plug on the opposite cylin-
der bank. The cables are placed and routed in a spe-
cial plastic loom to keep them separated. This loom is
clipped to the intake manifold. To prevent a miss-match of cables, a corresponding spark plug / coil
number is displayed on each plug cable: 1/6, 2/3, 4/7
and 5/8. These numbers can also be found on the top
of the intake manifold to the right of the throttle
body (Fig. 2).
SPARK PLUG CABLE RESISTANCE
MINIMUM MAXIMUM
250 Ohms Per Inch 1000 Ohms Per Inch
3000 Ohms Per Foot 12,000 Ohms Per Foot
SPARK PLUGS
ENGINE PLUG TYPE ELECTRODE GAP
3.7L V-6 ZFR6F - 11G (NGK) 1.1 (0.042 in.)
4.7L V-8 RC12MCC4 1.01 mm (.040 in.)
5.7L V-8 Champion - RE14MCC4 1.14 mm (.045 in.)
Fig. 2 FIRING ORDER / CABLE ROUTING - 5.7L V-8
ENGINE
1 - TOP OF INTAKE MANIFOLD
2 - CYLINDER FIRING ORDER (IGNITION COIL NUMBER)
3 - CORRESPONDING SPARK PLUG NUMBER
8I - 4 IGNITION CONTROLDR
IGNITION CONTROL (Continued)
Page 499 of 2627

OPERATION
3.7L V-6
Battery voltage is supplied to the 6 individual igni-
tion coils from the ASD relay. The Powertrain Con-
trol Module (PCM) opens and closes each ignition coil
ground circuit at a determined time for ignition coil
operation.
Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used with the 3.7L V-6 engine.
4.7L V-8
Battery voltage is supplied to the 8 individual igni-
tion coils from the ASD relay. The Powertrain Con-
trol Module (PCM) opens and closes each ignition coil
ground circuit at a determined time for ignition coil
operation.
Fig. 17 IGNITION COIL LOCATION - 4.7L V-8
1 - IGNITION COIL
2 - COIL ELECTRICAL CONNECTOR
3 - COIL MOUNTING STUD/NUT
Fig. 18 IGNITION COIL - 5.7L V-8
1 - IGNITION COIL
2 - MOUNTING BOLTS (2)
3 - BOOT TO SPARK PLUG
Fig. 19 IGNITION COIL R/I Ð 5.7L V-8
1 - SLIDE LOCK (SLIDE OUTWARD TO UNLOCK)
2 - SPARK PLUG CABLE (TO OPPOSITE CYLINDER BANK
SPARK PLUG)
3 - RELEASE LOCK / TAB (PUSH HERE)
4 - ELEC. CONNECTOR
5 - IGNITION COIL
6 - COIL MOUNTING BOLTS (2)
7 - SPARK PLUG CABLE (TO OPPOSITE CYLINDER BANK
IGNITION COIL)
8I - 12 IGNITION CONTROLDR
IGNITION COIL (Continued)
Page 500 of 2627

Base ignition timing is not adjustable.By con-
trolling the coil ground circuit, the PCM is able to set
the base timing and adjust the ignition timing
advance. This is done to meet changing engine oper-
ating conditions.
The ignition coil is not oil filled. The windings are
embedded in an epoxy compound. This provides heat
and vibration resistance that allows the ignition coil
to be mounted on the engine.
Because of coil design, spark plug cables (second-
ary cables) are not used with the 4.7L V-8 engine.
5.7L V-8
The ignition system is controlled by the Powertrain
Control Module (PCM) on all engines.
A ªwasted sparkº system is used on the 5.7L
engine combining paired, or dual-firing coils, and 2
spark plugs per cylinder. The coils and spark plugs
are connected with paired, secondary high-voltage
cables.
Each cylinder is equipped with 1 dual-output coil.
