1993 DODGE TRUCK fuel pressure

21 - 52 G360
MANUAL
TRANSMISSION

• (12) Disconnect wires at vehicle speed sensor and
backup light switch.
(13) Disconnect transfer case shift lever from lever
on transfer case.
(14) Temporarily support transmission with adjust­
able jack stand. Then support transfer case with
transmission jack.
(15) Remove nuts attaching transfer case to trans­
mission adapter and move transfer case away from
transmission rear retainer.
(16) Lower transfer case and move it from under
vehicle. Remove transfer case from transmission jack and place transfer case on workbench.
(17) Support transmission with transmission jack.
Secure transmission to jack with safety chains. Then
remove jack stand previously used to support trans­
mission.
(18) Spread clamps that secure switch wires to
transmission top cover and remove wires from clamps. Move wires aside to protect them and pro­
vide working clearance.
(19) Remove bolts attaching transmission rear
mount to crossmember.
(20) On some models, it is necessary to remove
screws attaching fuel line clamps to driver side
frame rail. Three clamps must be removed to so fuel lines can be moved for access to crossmember bolts at
this side of frame rail.
(21) Remove left and right crossmember-to-frame
braces and remove crossmember.
(22) Remove clutch slave cylinder shield.
(23) Loosen clutch slave cylinder attaching nuts
until cylinder piston rod is clear of release lever (Fig.

20).
This reduces pressure on lever and release bear­
ing making transmission removal/installation easier. Cylinder does not have to be removed completely.
(24) Remove bolts attaching transmission to clutch
housing and remove transmission. Rock transmission slightly to help free input shaft from clutch disc and
release bearing.
(25) Support engine with wood block and another
adjustable jack stand.

TRANSMISSION
INSTALLATION—4-WHEEL
DRIVE
(1) Mount transmission on jack stand. Secure
transmission to jack with safety chains.
(2) Apply light coat of Mopar high temperature
bearing grease to contact surfaces of input shaft (Fig. 20) and following components:

CAUTION:
Do not use
excessive
amounts
of
grease.

This
practice
could
result in contamination of the

clutch
disc.

• input shaft splines and pilot bearing hub
• release bearing slide surface of front retainer
• pilot bushing
• release bearing bore
• release fork
• release fork ball stud • propeller shaft slip yoke
(3) Align transmission and clutch housing. Move
transmission forward and start input shaft into re­ lease bearing and hub of clutch disc. (4) Rotate output shaft with socket or yoke to align
input shaft and clutch disc splines. If input shaft will
not rotate enough in neutral to align splines, it will
be necessary to shift transmission into third or fourth gear with screwdriver. (5) Seat transmission against clutch housing and
align bolt holes in transmission and housing. (6) Install and tighten transmission-to-clutch hous­
ing bolts to 68 N-m (50 ft. lbs.). (7) Install rear crossmember and mount. Start all
crossmember bolts/nuts then tighten them to 68 N*m (50 ft. lbs.) torque. (8) Remove transmission jack.
(9) Install screws that attach fuel line clamps to
driver side frame rail. (10) Align clutch slave cylinder in housing and
tighten cylinder attaching nuts. (11) Install clutch slave cylinder shield.
(12) Secure backup light and vehicle speed sensor
wires in clips at top of transmission. Route wires across top of transmission to sensor and switch and
connect wires.
(13) Install gasket and transfer case on transmis­
sion rear retainer. Tighten transfer case attaching
nuts to 47 N-m (35 ft. lbs.) torque. (14) Check transmission and transfer case lubri­
cant levels. Add lubricant if necessary and install fill

plugs.

(15) Connect transfer case shift lever to lever on
transfer case.
(16) Align and install propeller shafts. Tighten
U-joint clamp bolts to 19 N-m (14 ft. lbs.). (17) Install skid plate and crossmember. Tighten
skid plate and crossmember bolts/nuts to 41 N—m
(30 ft. lbs.) torque.
(18) Lower vehicle.
(19) Shift transmission into neutral if necessary.
(20) Lubricate shift lever ball and collar with Mo­
par all purpose grease. (21) Align notches in shift lever ball and collar
and insert shift lever in shift tower. (22) Press shift lever and collar downward and in­
stall shift lever snap ring. (23) Install boot over shift lever and onto shift
tower and tighten boot clamp securely. (24) Install lower boot and plate assembly over
shift lever and onto floorpan. Position plate so large
notch is forward then install lower boot attaching screws. (25) Thread or bolt shift lever extension to shift le­
ver. Slide upper boot down extension. Position boot on plate and install boot attaching screws. (26) Install shift knob on extension (if removed).
(27) Connect battery negative cable.

