
8A
- 18
ELECTRICAL
• BATTERY SPECIFICATIONS
Load
Test
(Amps)
Cold
Cranking
Rating @ 0°F Reserve
Capacity
300 Amp 600 Amp 120 Minutes
405 Amp 810 Amp 133 Minutes
535 Amp 1075 Amp 170 Minutes
CRANKING
RATING
is the
current
a
battery
can deliver for 30
seconds
and maintain a
terminal
voltage of 7.2 volts or greater at specified
temperature.
RESERVE
CAPACITY RATING
is the length of
time
a
battery
can deliver 25 amps and maintain a minimum
terminal
voltage of 10.5 volts
at27°C
(80 °F).
J938A-25 GAS ENGINE STARTER
DIESEL ENGINE STARTER
Manufacturer
Nippondenso
Engine
Application 5.9L, 5.21 e\ 3.9L
Part Number and
53005984
Power Rating 1.4 Kw
Voltage 12
No.
of Fields 4
No.
of
Poles.
4
Brushes
4
Drive Reduction
Gear Train
Free
Running Test Voltage 11
Amperage Draw ............ 73
Amps
Minimum Speed rpm 3601 rpm
Solenoid
Closing
Voltage 7.5 Volts
Cranking Amperage Draw Test . . .
125-200
Amps*
*
Engine
should
be up to operating
temperature.
Extremely heavy oil or tight engine
will
increase
starter
amperage draw.
J938B-14
REDUCTION
GEAR
STARTER
Manufacturer
Nippondenso
Engine
Application 5.9L
Part Number and Power Rating ..............
4428221
3
kw
Voltage 12
No.
of Fields 4
No.
of
Poles
4
Brushes
.................... 4
Drive Conventional
Gear Train
Free
Running Test Voltage .
Amperage Draw
Minimum Speed rpm 11
220
Amps
Max.
4200
rpm Min.
Solenoid
Closing
Voltage. 8 Volts
Cranking Amperage Draw Test . .
450-550
Amps*
*
Engine
should be up to operating heavy oil or tight engine
will
increase
temperature.
Extremely
starter
amperage draw. J918B-21
SPECIFICATIONS

•
BATTERY/STARTER/GENERATOR
SERVICE
8B - 9
Load
Test
(Amps)
cold
Cranking
Rating
@ 0°F
Reserve
Capacity
300 Amp 600 Amp 120 Minutes
405 Amp 810 Amp 133 Minutes
535 Amp 1075 Amp
170 Minutes
CRANKING
RATING
is the
current
a
battery
can
deliver
for 30
seconds
anej
maintain
a
terminal
voltage
of 7.2
volts
or
greater
at
specified
temperature.
RESERVE
CAPACITY RATING
is the
length
of
time
a
battery
can
deliver
25
amps and maintain
a
minimum
terminal
voltage
of
10.5 volts
at
27 °C (80
°F).
J938A-25
GAS ENGINE DIESEL ENGINE
Manufacturer
Nippondenso
Engine
Application 5.9L, 5.2L
&
3.9L
Part Number and
53005984
Power Rating
1.4
Kw
Voltage
12
No.
of
Fields 4
No.
of
Poles. 4
Brushes
4
Drive Reduction
Gear
Train
Free
Running Test Voltage 11
Amperage Draw 73 Amps
Minimum Speed
rpm
3601
rpm
Solenoid
Closing Voltage 7.5 Volts
Cranking Amperage Draw Test
. . .
125-200
Amps*
*
Engine
should be up to operating
temperature.
Extremely heavy oil
or
tight engine
will
increase
starter
amperage draw.
J938B-14
REDUCTION
GEAR
STARTER
Manufacturer
Nippondenso
Engine
Application 5.9L
Part Number
and
Power Rating
4428221
3
kw
Voltage
12
No.
of
Fields
4
No.
of
Poles 4
Brushes
4
Drive Conventional
Gear Train
Free
Running Test Voltage
Amperage Draw
Minimum Speed
rpm
11
220 Amps Max.
4200
rpm Min.
Solenoid
Closing Voltage 8 Volts
Cranking Amperage Draw Test
. .
450-550
Amps*
*
Engine
should
be up to
operating
temperature.
Extremely heavy oil or tight engine
will
increase
starter
amperage draw.