Meaning one coil mounts directly over one of the
dual spark plugs for 1 high-voltage output. A second
high-voltage output is supplied directly from the
same coil (using a plug cable) to one of the dual
spark plugs on a corresponding (paired) cylinder on
the opposite cylinder bank.
Each coil fires 2 spark plugs simultaneously on
each of the cylinder banks (one cylinder on compres-
sion stroke and one cylinder on exhaust stroke).
EXAMPLE :When the #1 cylinder is on compression
stroke and ready for spark, the #1 coil will fire one of
the dual spark plugs on the #1 cylinder (directly
below the coil). The other dual spark plug on the #1
cylinder will be fired by the #6 coil. At the same
time, the #1 coil will fire a ªwasted sparkº to one of
the dual spark plugs at the #6 cylinder as coil #6 also
fires a ªwasted sparkº to one of the dual spark plugs
at the #6 cylinder.
The firing order is paired at cylinders 1/6, 2/3, 4/7,
5/8. Basic cylinder firing order is 1±8±4±3±6±5±7±2.
Battery voltage is supplied to all of the ignition
coils positive terminals from the ASD relay. If the
PCM does not see a signal from the crankshaft and
camshaft sensors (indicating the ignition key is ON
but the engine is not running), it will shut down the
ASD circuit.
Base ignition timing is not adjustable on the
5.7L V-8 engine.By controlling the coil ground cir-
cuits, the PCM is able to set the base timing and
adjust the ignition timing advance. This is done to
meet changing engine operating conditions.
The PCM adjusts ignition timing based on inputs it
receives from:
²The engine coolant temperature sensor
²The crankshaft position sensor (engine speed)²The camshaft position sensor (crankshaft posi-
tion)
²The manifold absolute pressure (MAP) sensor
²The throttle position sensor
²Transmission gear selection
REMOVAL
3.7L V-6
An individual ignition coil is used for each spark
plug (Fig. 15). The coil fits into machined holes in the
cylinder head. A mounting stud/nut secures each coil
to the top of the intake manifold (Fig. 16). The bot-
tom of the coil is equipped with a rubber boot to seal
the spark plug to the coil. Inside each rubber boot is
a spring. The spring is used for a mechanical contact
between the coil and the top of the spark plug. These
rubber boots and springs are a permanent part of the
coil and are not serviced separately. An o-ring (Fig.
15) is used to seal the coil at the opening into the cyl-
inder head.
(1) Depending on which coil is being removed, the
throttle body air intake tube or intake box may need
to be removed to gain access to coil.
(2) Disconnect electrical connector from coil by
pushing downward on release lock on top of connec-
tor and pull connector from coil.
(3) Clean area at base of coil with compressed air
before removal.
(4) Remove coil mounting nut from mounting stud
(Fig. 16).
(5) Carefully pull up coil from cylinder head open-
ing with a slight twisting action.
(6) Remove coil from vehicle.
4.7L V-8
An individual ignition coil is used for each spark
plug (Fig. 15). The coil fits into machined holes in the
cylinder head. A mounting stud/nut secures each coil
to the top of the intake manifold (Fig. 17). The bot-
tom of the coil is equipped with a rubber boot to seal
the spark plug to the coil. Inside each rubber boot is
a spring. The spring is used for a mechanical contact
between the coil and the top of the spark plug. These
rubber boots and springs are a permanent part of the
coil and are not serviced separately. An o-ring (Fig.
15) is used to seal the coil at the opening into the cyl-
inder head.
(1) Depending on which coil is being removed, the
throttle body air intake tube or intake box may need
to be removed to gain access to coil.
(2) Disconnect electrical connector (Fig. 17) from
coil by pushing downward on release lock on top of
connector and pull connector from coil.
(3) Clean area at base of coil with compressed air
before removal.
DRIGNITION CONTROL 8I - 13
IGNITION COIL (Continued)
Page 501 of 2627

(4) Remove coil mounting nut from mounting stud
(Fig. 17).
