1993 DODGE TRUCK relay

CLUTCH
6 - 1

CLUTCH

CONTENTS
page

CLUTCH
DIAGNOSIS
2

CLUTCH
COMPONENTS

MECHANICAL COMPONENTS
The clutch mechanism
in
AD
models with
a gas or

diesel engine consists
of a
single, dry-type clutch disc and
a
diaphragm style clutch cover.
A
hydraulic
linkage
is
used
to
engage/disengage
the
clutch disc
and cover.
The transmission input shaft
is
supported
in the

crankshaft
by a
bearing.
A
sleeve type release bear­
ing
is
used
to
operate
the
clutch cover pressure plate.
The release bearing
is
operated
by a
release fork
in

the clutch housing.
The
fork pivots
on a
ball stud
mounted inside
the
housing.
The
release fork
is
actu­ ated
by a
hydraulic slave cylinder mounted
in the

housing.
The
slave cylinder
is
operated
by a
clutch master cylinder mounted
on the
dash panel.
The
cyl­
inder push
rod is
connected
to the
clutch pedal.
The clutch disc
has
cushion springs
in the
disc
hub.

The clutch disc facing
is
riveted
to the hub. The
fac­ ing
is
made from
a
non-asbestos material.
The
clutch
cover pressure plate
is a
diaphragm type with
a one-

piece spring
and
multiple release fingers.
The
pres­ sure plate release fingers
are
preset during
manufacture
and are not
adjustable.
A
265 mm
clutch disc
and
cover
are
used
in
models
with
a 3.9L
engine.
A 280 mm
clutch disc
and
cover are used
in
models with
a 5.2L, or
5.9L engine.
A
330 mm
clutch disc
and
cover
are
used
in
models
equipped with
the
optional
5.9L
Cummins diesel
en­

gine.
Some diesel models
are
also equipped with
a

clutch pedal interlock switch.
The
switch
is in
circuit
with
the
starter relay
and is
actuated
by the
clutch
pedal
and
push
rod. The
clutch pedal must
be
fully depressed
in
order
to
start
the
engine.

HYDRAULIC LINKAGE COMPONENTS
The hydraulic linkage consists
of a
remote reser­
voir, clutch master cylinder, clutch slave cylinder and interconnecting fluid lines.
The clutch master cylinder
is
connected
to the

clutch pedal
and the
slave cylinder
is
connected
to

the clutch release fork.
The
master cylinder
is
mounted
on the
drivers' side
of the
dash panel adja­
cent
to the
brake master cylinder.
page

CLUTCH
SERVICE
11

CLUTCH LINKAGE FLUID
The clutch fluid reservoir, master cylinder, slave
cylinder
and
fluid lines
are
prefilled with fluid
at the

factory during assembly operations. The hydraulic system should
not
require additional
fluid under normal circumstances.
In
fact,
the
reser­
voir fluid level will actually increase
as
normal clutch wear occurs.
For
this reason,
it is
impor­
tant
to
avoid overfilling,
or
removing fluid from
the reservoir. If inspection
or
diagnosis indicates additional fluid
may
be
needed,
use
Mopar brake fluid,
or an
equiv­
alent meeting
SAE and DOT
standards J1703
and

DOT
3. Do not use any
other type
of
fluid.

CLUTCH
COMPONENT LUBRICATION
Proper clutch component lubrication
is
important
to satisfactory operation.
The
correct lubricant
and
not overlubricating
are
equally important. Apply rec­
ommended lubricant sparingly
to
avoid disc
and
pres­ sure plate contamination. Clutch
and
transmission components requiring
lu­

brication
are:
• pilot bearing
• release lever pivot ball stud
• release lever contact surfaces
• clutch disc
hub
splines
• clutch pedal pivot shaft bore
• clutch pedal bushings
• input shaft splines
• input shaft pilot
hub

• transmission front bearing retainer slide surface Do
not
apply grease
to any
part
of the
clutch
cover,
or
disc.

RECOMMENDED LUBRICANTS
Use Mopar multi-purpose grease
for the
clutch
pedal bushings
and
pivot shaft.
Use
Mopar high tem­
perature grease
(or
equivalent)
for all
other lubrica­
tion requirements. Apply recommended amounts
and
do
not
over lubricate.

