1993 DODGE TRUCK sensor

14 - 80
FUEL SYSTEM

•
SCI
RECEIVE-PCM
INPUT

The serial communication interface (SCI) receive
and transmit outputs allow the PCM to communicate
with the DRB II scan tool.

SENSOR
RETURN-PCM
INPUT
Sensor return provides a low noise ground refer­
ence for all system sensors.

SIGNAL
GROUND-PCM
INPUT
Provides a common ground for the input signals.

SPEED
CONTROL-PCM
INPUT
The PCM regulates the speed control system based
on inputs it receives. The speed control operating
range is from 35 to 85 mph. Inputs that effect speed control operation are:
• Park/neutral switch
• Vehicle speed sensor
• Throttle position sensor
• Engine speed sensor
• Brake switch

THROTTLE
POSITION SENSOR (TPS) —PCM
INPUT
The throttle position sensor is not used with man­
ual transmissions. The throttle position sensor (TPS) is mounted on
the top of the fuel injection pump (Fig. 9). The TPS
provides an input to the PCM. It senses how far the
throttle is open (past the idle position). The PCM uses the TPS input, along with vehicle speed sensor and engine speed sensor inputs to determine 3-4 up­
shift (overdrive) and 4-3 downshift. The TPS is a potentiometer. The PCM supplies 5
volts to the sensor. TPS output to the PCM varies
from approximately 1.0 volt at idle to 3.5 volts at
wide open throttle (WOT). T

J9114-237

Fig.
9
Throttle
Position
Sensor
VEHICLE SPEED SENSOR-PCM
INPUT
The vehicle speed sensor (Fig. 10) is located in the
extension housing of the transmission (2WD) or on the transfer case extension housing (4WD). A signal
is sent from this sensor, along with signals from both
the TPS and the engine speed sensor, to the PCM.
The PCM will then use this information to determine
when to shift into and out of overdrive.
The speed sensor is also used in determining speed
control set, decelerate, accelerate, maximum set
speed (85 mph) and minimum set speed (35 mph) op­
erations.
VEHICLE

SPEED

SENSOR

Fig.
10 Vehicle
Speed
Sensor—Typical Location

WATER-IN-FUEL SENSOR-PCM
INPUT
The water-in-fuel (WIF) sensor is located at the
bottom of the fuel/water separator filter (Fig. 11). The sensor sends an input to the PCM when it senses
water in the fuel. The PCM looks at the water-in-fuel sensor signal when the ignition key is put in the ON
position. It also monitors the input at the end of the intake heater post-heat cycle. The PCM turns the water-in-fuel indicator lamp to
the ON position if water is detected in the fuel. The
water-in-fuel indicator lamp is located in the instru­ ment panel.
J91 14-85

Fig.
11 Water-in-Fuel
Sensor

•

FUEL
SYSTEM
14-81
AIR
CONDITIONING
(A/C)
CLUTCH RELAY—PCM
OUTPUT
The PCM activates the A/C compressor through the
A/C clutch relay. The PCM regulates A/C compressor
operation by switching the ground circuit for the A/C
clutch relay on and off. The relay is located in the engine compartment (Fig. 3). By switching the ground path for the relay on and
off, the PCM is able to cycle the A/C compressor
clutch. This is based on changes in engine operating
conditions. If, during A/C operation, the PCM senses
a low idle speed, it will de-energize the relay. This
prevents A/C clutch engagement. The relay will re­ main de-energized until the idle speed increases.

GENERATOR
FIELD-PCM
OUTPUT
The PCM regulates the charging system voltage
within a range of 12.9 to 15.0 volts. It will control
ASD relay operation. The input (through the PCM)
for the ASD relay comes from the engine speed sen­ sor. When engine running speed is above 384 rpm, a
signal is sent from the PCM to engage the ASD re­
lay. This supplies the necessary generator field wind­
ing control. When rpm drops below 320, the signal to
the ASD relay is stopped. Refer to Group 8A, for charging system information.

AIR INTAKE HEATER RELAYS-PCM
OUTPUT
The PCM operates the air intake heaters through
the air intake heater relays (Fig. 12). The relays may
be energized before and after cranking, depending upon intake manifold air temperature. The PCM
monitors intake manifold air temperature through
the charge air temperature sensor. Refer to Air In­
take Heaters in this section. The relays are not energized during engine crank­
ing. When they are energized they make a clicking
noise.