22 - 2
WHEELS
AND
TIRES

•

METRIC
TIRE
SIZES
P
205 / 75 I 15

J9322-6
Fig.
1
Tire
Size
identification
TIRE
CHAINS

Tire snow chains may be used on certain models.
Refer to Owner's Manual for more information.

CLEANING
OF
TIRES
Steam cleaning may be used for cleaning.
DO NOT use gasoline or wire brush for cleaning.
DO NOT use mineral oil or an oil-based solvent.

PRESSURE GAUGES
High-quality, dial-type, air-pressure gauges are
recommended. After checking with the gauge, re­
place valve caps and tighten finger tight.

TIRE
INFLATION
PRESSURES
Under inflation (Fig. 2) causes rapid shoulder wear
and tire flexing. Over inflation (Fig. 3) causes rapid center wear
and loss of the tire's ability to cushion shocks. Improper inflation can cause;
• Uneven wear patterns
• Reduced tread life
• Reduced fuel economy
• Unsatisfactory ride
• Cause the vehicle to drift Refer to the Owner's Manual for information re­
garding proper tire inflation pressure. This pressure has been carefully selected to provide
for safe vehicle operation. Tire pressure should be
Fig.
2
Under
infiation
Wear

Fig.
3
Over
Infiation
Wear
checked cold once per month. Tire pressure de­ creases when the outside temperature drops.
Inflation pressures specified on the placards are al­
ways cold
inflation
pressure. Cold inflation pres­ sure is obtained after the vehicle has not been
operated for at least 3 hours. Tire inflation pressures may increase from 2 to 6 pounds per square inch (psi) during operation. Do not reduce this normal
pressure build-up.
Vehicles loaded to the maximum capacity should
not be driven at continuous speeds above 75 mph (120 km/h).

WARNING: OVER
OR
UNDER INFLATED TIRES
CAN
AFFECT VEHICLE HANDLING
AND CAN
FAIL
SUD­ DENLY, RESULTING
IN
LOSS
OF
VEHICLE CON­
TROL
REPLACEMENT TIRES
OEM tires provide a proper balance of many fea­
tures such as; • Ride

EMISSION
CONTROL SYSTEMS
25 - :

CALIFORNIA VEHICLE EMISSION CONTROL INFORMATION LABEL-TYPICAL

or,

o_ UJ
u_

U
^
>
CO

CQ

o
IMPORTANT
VEHICLE
INFORAAATION

THIS VEHICLE CONFORMS
TO
U.S.
EPA AND STATE
OF
CALIFORNIA REGULATIONS APPLICABLE
TO 1993
MODEL YEAR NEW
LIGHT-DUTY

TRUCKS
AND
MEDIUM-DUTY VEHICLES PROVIDED
THAT
THIS VEHICLE
IS
ONLY INTRODUCED
INTO
COMMERCE FOR
SALE
IN THE

STATE
OF
CALIFORNIA.
*
BASIC
IGNITION TIMING
AND
IDLE FUEL/AIR
MIXTURE HAVE BEEN
PRESET
AT THE
FACTORY.
SEE THE
SERVICE MANUAL
FOR
PROPER
PROCEDURES
AND
OTHER
ADDITIONAL
INFORMATION.

o
ADJUSTMENTS MADE
BY
OTHER
THAN
APPROVED
SERVICE MANUAL PROCEDURES
MAY
VIOLATE
FEDERAL
AND
STATE
LAWS.