•

ELECTRICAL
8A - 9
ENGINE STARTER MOTOR TEST PROCEDURES
GENERAL INFORMATION
The starting system consists of an:
• ignition switch
• starter relay
• park/neutral position switch (automatic transmis­ sion)
• clutch switch (diesel engine-manual transmission)
• wiring harness
• battery
• starter motor with an integral solenoid. These components form 2 separate circuits. A high
amperage circuit that feeds the starter motor up to
300+ amps-gas engine; 500+ amps-diesel engine,
and a control circuit that operates on less than 20
amps (Fig. 1).
a.
BATTERY +
1
IGNITION
SWITCH 1 AUTOMATIC TRANSMISSION
•
J
NEUTRAL SAFETY SWITCH
I 4-
"JL"
MOTOR
m, ...
STA3-TERSOLENO,Dnlh
STARTER RELAY

1"

898A-14
Fig.
1 Starting
System
Components

STARTER SYSTEM DIAGNOSTIC INSPECTIONS
Before removing any unit from the starter motor
system for repair, perform the following inspections:

BATTERY
INSPECTION
To determine condition of the battery, perform the
testing procedure outlined in the Battery Section.

WIRING INSPECTION
Inspect wiring for damage. Inspect all connections
at the starter motor solenoid, park/neutral position
switch (if equipped), back-up lamp switch connector,
ignition/start switch, and battery (including all
ground connections). Clean and tighten all connec­
tions as required.

SOLENOID, RELAY
AND
IGNITION/START

SWITCH
INSPECTION
Inspect the solenoid, relay and switch to determine
their condition. Also, if equipped with automatic
transmission, inspect condition of the park/neutral position switch. Testing information can be found in
the following pages.
If the following components are working properly
remove the starter motor and follow procedures in
the Testing Section. • battery wiring
switch
solenoid
relay
park/neutral position switch

COLD CRANKING TEST
(1) Battery must first pass load and voltage drop
tests and be fully charged before proceeding. Refer to Battery Test Procedures. (2) Connect a suitable volt-ampere tester to the
battery terminals (Fig. 2). Refer to the operating in­ structions provided with the tester being used.
POSITIVE
CLAMP

898A-15
NEGATIVE
CLAMP
INDUCTION
AMPMETER
CLAMP
Fig.
2
Volt-Amps
Tester
Connections
(Typical)

(3) Fully engage parking brake, place manual
transmission in NEUTRAL, automatic transmission
in PARK. (4) Verify that all lights and accessories are OFF. (5) Remove coil secondary cable from distributor
and connect to ground.
(6) Rotate and hold the ignition switch (key) in the
START position. Note cranking voltage and amper­
age.
(a) If voltage reads above 9.6 volts and amperage
draw reads above (220 amps gas engine) (550 amps
diesel) go to Starter Feed Circuit Tests. (b) If voltage reads 12.5 volts or greater and am-
perate reads 0 to 10 amps, go to Starter Control Circuit Tests.
A cold engine will increase starter motor cur­
rent.

STARTER
FEED
CIRCUIT TESTS
-
(W0LTAGE
DROP
METHOD)
The voltage drop tests will determine if there is ex­
cessive resistance in the high current circuit. When
performing these tests, it is important that the volt­ meter be connected to the terminals that the cables are connected to instead of to the cables themselves.
For example, when testing between the battery and
solenoid, touch the voltmeter test probes to the bat-

8A
- 10
ELECTRICAL
•
STARTING SYSTEM DIAGNOSIS

TEST CONDITIONS • PLACE GEAR SELECTOR
IN
PARK OR NEUTRAL AND SET PARK BRAKE
OR
EQUIVALENT. • VERIFY BATTERY STATE-OF-CHARGE AND CRANKING CAPACITY, SEE BATTERY SECTION.
• CLEAN BATTERY TOP, POSTS, AND TERMINALS.
• VERIFY ALTERNATOR DRIVE BELT TENSION.
• DISCONNECT AND GROUND COIL CABLE. SYMPTOM
SYMPTOM SYMPTOM SYMPTOM SYMPTOM
STARTER FAILS TO STARTER FAILS TO STARTER ENGAGES, STARTER ENGAGES STARTER DOES NOT

ENGAGE.
NO SOUNDS
ENGAGE
SOLENOID FAILS TO TURN DRIVE CLUTCH

DISENGAGE
AFTER
OR RELAY CLICKS ENGINE. DOME
LIGHT
SPINS
OUT
ENGINE STARTS

DIMS

POSSIBLE
CAUSE
POSSIBLE
CAUSE
POSSIBLE
CAUSE
POSSIBLE
CAUSE
POSSIBLE
CAUSE
STARTER CONTROL
RESISTANCE
TOO
RESISTANCE
TOO DRIVE CLUTCH
FAULTY