CAUTION:
Do not energize the air intake heater re­
lays
more than
once
per 15
minutes.
If the relays
are
cycled
and the key is turned off and then turned
back
on, the engine
could
be
damaged.
Wait 15

minutes
before
turning the key back to the ON po­

sition.

AIR INTAKE
HEATER
When energized, the air intake heaters warm in­
coming air as it enters the intake manifold. The air
intake heaters (Fig. 13) are energized by the PCM
through the air intake heater relays. Intake manifold air temperature determines when the heaters are en­
ergized. They may be energized before cranking and
after cranking, or both. Refer to Pre-Heat Cycle and
Post-Heat Cycle. The heaters are not energized dur­ ing cranking.
HEATER

RELAYS

WELL
J9114-67

Fig.
12 Air Intake Heater
Relays

Fig.
13 Air Intake Heaters—Typical PREHEAT CYCLE
The PCM powers up when the ignition key is
turned to the On position. If intake manifold air tem­
perature is 15°C (59°F) or below, the intake heaters are energized and the wait-to-start light is illumi­
nated. The heaters are energized for a specific amount of time. This is based on the intake manifold
air temperature. Refer to the Air Intake Heater Cy­
cle Chart.
Once the heaters have cycled, the wait-to-start
light goes out. While the engine is cranked, the heat­
ers are not energized.

POST-HEAT CYCLE
After engine has been started, the post-heat cycle
will begin if intake manifold air temperature was 15°C (59°F) or below when ignition switch was
turned on. Depending upon intake manifold temper­ ature, either: both heaters are energized, or they are
cycled on and off (when one is energized, the other is

not).
The time the heaters are energized depends upon intake manifold air temperature. Refer to the
Air Intake Heater Cycle Chart.

14 - 82
FUEL 'SYSTEM
—. — ~—— — «

INTAKE HEATER CYCLE CHART

Intake
featperafwre
Preheat
Cycle
Time

Ignition
l£ey ON

Engine
Not
Running
Pestheat
Cycle

Ignition
Key ON
Snglne Running

Above
15
°C
(59
°F)
0 Seconds
No

-8°C(18°F)to
15°C (59
°F)
10
Seconds

Yes

-17°C(1
°F)
-9
°C(]6°F)
15
Seconds
Yes

«2d°C(-15°F)
to-18°C(0
°F) 17.5
Seconds
Yes

Below-26
°C (-15
*F)
20 Seconds

Yes

J9114-239
AUTO SHUT DOWN (ASD) RELAY-PCM OUTPUT
The ASD relay is located in the engine compart­
ment (Fig. 14).
TORQUE CONVERTER
CLUTCH RELAY A/C CLUTCH RELAY STARTER RELAY
AUTO SHUTDOWN RELAY FUEL PUMP RELAY DATA LINK
CONNECTOR
POWERTRAIN

CONTROL MODULE
J9314-164

Fig.
14 Relay Location—Typical The ASD relay supplies battery voltage to the gen­
erator field winding to provide regulation of the
charging system. The ground circuit for the ASD re­
lay is controlled by the PCM. The PCM operates the
relay by switching the ground circuit on and off.

MALFUNCTION INDICATOR LAMP-PCM OUTPUT
The malfunction indicator lamp (formerly referred
to as the check engine lamp) illuminates at the bot­
tom of the instrument panel each time the ignition
key is turned on. It will stay on for three seconds as
a bulb test. If the powertrain control module (PCM) receives an
incorrect signal, or no signal from certain sensors or emission related systems, the lamp is turned on. This
is a warning that the PCM has recorded a system or
sensor malfunction. In some cases, when a problem is
declared, the PCM will go into a limp-in mode. This is an attempt to keep the system operating. It signals
an immediate need for service.
The lamp can also be used to display a diagnostic
trouble code (DTC). Cycle the ignition switch
On-Off-
On-Off-On within three seconds and any codes stored
in the PCM memory will be displayed. This is done
in a series of flashes representing digits. Refer to On-
Board Diagnostics in the General Diagnosis section
of this group for more information.

OVERDRIVE
INDICATOR LAMP-PCM OUTPUT
Indicates the state of the overdrive defeat switch
on the instrument panel.

OVERDRIVE
S0LEN0ID-PCM OUTPUT
The overdrive solenoid is used on vehicles that
have an automatic transmission. The solenoid is op­ erated by the PCM. It controls shifting in and out of
overdrive through the overdrive solenoid. Refer to Group 21 for overdrive solenoid service.