J918B-21
GENERATOR SPECIFICATIONS
TYPE
PHUT
HUMSIR
PULLEY
GROOVES
ENGINE
RATING
NIPPONDENSO
53008646
7
ALL GASOLINE 75 AMPS
NIPPONDENSO
53008647
7
ALL GASOLINE 90 AMPS
NIPPONDENSO
53008651
7
ALL GASOLINE
120
AMPS
NIPPONDENSO
5234374
8
DIESEL
120 AMPS
J938B-28
SPECIFICATIONS
BATTERY SPECIFICATIONS

•
IGNITION
SYSTEMS
8D
- 1
CONTENTS
page page
COMPONENT IDENTIFICATION/SYSTEM DIAGNOSTICS/SERVICE PROCEDURES
7
OPERATION
1
IGNITION SWITCH
25
COMPONENT REMOVAL/INSTALLATION
..... 18
SPECIFICATIONS
28
COMPONENT
IDENTIFICATION/SYSTEM OPERATION
INDEX
page
Automatic
Shut Down (ASD) Relay
1
Camshaft Position Sensor
2
Crankshaft Position Sensor
2
Distributors
3
Engine Coolant
Temperature
Sensor
...........
4
General
Information
1
page
Ignition
Coil
3
Intake
Manifold Charge
Air
Temperature
Sensor
. . 4
Manifold Absolute Pressure (MAP) Sensor
4
Powertrain
Control
Module (PCM)
. 5
Throttle
Position Sensor
5
GENERAL
INFORMATION
Throughout this group, references
are
made
to
par
ticular vehicle models
by
alphabetical designation
or
by
the
particular vehicle nameplate.
A
chart showing a breakdown
of
alphabetical designations
is
included
in
the
Introduction group
at the
beginning
of
this
manual. 5.9L
gas
powered engines will
be
referred
to as ei
ther: LDC (Light Duty Cycle),
or
HDC (Heavy Duty Cycle). This section
of the
group, Component Identifica
tion/System Operation, will discuss ignition system operation
and
will identify ignition system compo
nents.
For diagnostic procedures
and
adjustments, refer
to
the Diagnostics/Service Procedures section
of
this
group.
For removal
and
installation
of
ignition system
components, refer
to the
Component Removal/Instal
lation section
of
this group. For other useful information, refer
to
On-Board
Di
agnostics
in the
General Diagnosis sections
of
Group
14,
Fuel System
in
this manual. For operation
of the DRB II
Diagnostic Scan Tool,
refer
to the
appropriate Powertrain Diagnostic Proce
dures service manual.
An Ignition specifications section
is
included
at the
end
of
this group.
A
general Maintenance Schedule (mileage intervals)
for
ignition related items
can be
found
in
Group
0,
Lubrication and Maintenance. This
schedule
can
also
be
found
in the
Owners Manual.
IGNITION
SYSTEMS
The ignition systems used
on all
engines
are
basi
cally identical. Similarities
and
differences between
the systems will
be
discussed.
A sequential multi-port fuel injection system
is
used
on all gas
powered engines.
The ignition system
is
controlled
by the
powertrain
control module (PCM)
on all
engines.
The
PCM
was
formerly referred
to as the
SBEC
or
engine control ler.
The ignition system consists
of:
• Spark Plugs
• Ignition Coil
• Secondary Ignition Cables
• Ignition distributor. Contains rotor
and
camshaft
position sensor • Powertrain Control Module (PCM)
• Crankshaft Position Sensor
AUTOMATIC SHUT DOWN (ASD) RELAY
The automatic shut down (ASD) relay
is
located
in
the engine compartment (Fig.
1). As one of its
func
tions,
the ASD
relay will supply battery voltage
to
the ignition coil.
The
ground circuit
for the
ASD
re
lay
is
controlled
by the
powertrain control module (PCM).
The PCM
regulates
ASD
relay operation
by
switching
the
ground circuit on-and-off.
IGNITION
SYSTEMS

•
IGNITION
SYSTEMS
8D - 3 For removal and installation of this sensor, refer to
the Component Removal/Installation section of this
group.
CRANKSHAFT
POSITION
SENSOR
NOTCHES- FLYWHEEL CRANKSHAFT
POSITION-
SENSOR
NOTCHES* .FLYWHEEL
J9314-88
—^^j^jV^
J9314-89
Fig.
4
Sensor
Operation—3.9L
Engine
SENSOR
OPERATION'-5.2U5.9L
ENGINES On 5.2L and 5.9L engines, the flywheel/drive plate
has 8 single notches, spaced every 45 degrees, at its outer edge (Fig. 5).
The notches cause a pulse to be generated when
they pass under the sensor. The pulses are the input to the PCM. For each engine revolution, there are 8
pulses generated on V-8 engines.