CAUTION:
APPLY
PARKING BRAKE
WHEN
SERVICING
VEHICLE.
5.2
LITER

PCR360T5FHB2
PTAPG
SPARK
PLUGS

.035
in.
GAP RC12YC NO ADJUSTMENTS NEEDED

RHC/CO/NOx
STDS.
.50/9.0/1.0
TEE
CONNECTOR

W/ORIFICE
TO

ATMOSPHERE
ROLLOVER
VALVE

W/ORIFICE

/

PCV
VALVE-

TO
CLIMATE
CONTROL,

VEHICLE SPEED
CONTROL,
4X4
AXLE

(WHEN
EQUIPPED)

INTAKE
MANIFOLD"
ORIFICE
—
M

r-
M
EVAP
PURGE

SOLENOID
FILTER
THROTTLE
BODY
FUEL
TANK PRESSURE
RELIEF/

ROLLOVER
VALVE
W/ORIFICE

FUEL

PRESSURE

REGULATOR
1

r—O
O^-CRANKCASE
TO
AIR

CLEANER
APPLICABLE
TO
35

GALLON
FUEL
TANK
ONLY
J9325-23

CANADA VEHICLE EMISSION CONTROL INFORMATION LABEL-ATYPICAL
VEHICLE
EMISSION
CONTROL
INFORAAATION

THIS
VEHICLE
WAS
BUILT
FOR
SALE
IN
CANADA
AND WAS
DESIGNED
TO
MEET
THE
EMISSION
REQUIREMENTS
OF THE
CANADA
MOTOR
VEHICLE
ACT.
IT
WAS NOT
DESIGNED
TO
COMPLY
WITH
THE

REQUIREMENTS
OF
OTHER
COUNTRIES.

'
BASIC
IGNITION TIMING
AND
FUEL
INJECTION
MIXTURE HAVE BEEN
PRESET
AT
THE
FACTORY.
ADJUSTMENTS
SHOULD
NOT
BE
MADE
DURING
ROUTINE
SERVICE.

CAUTION:
APPLY
PARKING BRAKE
WHEN
SERVICING
VEHICLE.
5.2
LITRES

SPARK
PLUGS
0.9
mm GAP
RC12YC

RENSEIGNEMENTS RELATIFS
AU
SYSTEME
ANTIPOLLUTION

LE
PRESENT
VEHICULE
A
ETE
FABRIQUE'
POUR ETRE
VENDU
AU
CANADA
ET
IL
A
ETE
CONCU
DE

MANIERE
A
SE
CON
FORMER
AUX
NORMES
ANTIPOLLUTION
DE LA LOI SUR LA
SECURITE
DES
VEHICULES
AUTOMOBILES
DU
CANADA.
IL
N'EST
PAS
DESTINE'
A SE
CON
FORMER
AUX
NORMES
D'AUTRES
PAYS.

*
LE
CALAGE
DE
L'ALLUMAGE
INITIAL
ET LE
MELANGE
D'INJECTION
D'ESSENCE
ONT
ETC:
PREREGLE'S
A
L'USINE.
N'EFFECTUEZ
AUCUN
REGLAGE
LORS
DE
TRAVAUX
D'ENTRETIEN
REGULIERS.

AVERTISSEMENT:
SERREZ
LE
FREIN
DE
STATIONNEMENT
POUR
FAIRE
L'ENTRETIEN
OU
LA
RE'PARATION
DU
VEHICULE.
5.2
LITRES

,
BOUGIES

ECARTEMENT
0.9 mm
RC12YC

ROLLOVER VALVE W/ORIFICE CLAPET DE DECHARGE AVEC AJUTAGE EVAP PURGE SOLENOID

E'LECTROVALVE
DE
_
FUEL TANK PURGE
DU
FILTRE RESERVOIR
D'ESSENCE
-

A CHARBON ACTIF /
TO CLIMATE CONTROL,
VEHICLE SPEED CONTROL.
4X4 AXLE (WHEN EQUIPPED)
VERS LA COWMAN DE
DE

TEMPERATURE. LE REGULATEUR DE VITESSE, LESSIEU
4X4 (LORSQU'AINSI EQUIPE')
INTAKE MANIFOLD ORIFICE AJUTAGE DE LA TUBULURE D'ADMISSION FUEL TANK PRESSURE RELIEF/
I