IGNITION
SWITCH
CIRCUIT
FAULTY
HIGH
IN
STARTER
HIGH
IN
STARTER

FAULTY

FEED CIRCUIT FEED CIRCUIT

BROKEN
TEETH

IGNITION
SWITCH ON RING GEAR
STARTER RELAY

FAULTY
STARTER CONTROL STARTER ASSEMBLY

FAULTY

CIRCUIT
FAULTY FAULTY

STARTER ASSEMBLY
PARK/NEUTRAL
FAULTY

STARTER ASSEMBLY
POSITION STARTER SOLENOID ENGINE

FAULTY

SWITCH
FAULTY

SEIZED

(AUTO
TRANS.) STARTER

FAULTY
OR STARTER
MISADJUSTED STARTER ASSEMBLY IMPROPERLY

FAULTY
MOUNTED
STARTER RELAY
REFER
TO

FAULTY
APPROPRIATE GROUP
AND SECTION OF THIS
MANUAL FOR PROPER
STARTER ASSEMBLY
SERVICE
AND TEST

FAULTY
PROCEDURES
FOR THE
COMPONENTS INVOLVED

J938A-9
tery post and the solenoid threaded stud. The follow­
ing operation will require a voltmeter, accurate to 1/10 of a volt.
Before performing the tests, assure the following
procedures are accomplished:
•
Disconnect the distributor connector (gas engine).

•
Disconnect both wires on the fuel solenoid (diesel engine) (Fig. 3). Verify that:

•
all lights and accessories are OFF

•
transmission shift selector is in PARK (automatic)
or NEUTRAL (manual)

•
parking brake is applied

•
battery is fully charged (refer to Battery Test Pro­
cedures). (1) Connect positive lead of voltmeter to battery
negative post. Connect negative lead of voltmeter to
battery negative cable clamp (Fig. 4). Rotate and
Fig.
3
Diesel
Engine
Fuel
Solenoid

•

ELECTRICAL
8A - 11 hold the ignition switch (key) in the START position.
Observe the voltmeter. If voltage is detected, correct
poor contact between the cable clamp and post.
VOLTMETER

VOLTMETER

BATTERY
898A-17

Fig.
4 Test
Battery
Connection
Resistance
(2) Connect positive lead of voltmeter to battery
positive post. Connect negative lead of voltmeter to
battery cable positive clamp (Fig. 4). Rotate and hold
the ignition switch (key) in the START position. Ob­ serve the voltmeter. If voltage is detected, correct
poor contact between the cable clamp and post.
(3) Connect a voltmeter to measure between the
battery positive post and the center of the B + starter solenoid stud (Fig. 5).

BATTERY
STARTER
MOTOR
VOLTMETER

898A-20

Fig.
5 Test Positive
Battery
Cable
Resistance
(Typical)

(4) Rotate and hold the ighition with (key) in the
START position. If voltage reads above 0.2 volt, cor­
rect poor contact at battery cable to solenoid connec­

tion.
If reading is still above 0.2 volt, replace positive
battery cable.
(5) Connect the voltmeter to measure between the
battery negative post and the engine block (Fig. 6).
(6) Rotate and hold the ignition with (key) in the
START position. If voltage reads above 0.2 volt, cor­
rect poor contact at ground cable attaching point.
Voltage reading still above 0.2 volt, replace ground cable.
ENGINE
, ^J^P

GROUND
\
BATTERY
898A-18

Fig.
6 Test
Ground
Circuit
Resistance
(7)
Connect positive voltmeter lead to starter mo­
tor housing. Connect negative lead of voltmeter to
battery negative terminal (Fig. 7).
STARTER

MOTOR
BATTERY

VOLTMETER
898A-26

Fig.
7 Test
Starter
Motor
Ground
(Typical)
(8) Rotate and hold the ignition switch (key) in the
START position. If voltage reads above 0.2 volt, cor­
rect poor starter to engine ground.
If resistance tests detect no feed circuit failures, re­
move the starter motor and go to Bench Testing Starter Solenoid.

STARTER
CONTROL
CIRCUIT
TESTS
The starter control circuit consists of a:
• starter solenoid
• starter relay
• ignition switch
• park/neutral position switch (automatic transmis­ sion)
• clutch switch (diesel engine-manual transmission)
• all their wiring and connections.
Testing procedures for these components are as fol­
lows and should be followed in order as described.