SCI
TRANSMIT—PCM OUTPUT
SCI Transmit is the serial data communication
transmit circuit for the DRB II scan tool. The PCM
transmits data to the DRB II through the SCI Trans­
mit circuit.

SPEED
C0NTR0L-PCM OUTPUT
The speed control vacuum and vent solenoids are
operated by the PCM. The vacuum solenoid main­
tains vacuum at a required pressure to resume, set or accelerate the speed control system. The vent so­
lenoid allows vacuum to bleed off during decelera­
tion, when the brakes are applied, or the
transmission is shifted into park or neutral.

TACHOMETER-PCM
OUTPUT
This output generates the necessary signal needed
to operate a dealer installed tachometer (if equipped).
The input for this signal is from the engine speed sensor.

WAIT-TO-START LAMP-PCM OUTPUT
The wait-to-start lamp is turned on and off by the
PCM based on the charge air temperature sensor in­
put. The light is turned on when the ignition is first ac­
tivated. It will remain on for two seconds as a bulb
test. If the PCM reads intake manifold air tempera­
ture below 15°C (59°F), it will turn the wait-to-start light on for the intake heater preheat cycle. The
light stays on until the preheat cycle is over. The wait-to-start light will flash on and off if the
charge air temperature sensor input to the PCM is

•

FUEL SYSTEM
14 - 83 below minimum value or above maximum value. The
PCM stores a DTC when these conditions occur.

WATER-IN-FUEL LAMP-PCM
OUTPUT
The water-in-fuel lamp is turned on and off by the
PCM. The lamp is turned on by the PCM when it re­ ceives an input from the water-in-fuel sensor. The sensor sends an input to the PCM when it detects
water in the fuel/water separator filter.

FUEL DRAIN MANIFOLD
Some fuel is continually vented from the injection
pump to cool the pump and the fuel injectors. During injection, a small amount of fuel flows past the injector nozzle and is not injected
into the combustion chamber. This fuel, along with
the fuel vented from the injection pump, drains into
the fuel drain manifold (Fig. 15). Fuel in the drain manifold is routed back to the fuel tank.

Fig.
15
Fuel
Drain Manifold

FUEL
HEATER
The 5.9L turbo-diesel engine has a fuel heater to
prevent the fuel from waxing in the fuel/water sepa­ rator. The fuel heater is located in the top of the fil­
ter/separator adapter (Fig. 16). The heater has a built in monitor that senses fuel
temperature. Voltage to operate the fuel heater is supplied through the ignition switch. The heater op­
erating range is from 6° - 13.5°C (43° - 53°F).

FUEL
INJECTION PUiVSP
The injection pump is a Bosch VE Distributor type
(Fig. 17). The injection pump is driven by the engine
camshaft. A gear on the end of the pump shaft
meshes with the camshaft gear. The pump is timed
to the engine. Fuel injection occurs near the end of the compression stroke for each cylinder. Refer to In­
jection Pump Removal and Installation in the Diesel Service Procedures section of this group for injection
pump timing procedures.
Fig.
16
Fuel
Heater

Fig.
17 Injection
Pump

The injection pump varies injector timing to corre­
spond with changing engine speed. As engine speed
increases, the internal pump pressure increases. Fuel
flows through an orifice in the advance mechanism
piston (Fig. 18). The piston is opposed by a spring.
The spring regulates injection pump timing advance.
As pump pressure increases, the piston moves against the spring, advancing injection timing. The
spring holds the advance mechanism in the starting
position during cranking and idle.
The mechanical lift pump delivers fuel under a low
pressure of 21-35 kPa (3-5 psi) to the injection pump
through the fuel/water separator filter. The injection
pump supplies high pressure fuel of approximately 59,000 kPa (8,000 psi) to each injector in precise me­
tered amounts at the correct time.
The injection pump contains the KSB (cold start)
solenoid, fuel solenoid, turbo boost control line and
manual shut down valve.

•

FUEL SYSTEM
14-85 to pass through it, but prevents moisture (water)
from doing so. Moisture collects at the bottom of the
separator filter.

WARNING:
EXTINGUISH
ALL
SMOKING
MATERI­
ALS
BEFORE
DRAINING
THE
FUEL/WATER
SEPA­
RATOR
FILTER.