ROLLOVER VALVE W/ORIFICE
CLAPET DE DECHARGE
DU
RESERVOIR D'ESSENCE AVEC AJUTAGE FUEL PRESSURE REGULATOR
REGULATEUR DE PRESSION DE CARBURANT CHECK VALVE W/ORIFICE
SOUPAPE
A
DOUBLE EFFET
-
AVEC AJUTAGE AAAP SENSOR
"

CAPTEUR DE PRESSION
ABSOLUE DE LA TUBULURE THROTTLE BODY
CORPS DE PAPILLON APPLICABLE
TO
35

GALLON FUEL TANK ONLY
UNIQUEMENT APPLICABLE
AU

RESERVOIR D'ESSENCE DE
132
L

2i
- 4
EMISSION
CONTROL
SYSTEMS

•
VACUUM
HOSE
ROUTING
SCHEMATICS

The following vacuum hose routing schematics
are used
as
examples only.
If
there
are any
differ­
ences between these schematics
and the
Vehicle
Emission Control Information (VECI) label schemat­

ics,
those shown
on the
VECI label should
be
used.
ENGINE
VACUUM
SCHEMATIC-3.9U5.2L/5.9L
LDC
ENGINES

TO ATMOSPHERE
i
TRANSDUCER

FUEL
TANK

PRESSURE
RELIEF
ROLLOVER VALVE

W/ORIFICE

EVAP
CANISTER
TO CLIMATE CONTROL,
CRUISE
CONTROL,
4WD
AXLE

(WHEN
EQUIPPED) INTAKE
MANIFOLD
ORIFICE ENGINE
VALVE
COVER FUEL PRESSURE
REGULATOR
M

P
= MANIFOLD VACUUM
= PORTED VACUUM

"8^
EGR
VALVE
EVAP PURGE SOLENOID MAP

SENSOR

CHECK VALVE W/ORIFICE
CRANKCASE

BREATHER
TO
AIR
CLEANER
ENGINE VALVE
COVER TO BRAKE
BOOSTER FRONT
OF
VEHICLE
J9325-13

25
- 6
EMISSION CONTROL
SYSTEMS

•
EWAPORATIWE EMISSION CONTROLS

INDEX

page

Crankcase
Breather/Filter—Gas Powered
Engines
. . . 9

EVAP
(Evaporation)
Control
System
. 6

EVAP
Canister
. . 6
page

Evap
Canister
Purge
Solenoid
6

Fuel Tank
Filler
Tube
Cap . 7

Positive
Crankcase
Ventilation
(PCV)
System
.... 7

Pressure
Relief/Rollover Valve
6

EVAP (EVAPORATION) CONTROL SYSTEM GENERAL
INFORMATION
The function
of the
EVAP control system
is to
pre­
vent
the
emissions
of
gasoline vapors from
the
fuel
tank into
the
atmosphere. When fuel evaporates
in
the fuel tank,
the
vapors pass through vent hoses
or

tubes
to a
carbon filled EVAP canister. They
are

temporarily held
in the
canister until they
can be

drawn into
the
intake manifold when
the
engine
is

running.
The vapors
are
drawn into
the
engine
at
idle
as

well
as off
idle. This system
is
called
a
Bi-level Purge
System where there
is a
dual source
of
vacuum
to re­

move fuel vapor from
the
EVAP canister. The EVAP canister
is a
feature
on all
models
for

the storage
of
fuel vapors from
the
fuel tank.
The hoses used
in
this system
are
specially
manufactured.
If
replacement becomes neces­ sary,
it is
important
to use
only fuel resistant
hose.

PRESSURE
RELIEF/ROLLOVER VALVE
These vehicles
are
equipped with
a
combination
pressure relief
and
rollover valve. This dual function valve will relieve fuel tank pressure
and
also prevent
fuel flow through
the
fuel tank vent hoses
in the
event
of an
accidental vehicle rollover. The valve incorporates
a
pressure relief mechanism
that releases fuel tank pressure when
the
pressure increases above
the
calibrated sealing value. Refer
to

the Fuel Tank section
of
Group
14,
Fuel Systems
for

removal
and
installation procedures.