CAUTION:
Before
performing
any
test,
disconnect

distributor
connector
to
prevent
engine
from
start­
ing.
Disconnect
both
wires
on
fuel
solenoid
(diesel
en­

gine).

8A
- 12
ELECTRICAL

•

ENGINE
STARTER
RELAY
STARTER RELAY CONNECTIONS
GROUND SOLENOID (85) TERMINAL
(87) J928B-1

RELAY OPERATION/TESTING

OPERATION

• The Battery terminal is connected to battery volt­
age (B +
)
at all times.
• The Solenoid terminal is connected to the battery
terminal in the energized position which supplies
battery voltage to the operated device. • The Ignition terminal is connected to the electromag­
net and usually connected to a switched power source.
• The Ground terminal is connected to the electro­
magnet and is usually grounded by a switch or PCM.

TESTING
• Resistance value between the ground and ignition
terminals (electromagnet) is
75
±5 ohms for resistor
relays and 86±5 ohms for diode relays.
• Connect a battery to the ignition terminal and
connect ground to the ground terminal. There should
be continuity between the battery and solenoid ter­ minals (contact closed).
ENGINE STARTER RELAY REPLACEMENT The starter relay is located on the driver's side in­
ner fender (Fig. 8).
PART THROTTLE
A/C
CLUTCH STARTER AUTO SHUT
UNLOCK RELAY RELAY RELAY DOWN RELAY
Fig.
8
Starter
Relay
(1) Replace the relay as required.
(2) Test relay operation. IGNITION SWITCH TEST
After testing starter solenoid and relay and they
check out okay, trouble is probably with ignition
switch or its wiring. Check all wiring for opens and shorts and connec­
tions for being loose or corroded.
BENCH TESTING STARTER SOLENOID Refer to Group 8B - Battery Starter Service for
starter removal procedures. (1) Disconnect field coil wire from field coil termi­
nal (Fig. 9).

Fig.
9 Field
Coil
Wire
Terminal
(2) Check for continuity between solenoid terminal
and field coil terminal with a continuity tester.
There should be continuity (Fig. 10).

Fig.
10 Continuity Test Between
Solenoid
Terminal
and
Field
Coil
Terminal
(3) Check for continuity between solenoid terminal
and solenoid housing. There should be continuity
(Fig. 11).
SOLENOID

RR8BD33 Fig.
11 Continuity Test Between
Solenoid
Terminal

and Solenoid Case

(4) If there is continuity solenoid is good. If there
is no continuity in either test solenoid has an open
circuit and is defective. Replace the starter motor. (5) Install starter as described in Group 8B - Bat­
tery Starter Service. (6) Connect field coil wire to field coil terminal
(Fig. 9).

•

ELECTRICAL
8A - 13 GENERATOR TEST PROCEDURES ON
VEHICLE

INDEX

page
Current
Output
Test
......................
14
Diagnostic Procedures
13

General
Information
13
Generator
Output
Wire Resistance Test
.......
13
page
How
to
Use
Malfunction
Indicator
(Check Engine) Lamp
for
Fault
Codes
17

Operational Check
with
Voltmeter
............
13
Using
On-Board Diagnostic System
15

GENERAL
INFORMATION
The generator
is
belt-driven
by the
engine.
All en­

gines
use
serpentine drive. The amount
of DC
current produced
by the
gener­
ator
is
controlled
by the
Powertrain Control Module (PCM).
All vehicles
are
equipped with
On
Board Diagnos­
tics (OBD).
All OBD
sensing systems
are
monitored
by
the PCM. The PCM
will store
in
electronic mem­ ory
any
detectable failure within
the
monitored cir­

cuits.
Refer
to
USING ON-BOARD DIAGNOSTIC SYSTEM
in
this group
for
more information.

OPERATIONAL CHECK
WITH
VOLTMETER
When
the
ignition switch
is
turned
to the RUN po­

sition, battery potential will register
on the
voltme­
ter. During engine cranking
a
lower voltage will appear
on the
meter. With
the
engine running,
a

voltage reading higher than
the
first reading (igni­
tion
in RUN)
should register.