The engine will not operate if the PCM does not re
ceive a crankshaft position sensor input. For component testing, refer to the Diagnostics/Ser
vice Procedures section of this group.
For removal and installation of this component, re
fer to the Component Removal/Installation section of
this group.
DISTRIBUTORS
For component testing, refer to the Diagnostics/Ser
vice Procedures section of this group.
ALL
ENGINES All engines are equipped with a camshaft driven
mechanical distributor, containing a shaft driven dis
tributor rotor. They are equipped with an internal camshaft position (fuel sync) sensor. This sensor pro
vides fuel injection synchronization and cylinder identification.
Distributors do not have built in centrifugal or vac
uum assisted advance. Base ignition timing and all
timing advance is controlled by the powertrain con
trol module (PCM). Because ignition timing is con-
Fig.
5
Sensor
Opera tion—5.2L/5.9L
Engine
trolled by the PCM, base ignition timing is not adjustable on any of these engines.
The distributor is held to the engine in the conven
tional method using a holddown clamp and bolt. Al
though the distributor can be rotated, it will
have no effect on ignition timing.
All distributors contain an internal oil seal that
prevents oil from entering the distributor housing.
The seal is not serviceable.
For removal and installation of this component, re
fer to the Component Removal/Installation section of
this group.
IGNITION
COIL
Battery voltage is supplied to the ignition coil pos
itive terminal from the ASD relay. The powertrain control module (PCM) opens and
closes the ignition coil ground circuit for ignition coil operation. Base ignition timing is not adjustable on any
engine. By controlling the coil ground circuit, the
PCM is able to set the base timing and adjust the ig nition timing advance. This is done to meet changing engine operating 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. • 3.9L/5.2L/5.9L LDC-Gas Engines: The coil is
mounted to a bracket that is bolted to the front of the right engine cylinder head (Fig. 6). This bracket is also used to mount the automatic belt tensioner.

8D
- 4
IGNITION
SYSTEMS
•
Fig. 6 ignition Coil—3.9L/5.2L/5.9L
LDC-Gas
Engines Fig. 7 Ignition Coil—5.9L
HDC-Gas
Engine
• 5.9L HDC-Gas Engines: The coil is mounted to a
bracket that is bolted to the automatic belt tensioner mounting bracket (Fig. 7).
For component testing, refer to the Diagnostics/Ser
vice Procedures section of this group.
For removal and installation of this component, re
fer to the Component Removal/Installation section of
this group.
ENGINE COOLANT TEMPERATURE
SENSOR
The sensor provides an input voltage to the power-
train control module (PCM) relating coolant temper ature. The PCM uses this input, along with inputs
from other sensors, to determine injector pulse width and ignition timing. As coolant temperature varies,
the coolant temperature sensor resistance will
change, resulting in a different input voltage to the
PCM. When the engine is cold, the PCM will operate in
the Open Loop Cycle. It will demand slightly richer air-fuel mixtures and higher idle speeds, until nor mal operating temperatures are reached. Refer to
Modes Of Operation in Group 14, Fuel System for a
description of Open and Closed Loop operation.
The sensor is installed in the intake manifold near
the thermostat housing (Fig. 8).
Fig. 8 Coolant Temperature Sensor—Typical
For component testing, refer to the Diagnostics/Ser
vice Procedures section of this group. For removal and installation of this component, re
fer to the Component Removal/Installation section of
this group.
INTAKE MANIFOLD CHARGE
AIR
TEMPERATURE
SENSOR
The sensor element extends into the intake mani
fold air stream. It provides an input voltage to the
powertrain control module (PCM) indicating intake
manifold air temperature. The input from this sensor is used along with inputs from other sensors to de
termine injector pulse width. As the temperature of
the air-fuel stream in the manifold varies, the sensor
resistance will change. This will result in a different input voltage to the PCM. For more information, re
fer to Group 14, Fuel System. This sensor is installed in the intake manifold
(Figs.
9 or 10). For component testing, refer to the Diagnostics/Ser
vice Procedures section of this group. For removal and installation of this component, re
fer to the Component Removal/Installation section of
this group.