There is a drain at the bottom of the separator fil­
ter (Fig. 16). Place a drain pan under the drain tube.
With the engine not running, push up on the drain
to remove the water from the separator filter. Hold
the drain open until all water and contaminants
have been removed and clean fuel exits the drain. Dispose of mixture in drain pan according to applica­
ble regulations.
Refer to the maintenance schedules in Group 0 in
this manual for the recommended fuel/water separa­
tor filter replacement intervals.

KSB
SOLENOID
The KSB solenoid is not an output of the PCM. The
solenoid is located on the injector pump (Fig. 22). It
contains a valve that controls venting of the injection
pump internal pressure regulator. When voltage is supplied to the solenoid, it closes off the vent circuit
in the injection pump. When the vent circuit is closed
off, internal pump pressure increases and injection
timing advances. The KSB solenoid allows the injec­
tion pump timing to reach full advance sooner. When the KSB solenoid is energized, internal
pump pressure reaches 8 bars (116 psi). When the so­ lenoid is not energized, internal pump pressure should be approximately 4 bars (58 psi). The KSB solenoid circuit contains an air tempera­
ture switch. Battery voltage is supplied to the sole­
noid through the ignition switch. The air temperature switch is mounted on the in­
take manifold next to the charge air temperature sensor (Fig. 23). The air temperature switch is open at or above 32°C (90°F).
Fig.
22 KSB
Solenoid—
Typical
Fig.
23 Air
Temperature
Switch

MANUAL SHUT DOWN LEVER
The injection pump has a manual shut down lever
(Fig. 24). In an emergency, the engine can be shut
down by turning the lever counterclockwise.

Fig.
24 Manual
Shut
Down
Lever

HIGH
PRESSURE FUEL LINES
CAUTION:
High pressure
fuel
lines must
be
held
se­

curely
in
place
in the
holders.
The
lines cannot con­

tact
each other
or
other components.
Do not
attempt
to
weld high pressure
fuel
lines
or to
repair lines
that
are
damaged. Only use
the
recommended
lines when replacement
of
high pressure
fuel
line
is

necessary.

High pressure fuel lines deliver fuel under pressure
of approximately 59,000 kPa (8,000 psi) from the in­
jection pump to the fuel injectors. The lines expand and contract from the high pressure fuel pulses gen­
erated during the injection process. All high pressure
fuel lines are of the same length and inside diameter. Correct high pressure fuel line usage and installation
is critical to smooth engine operation.

14-86
FUEL
SYSTEM

WARNING:
USE
EXTREME CAUTION WHEN
IN­

SPECTING
FOR
HIGH
PRESSURE
FUEL
LEAKS.
IN­

SPECT
FOR
HIGH
PRESSURE
FUEL
LEAKS
WITH
A

SHEET
OF
CARDBOARD. HIGH FUEL INJECTION
PRESSURE
CAN
CAUSE PERSONAL INJURY
IF

CONTACT
IS
MADE
WITH
THE
SKIN.

MECHANICAL
LIFT
PUMP
The mechanical lift pump
is
located
on the
left side
of

the engine cylinder block.
The
lift pump
is
driven
by an
eccentric
on the
camshaft that actuates
a
spring loaded lever
in the
pump
(Fig. 25). The
lever
is
connected
to

the pump diaphragm. When
the
eccentric
on the
cam­ shaft pushes
the
lever upward,
the
lever
in
turn pulls
the diaphragm
to its
extended position. With
the
lever in
the
extended position, fuel
is
drawn into
the
pump
chamber through
the
inlet check valve. When
the
pump
gathers more fuel
in the
fuel chamber than
the
engine
can consume,
the
outlet check valve
is
held closed. Fuel
gathered
in
lift pump chamber prevents
the
diaphragm
from relaxing.
The
lever will continue
to
move
up and

down
on the
shaft connecting
it to the
diaphragm. How­ ever,
it is
prevented from operating
the
diaphragm until
the check valve again opens
and the
fuel
in the
pump chamber
is
expelled. This process continues
as
long
as

the engine
is
running. Minimum lift pump output pressure
is 21 Kpa (3

psi).
Lift pump output volume
is 0.75
liters
(0.70 U.S.
quarts)
per 30
seconds
of
engine cranking.