DIAGNOSTIC PROCEDURES
If
the
indicator does
not
operate properly,
or if an

undercharged
or
overcharged battery condition
oc­

curs,
the
following procedures
may be
used
to
diag­
nose
the
charging system. Remember that
an
undercharged battery
is
often
caused
by:
• accessories being left
on
overnight
•
or by a
defective switch which allows
a
bulb, such
as a
trunk
or
glove
box

light,
to
stay
on
(refer
to
Ignition
Off
Draw).
WISUAL
INSPECTION

• Inspect condition
of
battery cable terminals, bat­
tery posts, connections
at
engine block, starter motor solenoid
and
relay. They should
be
clean
and
tight.
Repair
as
required.
• Inspect
all
fuses
in the
fuse block
for
tightness
in

receptacles. They should
be
properly installed
and

tight. Repair
or
replace
as
required.
• Inspect generator mounting bolts
for
tightness.
Re­

place
or
torque bolt
as
required (refer
to
Torque Specifications).
• Inspect generator drive belt condition
and
tension.
Tension
or
replace belt
as
required. Refer
to
Belt
Tension Specifications. • Inspect connection
at
generator
B+
output.
It

should
be
clean
and
tight. Repair
as
required.

GENERATOR
OUTPUT
WIRE RESISTANCE TEST
(FIG.
1)
Generator output wire resistance test will show
amount
of
voltage drop across generator output wire
between generator
BAT
terminal
and
battery posi­ tive post.

PREPARATION
(1) Before starting test make sure vehicle
has a

fully charged battery. Test
and
procedures
on how to
check
for a
fully charged battery
are
shown
in
Bat­
tery section
of
this Group.
(2) Turn
OFF
ignition switch.
(3)
Disconnect negative cable from battery.

(4)
Disconnect generator output wire from genera­
tor output Battery terminal. (5) Connect
a 0-150
ampere scale
D.C.
ammeter
in

series between generator
BAT
terminal
and
discon­
nected generator output wire. Connect Positive lead
to generator
BAT
terminal
and
Negative lead
to
dis­ connected generator output wire. (6) Connect Positive lead
of a
test voltmeter
(Range
0-18
volts minimum)
to
disconnected genera­
tor output wire. Connect negative lead
of
test voltme­
ter
to
battery positive cable
at
positive post. (7) Connect
one end of a
Jumper Wire
to
ground
and with other
end
probe green
K20
lead wire
at

back
of
generator
(Fig. 1).
(This will generate
a
fault
code).

CAUTION:
Do not
connect blue
A142
lead
of
wiring
to ground. Refer
to
Group
8W
-
Wiring Diagrams
for
more information.

(8) Connect
an
engine tachometer
and
connect neg­
ative cable
to
battery.
(9) Connect
a
variable carbon pile rheostat
be­

tween battery terminals.
Be
sure carbon pile
is in
"Open"
or "Off
position before connecting leads.
See

Battery Section, Load Testing
for
instructions.

TEST
(1) Start engine. Immediately after starting,
re­

duce engine speed
to
idle.

8A
- 14
ELECTRICAL

CASE
GROUND
FIELD

TERMINALS

142-DG/OR
BATTERY
VOLTAGE


ALTERNATOR
CASE

GROUND
GROUND ALTERNATOR
BATTERY
TERMINAL
ENGINE
CONTROLLER TO ENGINE
CONTROLLER TERMINAL
51

LESS
THAN

"BATTERY VOLTAGE
m^mm i
A21 DB-
20
AMP FUSE
A14
RD


AUTO

SHUTDOWN
RELAY
IGNITION
SWITCH

POWER

DISTRIBUTION
CENTER
JUMPER WIRE TO GROUND TEST
AMMETER TEST

VOLTMETER
2
i

DISCONNEaED

ALTERNATOR
OUTPUT
WIRE
ACC

OFF
J938A-17
CARBON
PILE
RHEOSTAT
Fig.
1 Generator Output
Wire
Resistance
Test
(Typical)

(2) Adjust engine speed and carbon pile to main­
tain 20 amperes flowing in circuit. Observe voltmeter
reading. Voltmeter reading should not exceed 0.5
volts.

RESULTS
If a higher voltage drop is indicated, inspect, clean
and tighten all connections between generator BAT
terminal and battery Positive post. A voltage drop
test may be performed at each connection to locate
connection with excessive resistance. If resistance
tested satisfactorily, reduce engine speed, turn off carbon pile and turn off ignition switch.
(1) Disconnect negative cable from battery.
(2) Remove test ammeter, voltmeter, carbon pile,
and tachometer. (3) Remove "Jumper Wire".
(4) Connect generator output wire to generator
BAT terminal post. Tighten to 5 to 6 Nnn (45 to 75

in.
lbs.). (5) Connect negative cable to battery.
(6) Use DRB II Scan Tool to erase diagnostic trou­
ble code.