EVAP CANISTER
A sealed, maintenance free, EVAP canister
is
used
on
all
vehicles.
The
canister
is
mounted
in the en­
gine compartment
on the
right side wheel well
(Fig.
1).
The
EVAP canister
is
filled with granules
of an

activated carbon mixture. Fuel vapors entering
the

EVAP canister
are
absorbed
by the
charcoal gran­
ules.
Fuel tank pressure vents into
the
EVAP canister.
Fuel vapors
are
temporarily held
in the
canister
un­

til they
can be
drawn into
the
intake manifold.
The
EVAP canister purge solenoid allows
the
EVAP can­ ister
to be
purged
at
predetermined times
and at
cer­
tain engine operating conditions.
Refer
to the
Component Removal/Installation sec­
tion
of
this group
for
replacement procedures.

EVAPORATIVE
Fig.
1
EVAP
Canister Location

EVAP CANISTER PURGE SOLENOID
Vacuum
for the
EVAP canister
is
controlled
by the

EVAP canister purge solenoid
(Fig. 2). The
solenoid
is operated
by the
powertrain control module (PCM).
The
PCM
regulates
the
solenoid
by
switching
the

ground circuit
on and off
based
on
engine operating conditions. When energized,
the
solenoid prevents
vacuum from reaching
the
EVAP canister. When
not
energized,
the
solenoid allows vacuum
to
flow
through
to the
EVAP canister. During warm-up
and for a
specified time period
af­

ter
hot
starts,
the PCM
grounds
the
EVAP canister purge solenoid causing
it to
energize. This will pre­
vent vacuum from reaching
the
EVAP canister
valve. When
the
engine reaches
an
operating temper­ ature
of
approximately 27°C (80°F)
and a
time delay
interval
of
about
100
seconds
has
occurred,
the PCM

removes
the
ground
to
solenoid.
The
de-energized
so­
lenoid allows vacuum
to
flow
to the
EVAP canister and purge fuel vapors through
the
intake manifold. The EVAP canister purge solenoid will also
be en­

ergized during certain idle conditions
in
order
to up­

date
the
fuel delivery calibration. Refer
to the
Component Removal/Installation sec­
tion
of
this group
for
replacement procedures.

•

Fig.
2
EVAP
Canister
Purge
Solenoid—Typical

FUEL
TANK
FILLER
TUBE
CAP
The fuel tank is sealed with a pressure-vacuum re­
lief fuel tank filler tube cap (Fig. 3). The relief valves
in the cap are a safety feature. They operate only to
prevent excessive pressure or vacuum in tank caused
by a malfunction in system or damage to vent lines.

PLASTIC
GASKET

RN348

Fig.
3
Fuel
Tank
Filler
Tube Cap—Typical
The cap has a threaded configuration. This allows
the seal to be broken and pressure to be relieved without separation of cap from filler tube. Approxi­
mately two and a half turns are required to remove
the cap.
If replacement of filler tube cap is necessary, it
must be replaced with an identical cap to be sure of
correct system operation.

CAUTION:
Remove
the
fuel
tank
filler
tube cap to

relieve
any
fuel
tank
pressure.
The cap
must
be re­

moved
prior to
disconnecting
any
fuel
system
com­

ponent or before draining the
fuel
tank, •—-
EMISSION
CONTROL
SYSTEMS
25 - 7

Fig.
4 PCV Valve/Hose—Typical
A closed engine crankcase breather/filter, with a
hose connecting it to the air filter housing, provides
the source of air for system.
The PCV system operates by engine intake mani­
fold vacuum (Fig. 5). Filtered air is routed into the
crankcase through the air filter hose and crankcase
breather/filter. This forces crankcase vapors through
the PCV valve. It is then drawn into a passage in the intake manifold. Here it becomes part of the cali­
brated air/fuel mixture to be consumed in the com­ bustion chamber. The PCV system constantly ventilates the crankcase to help prevent sludge for­
mation and vapors from entering the atmosphere.
POSITIVE CRANKCASE VENTILATION (PCV) VALVE The PCV valve contains a spring loaded plunger.
This plunger meters the amount of crankcase vapors
routed into the combustion chamber based on intake
manifold vacuum.
When the engine is not operating or during an en­
gine popback, the spring forces the plunger back
against the seat. This will prevent vapors from flow­
ing through the valve (Fig. 6).
During periods of high manifold vacuum, such as
idle or cruising speeds, vacuum is sufficient to com­
pletely compress spring. It will then pull the plunger
to the top of the valve (Fig. 7). In this position there is minimal vapor flow through the valve.
POSITIVE
CRANKCASE
VENTILATION
(PCV)

SYSTEM

DESCRIPTION/OPERA
TION
All gas engines are equipped with a closed crank­
case ventilation system and PCV valve (Fig. 4).
This system consists of a crankcase PCV valve
mounted on the cylinder head (valve) cover with a
hose extending from the valve to the intake mani­ fold.