MANIFOLD ABSOLUTE
PRESSURE
(MAP)
SENSOR
The MAP sensor reacts to absolute pressure in the
intake manifold and provides an input voltage to the
powertrain control module (PCM). As engine load changes, manifold pressure varies, causing the MAP
sensor voltage to change. This change results in a
different input voltage to the PCM. The input volt age level supplies the PCM with information. This
relates to ambient barometric pressure during engine

•
IGNITION
SYSTEMS
8D - 5
THROTTLE
^
BODY
u
BRACKET
y^SUPPORT
BRACKET
/ |
CHARGE
AIR
ijmmmmk
TEMPERATURE
SENSOR
THROTTLE
BODY
Fig.
9
Sensor
Location—3.9L Engine—Typical
INTAKE MANIFOLD
'b AIR TEMPERATURE
SENSOR
J9314-162
Fig.
10
Sensor
Location—5.2L/5.9L
Engines—Typical
start-up (cranking) and to engine load while the en
gine is running. The PCM uses this input, along with
inputs from other sensors, to adjust air-fuel mixture.
For more information, refer to Group 14, Fuel Sys
tem.
The MAP sensor is mounted to the throttle body
(Fig. 11). It is connected to the throttle body with an
L-shaped rubber fitting and to the PCM electrically. For component testing, refer to the Diagnostics/Ser
vice Procedures section of this group. For removal and installation of this component, re
fer to the Component Removal/Installation section of
this group.
POWERTRAIN CONTROL MODULE
(PCM) The powertrain control module (PCM) is located in
the engine compartment behind the battery (Fig. 12).
The PCM was formerly referred to as the SBEC or engine controller. The ignition system is controlled by the PCM. Base ignition timing by rotation of distributor
is not adjustable.
MANIFOLD
ABSOLUTE
PRESSURE
SENSOR
TORQUE CONVERTER CLUTCH RELAY
ELECTRICAL
Jlp^
CONNECTOR
^gis!—
Fig.
11 MAP Sensor—Typical
A/C
CLUTCH RELAY STARTER RELAY
AUTO
SHUTDOWN RELAY FUEL PUMP RELAY
DATA LINK
CONNECTOR POWERTRAIN
CONTROL
MODULE
J9314-164
Fig.
12 PCM Location—Typical The PCM opens and closes the ignition coil ground
circuit to operate the ignition coil. This is done to ad
just ignition timing, both initial (base) and advance, for changing engine operating conditions.
The amount of electronic spark advance provided
by the PCM is determined by five input factors: Cool ant temperature, engine rpm, intake manifold tem
perature, manifold absolute pressure and throttle
position.
For removal and installation of this component, re
fer to the Component Removal/Installation section of
this group.
For diagnostics, refer to the appropriate Powertrain
Diagnostic Procedures service manual for operation
of the DRB II scan tool.
THROTTLE
POSITION
SENSOR
The sensor is mounted on the throttle body (Fig.
13).
It is connected to the throttle blade shaft. The
sensor is a variable resistor. It provides the power-
train control module (PCM) with an input signal (voltage) that represents throttle blade position. As

•
IGNITION
SYSTEMS
80 - 7
DIAGNOSTICS/SERW1CE
PROCEDURES
INDEX
page
Automatic Shut Down (ASD) Relay
7
Camshaft Position
Sensor
Test
...............
7
Crankshaft Position
Sensor
Test
8
Distributor
Cap
8
Distributor
Rotor
8
Engine
Coolant Temperature
Sensor
Test
10
General
Information
7
Ignition
Coil
8
Ignition
Secondary
Circuit
Diagnosis
10
GENERAL
INFORMATION
This section
of the
group, Diagnostics/Service Pro
cedures, will discuss basic ignition system diagnos
tics
and
service adjustments. For system operation
and
component identification,
refer
to the
Component Identification/System Opera
tion section
of
this group. For removal
or
installation
of
ignition system com
ponents, refer
to the
Component Removal/Installa
tion section
of
this group. For other useful information, refer
to
On-Board
Di
agnostics
in the
General Diagnosis sections
of
Group
14,
Fuel System
in
this manual. For operation
of the DRB II
Diagnostic Scan Tool,
refer
to the
appropriate Powertrain Diagnostic Proce
dures service manual.
AUTOMATIC SHUT DOWN
(ASD)
RELAY
Refer
to
Relays—Operation/Testing
in the
Group
14,
Fuel System section
of
this service manual.
CAMSHAFT POSITION SENSOR TEST
The camshaft position sensor
is
located
in the
dis
tributor
on all
engines. To perform
a
complete test
of
this sensor
and its
circuitry, refer
to the DRB II
diagnostic scan tool.
Also refer
to the
appropriate Powertrain Diagnostics
Procedures manual.