Fig.
25 Lift
Pump

The lift pump housing
has a
weep hole
at the
bot­
tom
of the
casing
(Fig. 25). If the
diaphragm rup­

tures,
fuel will exit
out of the
weep hole
and the

pump must
be
replaced.
The
lift pump
is not
service­ able
and
must
be
replaced
as a
complete assembly.
CAUTION:
Do not
operate
the
engine
if the
fuel
sup­

ply
line
has a
restriction
of
more than
95 MM Hg

(3.75
in Hg).
The lift pump
has a
manual lever
(Fig. 26). The le­

ver
is
located
on the
lower right side
of the
pump
housing.
The
purpose
of the
lever
is to
prime
the
fuel system
and
bleed
air
from
the
system
if the
vehicle
has
run out of
fuel. Raise
and
lower
the
lever until
resistance
is
felt
to
prime
the
system
up to the
injec­
tor pump. During vehicle operation
the
pump
le­

ver must
be in the up
position.
FUEL
PUMP
MANUAL
JKT /
LEVER
——-—•
.
LJ*y^"^^

J9114-3

Fig.
26 Lift
Pump
Manual
Lever

SYSTEM
OPERATION
IGNITION
SWITCH
ON
When
the
ignition switch
is put in the ON (run)

position,
the
following occurs: •
The PCM
receives
an
ignition sense input.
It
then
powers
up.
Battery voltage
is
supplied through
the

battery voltage input. •
The
wait-to-start lamp
and the
water-in-fuel lamp are turned
on by the PCM for 2.8
seconds
as a
bulb test.
•
The PCM
monitors
the
charge
air
temperature
sensor input.
If
manifold
air
temperature
is at or be­

low
15°C
(59°F),
the PCM
will start
the air
intake
heater preheat cycle.
It
will energize
the
intake heat­
ers
by
grounding
the air
intake heater relays.
The

PCM will turn
the
wait-to-start light
on
until
the

preheat cycle
is
over.
If PCM
receives
a
crank signal
from engine speed sensor before preheat cycle
is
over, it will abort preheat cycle.
•
The PCM
monitors engine speed. When
the
engine speed
is
above
384 rpm, the PCM
determines that
the engine
is
running.
•
The PCM
will turn
on the
water-in-fuel lamp
if a
signal
is
received from
the
water-in-fuel sensor.

ENGINE
START-UP
When
the
ignition
key is put in the
start position,
the following occurs: •
The PCM
receives
a
crank signal input from
the

engine speed sensor.
•
The air
intake heaters
are not
energized during cranking.

•

FUEL
SYSTEM
14 - 87
ENGINE
WARM-UP

• The PCM may start the air intake heater post-heat
cycle depending on intake air temperature. If manifold air temperature was at or below 15°C (59°F) when the
ignition switch was turned on, the cycle is started.
• If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en­ ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 32°C (90°F).
• If the coolant temperature is below 16°C (60° F),
the transmission will not be allowed to enter over­ drive (automatic transmission).
• The PCM will turn on the water-in-fuel lamp if a signal is received from the water-in-fuel sensor.

CRUISE
OR
IDLE

• The PCM monitors intake manifold air tempera­
ture through the charge temperature sensor input. • If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en­ ergized until the air temperature switch opens. The switch opens when intake manifold air temperature
is above 32°C (90°F).
• The air intake heater post-heat cycle will be com­
pleted, if it is not already over.
• The vehicle speed sensor, engine speed sensor and
throttle position sensor inputs are used to control
transmission overdrive operation.
• If the coolant temperature is below 16° C (60° F),
the transmission will not be allowed to enter over­ drive (automatic transmission).
• If the transmission thermo-switch is open, the
transmission will not be allowed to enter into over­
drive (automatic transmission). If the switch opens
when the vehicle is in overdrive, the transmission
will be downshifted. The transmission thermo-switch opens at 134°C (273°F).
• The thermo-switch will close once the transmission
fluid temperature drops to 116°C (240°F). • The PCM will turn on the water-in-fuel lamp if a signal is received from the water-in-fuel sensor.