25-10
EMISSION
CONTROL
SYSTEMS

EXHAUST
EMISSION
CONTROLS

INDEX

page

Air Inlet—5.9L Diesel
Engine
13
Exhaust
Gas Recirculation (EGR)
Systems
10

HEATED
INLET
AIR
SYSTEM

The air filter housing mounted-heated inlet air sys­
tem is no longer used on any Dodge Truck gas pow­ ered engine.

EXHAUST
GAS
RECIRCULATION
(EGR)
SYSTEMS
GENERAL INFORMATION The EGR system reduces oxides of nitrogen (NOx)
in the engine exhaust and helps prevent spark
knock. This is accomplished by allowing a predeter­
mined amount of hot exhaust gas to recirculate and
dilute the incoming fuel/air mixture. This dilution
reduces peak flame temperature during combustion.
The system consists of an intake manifold mounted
EGR valve (Fig. 1) and connecting hoses. The vac­
uum to the EGR is controlled by the electric EGR
transducer (EET) (Figs. 1 and 2). The EET is a dual
electric/vacuum function switch. It is controlled by
engine vacuum and the powertrain control module (PCM).
Fig. 1 EGR System—Gas Powered Engines
EGR OPERATION The electric exhaust gas recirculation transducer
(EET) is a back pressure transducer and an electric
vacuum solenoid combined into a single unit (Figs. 1 and 2). The vacuum solenoid portion of the EET re­
ceives its electrical signal from the powertrain con­
trol module (PCM). Using this signal, the solenoid regulates the vacuum flowing through to the trans­ ducer portion of the EET. The back pressure trans-
page

Heated
Inlet
Air
System
. 10

Oxygen
(02)
Sensor
13

ELECTRICAL
VACUUM

CONNECTION
SUPPLY
9125-34

Fig.
2 Electric EGR Transducer
(EET)—Gas

Powered
Engines
ducer measures the amount of exhaust gas back
pressure on the exhaust side of the EGR valve. It
then varies the strength of the vacuum signal ap­
plied to the EGR valve. The transducer uses this
back pressure signal to provide the correct amount of exhaust gas recirculation under all conditions.
The vacuum supply for the EGR valve is controlled
by the EET. The electrical solenoid portion of the EET is controlled by the powertrain control module (PCM). The PCM monitors engine coolant tempera­
ture and other operating conditions to determine
when EGR operation is desired. Refer to Open Loop/ Closed Loop Modes of Operation in Group 14, Fuel
Systems for a description of EGR solenoid operation
based on engine operating conditions.
If the electrical connector to the EET is dis­
connected or the electrical signal is lost, the
EGR valve will operate at all times. This results
in poor engine performance and reduced driveability
during certain operating conditions.
Vacuum flows between the solenoid portion of the
EET and the transducer portion of the EET. This
happens only when the solenoid is not electrically en­ ergized. The transducer is connected to the EGR
valve by a vacuum hose and a back pressure hose.
The transducer is controlled by exhaust back pres­ sure and is ported to the exhaust manifold through a
hose connecting it to the bottom of the EGR valve.
Vacuum will be supplied to the EGR valve and
EGR operation will begin when:

•

EMISSION
CONTROL
SYSTEMS
25 - 11 • The electrical solenoid portion of the EET is not
energized.
• The engine back pressure entering the EGR valve
inlet is strong enough to close the transducer bleed
valve.
If back pressure is not strong enough to close the
transducer bleed valve, the transducer will bleed off the vacuum preventing EGR operation.
When the electrical solenoid portion of the EET is
de-energized by the powertrain control module (PCM), vacuum flows to the transducer. The trans­
ducer is connected to the engine exhaust system by a small hose that connects to the base of the EGR
valve.
The vacuum section of the transducer is controlled
by exhaust system back pressure. When back pres­ sure is high enough it will close a bleed valve in the
transducer allowing vacuum to actuate the EGR
valve. If back pressure does not close the bleed valve,
vacuum will be bled off.
For more information, refer to Group 14, Fuel Sys­

tems.
Refer to the Component Removal/Installation sec­
tion of this group for EGR valve replacement proce­
dures.