CURRENT
OUTPUT
TEST
Current output test determines whether or not gen­
erator is capable of delivering its rated current out­
put.
PREPARATION

(1) Before starting any tests make sure vehicle has
a fully charged battery. Test and procedures on how
to check for a fully charged battery are shown in
Battery section of this Group,
(2) Disconnect negative cable from battery.
(3) Disconnect generator output wire at the gener­
ator battery terminal.
(4) Connect a 0-150 ampere scale D.C. ammeter in
series between generator BAT terminal and discon­
nected generator output wire (Fig. 2). Connect posi­
tive lead to generator BAT terminal and negative
lead to disconnected generator output wire.
(5) Connect positive lead of a test voltmeter (range
0-18 volts minimum) to generator BAT terminal.
(6) Connect negative lead of test voltmeter to a
good ground.
(7) Connect an engine tachometer and connect neg­
ative cable to battery.
(8) Connect a variable carbon pile rheostat be­
tween battery terminals. Be sure carbon pile is in Open or Off position before connecting leads. See
Battery section, Load Testing for instructions.
(9) Connect one end of a Jumper Wire to ground
and with other and probe green K20 lead wire at
back of generator (Fig. 2). (This will generate a fault
code).

•

ELECTRICAL
8A - 15 a

CASE
GROUND
CAPACITOR
ALTERNATOR ~L FIELD
TERMINALS

A
142-DG/OR BATTERY
VOLTAGE K20-DG
—!

GROUND
CASE

GROUND
til

ALTERNATOR BATTERY
TERMINAL ENGINE
CONTROLLER TO ENGINE
CONTROLLER TERMINAL
51

LESS
THAN
BATTERY VOLTAGE A21
DB-
.....
IGNITION SWITCH
20 AMP FUSE
AUTO
AH ^

SHUTDOWN POWER
RELAY
DISTRIBUTION

\
CENTER TEST
AMMETER JUMPER WIRE
TO GROUND
TEST
VOLTMETER
GO
5—n
DISCONNECTED
ALTERNATOR OUTPUT WIRE GROUND

ACC
Bl
OFF
RUN OFF
START*T

|ACC

CARBON
PILE RHEOSTAT
J938A-18

Fig.
2 Generator Current Output Test—Typical

CAUTION:
Do not
connect
blue
A142
lead
of
wiring

to ground.
Refer
to
Group
8W -
Wiring
Diagrams
for
more
information.

TEST
(1) Start engine. Immediately after starting reduce
engine speed to idle. (2) Adjust carbon pile and engine speed in incre­
ments until a speed of 1250 rpm and voltmeter read­
ing of 15 volts is obtained.

CAUTION:
Do not
allow
voltage
meter
to
read
above
16 volts.

(3) The ammeter reading must be within limits
shown in generator specifications in back of this
group for that size of generator being tested.

RESULTS
(1) If reading is less than specified and generator
output wire resistance is not excessive, the generator
should be replaced. Refer to Group 8B - Generator
Service for information.
(2) After current output test is completed reduce
engine speed, turn off carbon pile and turn off igni­
tion switch.
(3) Disconnect negative cable from battery. (4) Remove test ammeter, voltmeter, tachometer
and carbon pile. (5) Remove Jumper Wire (Fig. 2).
(6) Connect generator output wire to generator
BAT terminal post. Tighten nut to 5-6 Nnn (45-75 in.

lbs.).

(7) Connect negative cable to battery.
(8) Use DRB II Scan Tool to erase diagnostic trou­
ble code.

USING
ON-BOARD
DIAGNOSTIC
SYSTEM
OPERATION
OF
ON-BOARD
DIAGNOSTIC

SYSTEM

The Powertrain Control Module monitors critical
input and output circuits of the charging system
making sure they are okay. Some are checked contin­
uously and some are only checked under certain con­
ditions.
If the OBD system senses that one of the critical
circuits is bad, it will consider this a real problem
and put a DTC into memory. Each input and output
circuit monitored by the OBD system has its own

DTC.
The DTC will stay in memory as long as the
circuit continues to be bad. If the problem does not
occur again after the code is put into memory, the
Powertrain Control Module will clear the memory af­
ter 50 to 100 engine starts.