To
test
the
sensor only, refer
to
the following: For this test,
an
analog (non-digital) voltmeter
is needed.
Do not
remove
the
distributor connector from
the
distributor. Using small paper clips, insert
them into
the
backside
of the
distributor wire har ness connector
to
make contact with
the
terminals.
Be sure that
the
connector
is not
damaged when
in
serting
the
paper clips. Attach voltmeter leads
to
these paper clips. (1) Connect
the
positive (
+
)
voltmeter lead into
the sensor output wire. This
is at
done
the
distribu tor wire harness connector.
For
wire identification,
refer
to
Group
8W,
Wiring Diagrams.
page
Ignition
Timing
12
Intake Manifold Charge
Air
Temperature
Sensor
Test
12
Manifold Absolute Pressure (MAP)
Sensor
Test
. 12
Oxygen
Sensor
Tests
17
Powertrain Control Module (PCM)
............
14
Spark
Plug Secondary Cables
16
Spark
Plugs
............................
14
Throttle
Position
Sensor
Test
17
(2) Connect
the
negative
(-)
voltmeter lead into
the
ground wire.
For
wire identification, refer
to
Group
8W, Wiring Diagrams.
(3)
Set the
voltmeter
to the 15
Volt
DC
scale. (4) Remove distributor
cap
from distributor
(two
screws). Rotate (crank)
the
engine until
the
distribu
tor rotor
is
pointed towards
the
rear
of
vehicle.
The
movable pulse ring should
now be
within
the
sensor
pickup.
(5) Turn ignition
key to ON
position. Voltmeter
should read approximately
5.0
volts.
(6)
If
voltage
is not
present, check
the
voltmeter
leads
for a
good connection.
(7)
If
voltage
is
still
not
present, check
for
voltage
at
the
supply wire.
For
wire identification, refer
to
Group
8W,
Wiring Diagrams.
(8)
If
voltage
is not
present
at
supply wire, check
for voltage
at
pin-7
of
powertrain control module (PCM) 60-way connector. Leave
the PCM
connector
connected
for
this test. (9)
If
voltage
is
still
not
present, perform vehicle
test using
the DRB II
diagnostic scan tool. (10)
If
voltage
is
present
at
pin-7,
but not at the
supply wire: (a) Check continuity between
the
supply wire.
This
is
checked between
the
distributor connector and pin-7
at the PCM. If
continuity
is not
present,
repair
the
harness
as
necessary. (b) Check
for
continuity between
the
camshaft
position sensor output wire
and
pin-44
at the PCM.
If continuity
is not
present, repair
the
harness
as
necessary. (c) Check
for
continuity between
the
ground cir
cuit wire
at the
distributor connector
and
ground.
If continuity
is not
present, repair
the
harness
as
necessary. (11) While observing
the
voltmeter, crank
the en
gine with ignition switch.
The
voltmeter needle should fluctuate between
0 and 5
volts while
the en
gine
is
cranking. This verifies that
the
camshaft
po
sition sensor
in the
distributor
is
operating properly
and
a
sync pulse signal
is
being generated.

•
IGNITION
SYSTEMS
80 - 9
Fig.
4 Cap Inspection—internal—Typical
INSUFFICIENT
SPRING
TENSION
CORRODED
EVIDENCE
OF
PHYSICAL
CONTACT
WITH
CAP
J908D-48
Fig.
5 Rotor Inspection—Typical
Also refer to the appropriate Powertrain Diagnostics
Procedures manual. To test the coil only, refer to the
following:
The ignition coil (Figs. 6 or 7) is designed to oper
ate without an external ballast resistor.
Fig.
6 Ignition Coil-3.9U5.2U5.9L
LDC-Gas
Engine
Fig.
7 Ignition Coil—5.9L
HDC-Gas
Engine
Inspect the ignition coil for arcing. Test the coil ac
cording to coil tester manufacturer's instructions.
Test the coil primary and secondary resistance. Re
place any coil that does not meet specifications. Refer
to the Ignition Coil Resistance chart.
If the ignition coil is being replaced, the secondary
spark plug cable must also be checked. Replace cable
if it has been burned or damaged.
IGNITION
COIL RESISTANCE
PRIMARY RESISTANCE SECONDARY RESISTANCE
COIL
(MANUFACTURER)
2!-27°C (70-80°F)
21-27°C
(70-80°F)
Diamond
0.97 - 1.18
Ohms
11,300-
15,300
Ohms
Toyodenso
0.95- 1.20
Ohms
11,300-
13,300
Ohms
J918D-2