ACCELERATION
• The vehicle speed sensor, engine speed sensor and
throttle position sensor inputs are used to control
transmission overdrive operation.
• If the coolant temperature is below 16° C (60° F),
the transmission will not be allowed to enter over­
drive (automatic transmission).
• If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en­ ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 32°C (90°F). • If the transmission thermo-switch is open, the
transmission will not be allowed to enter into over­
drive (automatic transmission). If the switch opens
when the vehicle is in overdrive, the transmission
will be downshifted. The transmission thermo-switch opens at 134°C (273°F). The thermo-switch will close
once the transmission fluid temperature drops to 116°C (240°F).
• The PCM will turn on the water-in-fuel lamp if a
signal is received from the water-in-fuel sensor.
• If the speed control system resume/accelerate func­
tion is being used, the PCM will only allow the vehi­
cle to accelerate at a predetermined rate. If a speed
control has been set and the resume/accelerate but­
ton is momentarily pushed in, the PCM will increase
vehicle speed by two miles per hour.
• If the brakes are applied, the PCM will disable the
speed control.

DECELERATION

• The vehicle speed sensor, engine speed sensor and
throttle position sensor inputs are used to control
transmission overdrive operation.
• If the coolant temperature is below 16° C (60° F),
the transmission will not be allowed to enter over­ drive (automatic transmission).
• If the transmission thermo-switch is open, the trans­
mission will not be allowed to enter into overdrive (au­
tomatic transmission). If the switch opens when the
vehicle is in overdrive, the transmission will be down­ shifted. The transmission thermo-switch opens at 134°C (273°F). The thermo-switch will close once the transmis­
sion fluid temperature drops to 116°C (240°F).
• The PCM will turn on the water-in-fuel lamp if a
signal is received from the water-in-fuel sensor.
• If intake manifold air temperature is below 32°C
(90°F),
the KSB solenoid will be energized through
the air temperature switch. The solenoid remains en­ ergized until the air temperature switch opens. The
switch opens when intake manifold air temperature
is above 32°C (90°F).
• If the speed control system coast/set function is be­
ing used, the PCM will only allow the vehicle to de­ celerate at a predetermined rate. If the coast/set
switch is pushed while the system is operating, the
PCM will set speed control to the rate the vehicle is
traveling at when the switch is released. • If the brakes are applied, the PCM will disable the speed control.

IGNITION SWITCH
OFF
• When the ignition switch is turned to the off posi­
tion, the PCM still receives battery voltage through
the battery input. Battery voltage is needed to keep
PCM memory alive. The PCM memory stores diag­ nostic trouble code (DTC) messages and the mini­
mum TPS value from the previous key-on.

DIESEL FUEL INJECTION—GENERAL DIAGNOSIS

INDEX

page

Air
in
Fuel System
90

Air Intake Heater
. 90
Diagnostic
Trouble Code (DTC)
. 95

DRB
II
Scan
Tool
95

Engine
Speed
Sensor
91

Fuel Heater
91

Fuel
Injection
Pump
91

Fuel Injectors
92

Fuel Supply Restrictions
92
page

Fuel/Water Separator
Filter 92

High
Pressure Fuel Line Restrictions
93

KSB
Solenoid
. 93

Mechanical
Lift
Pump
93

On-Board
Diagnostics (OBD)
94
System
Schematics—5.9L Diesel Engine
....... 95

Throttle
Position
Sensor
Test
94
Visual
Inspection
88

VISUAL
INSPECTION
A visual inspection for loose, disconnected, or incor­
rectly routed wires and hoses should be made before attempting to diagnose or service the fuel injection
system. A visual check will help find these condi­

tions.
It also saves unnecessary test and diagnostic

time.
A thorough visual inspection of the fuel injec­
tion system includes the following checks: (1) Be sure that the battery connections are tight
and not corroded (Fig. 1).
• POSITIVE

v^3t
^TERMINAL J91 14
QUICK
DISCONNECT
PCM

MOUNTING
BOLTS

PCM
CONNECTOR CONNECTOR
MOUNTING

BOLT
J9314-165
Fig.
2 Powertrain Control
Module
(PCM)
HEATER

RELAYS
Fig.
1
Battery
Connections
(2)
Be sure that the 60-way connector is fully en­
gaged with the PCM. Verify that the connector
mounting screw is tight (Fig. 2).

(3)
Be sure that the electrical connections at the
air intake heater relays (Fig. 3) are tight and not
corroded.

(4)
Inspect the starter motor and starter solenoid
connections for tightness and corrosion (Fig. 4).
(5)
Verify that the electrical connectors are con­
nected to the charge air temperature sensor and air
temperature switch. Inspect the connectors for corro­ sion or damaged wires (Fig. 5). (6) Verify that the electrical connector is connected
to the air temperature switch (Fig. 5).
WHEEL
^

WELL
J9114-67
Fig.
3 Air Intake Heater
Relays