EGR SYSTEM ON-BOARD DIAGNOSTICS
(CALIFORNIA VEHICLES
ONLY)

The powertrain control module (PCM) performs an
On-Board Diagnostic (OBD) check of the EGR system
on all California vehicles. The diagnostic system uses
the electric EGR transducer (EET) for the system

tests.

The OBD check activates only during selected en­
gine/driving conditions. When the conditions are met,
the PCM energizes the EET solenoid to disable the EGR. The PCM checks for a change in the oxygen sensor signal. If the air-fuel mixture goes lean, the
PCM will attempt to enrichen the mixture. The PCM
registers a diagnostic trouble code (DTC) if the EGR system has failed or degraded. After registering a

DTC,
the PCM turns the malfunction indicator
lamp (MIL) on. (The malfunction indicator lamp was formerly referred to as the check engine lamp). The
malfunction indicator lamp indicates the need for im­
mediate service.
If a malfunction is indicated by the malfunction in­
dicator lamp and a DTC for the EGR system was set,
check for proper operation of EGR system. Use the
following: System Test, EGR Gas Flow Test and EGR
Diagnosis Chart.
If the EGR system tests properly, check the system
using the DRB II scan tool. For use of the DRB II,
refer to the appropriate Powertrain Diagnostics Pro­ cedure service manual. EGR SYSTEM SERVICE
A malfunctioning EGR system can cause engine
spark knock, sags or hesitation, rough idle, engine
stalling and poor driveability. To be sure of proper
operation of the EGR system, inspect all passages for
blockage. Check moving parts for binding. Inspect
the complete system for leaks. Replace system com­ ponents or hoses that are leaking.
Inspect all hose connections between throttle body,
intake manifold, EGR valve and EGR purge solenoid.
Replace any vacuum harness components that are
leaking or damaged. Refer to EGR Control System Test and EGR Gas
Flow Test to check EGR System operation.
EGR GAS FLOW TEST (1) Disconnect hose from EGR valve and connect a
hand vacuum pump to EGR valve nipple. Apply a
minimum of 12 inches vacuum the valve.
(2) The engine should now idle roughly or stall. If
this occurs, the valve is performing correctly. Proceed
to Electric EGR Transducer Test.
(3) If the engine idle speed did not change, remove
the EGR valve and inspect the valve and the exhaust passage in the manifold for blockage. Repair as nec­
essary. If blockage is not present, replace the EGR
valve.
ELECTRIC EGR TRANSDUCER (EET)

TESTING ELECTRIC SOLENOID PORTION OF TRANSDUCER
(1) Bring the engine to normal operating tempera­

ture.
Operate at idle speed. Test the EET as follows: (2) Check vacuum at EET vacuum source. Discon­
nect the hose and attach a vacuum gauge to it.
(3) Vacuum should be a minimum of 15 inches:
• If vacuum is low, check the line for kinks, twists
or a loose connection at vacuum connector or intake
manifold.
• If vacuum is correct, remove gauge. Connect the
vacuum line and proceed to next step. (4) Check EET operation using the appropriate
Powertrain Diagnostic Procedures service manual.
Refer to this manual for use of the DRB II scan tool and repair EET as necessary.

TESTING VACUUM PORTION
OF
TRANSDUCER
(1) Disconnect the EET vacuum lines, back pres­
sure line and electrical connector. Remove trans­
ducer.
(2) Plug the EET EGR valve port.
(3) Apply 1-2 pounds air pressure to exhaust back
pressure port. Air pressure can be supplied with a
hand operated air pump or compressed air (regulated
to correct psi).
(4) Apply a minimum of 12 inches of vacuum to
vacuum supply port.
Replace the EET if it will not hold vacuum.