(5) Carefully pull up coil from cylinder head open-
ing with a slight twisting action.
(6) Remove coil from vehicle.
5.7L V-8
Before removing or disconnecting any spark plug
cables, note their original position. Remove cables
one-at-a-time. To prevent ignition crossfire, spark
plug cablesMUSTbe placed in cable tray (routing
loom) into their original position.
An individual ignition coil (Fig. 18) is used at each
cylinder. The coil mounts to the top of the valve cover
with 2 bolts (Fig. 19). The bottom of the coil is
equipped with a rubber boot to seal the spark plug to
the coil. Inside each rubber boot is a spring. The
spring is used for a mechanical contact between the
coil and the top of the spark plug.
(1) Depending on which coil is being removed, the
throttle body air intake tube or intake box may need
to be removed to gain access to coil.
(2) Unlock electrical connector (Fig. 19) by moving
slide lock first. Press on release lock (Fig. 19) while
pulling electrical connector from coil.
(3) Disconnect secondary high-voltage cable from
coil with a twisting action.
(4) Clean area at base of coil with compressed air
before removal.
(5) Remove 2 mounting bolts (note that mounting
bolts are retained to coil).
(6) Carefully pull up coil from cylinder head open-
ing with a slight twisting action.
(7) Remove coil from vehicle.
(8) Before installing spark plug cables to either the
spark plugs or coils, or before installing a coil to a
spark plug, apply dielectric grease to inside of boots.
INSTALLATION
3.7L V-6
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Check condition of coil o-ring and replace as
necessary. To aid in coil installation, apply silicone to
coil o-ring.
(3) Position ignition coil into cylinder head opening
and push onto spark plug. Do this while guiding coil
base over mounting stud.
(4) Install coil mounting stud nut. Refer to torque
specifications.
(5) Connect electrical connector to coil by snapping
into position.
(6) If necessary, install throttle body air tube.
4.7L V-8
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Check condition of coil o-ring and replace as
necessary. To aid in coil installation, apply silicone to
coil o-ring.
(3) Position ignition coil into cylinder head opening
and push onto spark plug. Do this while guiding coil
base over mounting stud.
(4) Install coil mounting stud nut. Refer to torque
specifications.
(5) Connect electrical connector to coil by snapping
into position.
(6) If necessary, install throttle body air tube.
5.7L V-8
(1) Using compressed air, blow out any dirt or con-
taminants from around top of spark plug.
(2) Before installing spark plug cables to either the
spark plugs or coils, or before installing a coil to a
spark plug, apply dielectric grease to inside of boots.
(3) Position ignition coil into cylinder head opening
and push onto spark plug. Twist coil into position.
(4) Install 2 coil mounting bolts. Refer to torque
specifications.
(5) Connect electrical connector to coil by snapping
into position.
(6) Install cable to coil. To prevent ignition cross-
fire, spark plug cablesMUSTbe placed in cable tray
(routing loom) into their original position. Refer to
Spark Plug Cable Removal for a graphic.
(7) If necessary, install throttle body air tube.
KNOCK SENSOR
DESCRIPTION
The sensors are used only with 3.7L V-6, 4.7L V-8
and 5.7L V-8 engines. On 3.7L V-6 and 4.7L V-8
engines, the 2 knock sensors are bolted into the cyl-
inder block under the intake manifold.
On 5.7L V-8 engines, 2 knock sensors are also
used. These are bolted into each side of the cylinder
block (outside) under the exhaust manifold.
OPERATION
3.7L V-6 / 4.7L V-8 / 5.7L V-8 Engines Only
Two knock sensors are used; one for each cylinder
bank. When the knock sensor detects a knock in one
of the cylinders on the corresponding bank, it sends
an input signal to the Powertrain Control Module
(PCM). In response, the PCM retards ignition timing
for all cylinders by a scheduled amount.
8I - 14 IGNITION CONTROLDR
IGNITION COIL (Continued)