1996 CHRYSLER VOYAGER engine

(2) Push locking tab on connector to unlock (Fig.
12).(3) Push down on connector latch and pull connec-
tor from pump.
(4) Remove hoses.
(5) Remove bolts holding LDP and bracket to cra-
dle.
(6) Remove bracket from LDP.
INSTALLATION
(1) Install LDP to bracket.
(2) Install LDP and bracket to cradle. Torque bolts
to 9.5-14 N´m (85-125 in. lbs.).Before installing
hoses to LDP, make sure they are not cracked
or split. If a hose leaks, it will cause the Check
Engine Lamp to illuminate.
(3) Install hoses to LDP.
(4) Plug electrical connector into LDP.
(5) Push connector locking tab into place.
(6) Using DRB scan tool, verify proper operation of
LDP.
ROLLOVER VALVES
All vehicles have 2 rollover valves on top of the
fuel tank. The valves prevent fuel flow through the
fuel tank vent valve hoses should the vehicle rollover.
The rollover valves on the fuel tank are not ser-
viceable.
Fig. 12 Leak Detection Pump Connector Lock
NSEMISSION CONTROL SYSTEMS 25 - 17
REMOVAL AND INSTALLATION (Continued)

EXHAUST GAS RECIRCULATION (EGR) SYSTEM
INDEX
page page
DESCRIPTION AND OPERATION
GENERAL INFORMATION................. 18
DIAGNOSIS AND TESTING
EGR GAS FLOW TEST................... 20
EGR SYSTEM ON-BOARD DIAGNOSTICS..... 19
EGR SYSTEM TEST..................... 19
EGR VALVE CONTROL (TRANSDUCER) TEST . 21
EGR VALVE LEAKAGE TEST............... 20REMOVAL AND INSTALLATION
EGR TUBE SERVICEÐ3.0L ENGINES........ 22
EGR TUBE SERVICEÐ3.3/3.8L ENGINES..... 22
EGR VALVE SERVICEÐ3.0L ENGINES....... 21
EGR VALVE SERVICEÐ3.3/3.8L ENGINES.... 22
SPECIAL TOOLS
EMISSION CONTROL SYSTEM............. 23
DESCRIPTION AND OPERATION
GENERAL INFORMATION
Refer to Monitored Systems - EGR Monitor in this
group for more information.
The 3.0, 3.3, and 3.8L engines use Exhaust Gas
Recirculation (EGR) systems (Fig. 1) and (Fig. 2).
The EGR system reduces oxides of nitrogen (NOx) in
engine exhaust and helps prevent spark knock. The
system allows a predetermined amount of hot
exhaust gas to recirculate and dilute the incoming
air/fuel mixture. The diluted air/fuel mixture reduces
peak flame temperature during combustion.
The EGR system consists of:
²EGR tube (connects a passage in the intake
manifold to the exhaust manifold)
²EGR valve
²Electronic EGR Transducer
²Connecting hoses
The Electronic EGR Transducer contains an elec-
trically operated solenoid and a back-pressure trans-ducer (Fig. 3). The PCM operates the solenoid. The
PCM determines when to energize the solenoid.
Exhaust system back-pressure controls the trans-
ducer.
When the PCM energizes the solenoid, vacuum
does not reach the transducer. Vacuum flows to the
transducer when the PCM de-energizes the solenoid.
When exhaust system back-pressure becomes high
enough, it fully closes a bleed valve in the trans-
ducer. When the PCM de-energizes the solenoid and
back-pressure closes the transducer bleed valve, vac-
uum flows through the transducer to operate the
EGR valve.
De-energizing the solenoid, but not fully closing the
transducer bleed hole (because of low back-pressure),
varies the strength of vacuum applied to the EGR
valve. Varying the strength of the vacuum changes
Fig. 1 EGR MountingÐ3.0L Engine
Fig. 2 EGR MountingÐ3.3/3.8L Engines
25 - 18 EMISSION CONTROL SYSTEMSNS

the amount of EGR supplied to the engine. This pro-
vides the correct amount of exhaust gas recirculation
for different operating conditions.
This system does not allow EGR at idle. The EGR
systems can operate at all coolant temperatures
above 60ÉF as long as the battery ambient tempera-
ture is above 7ÉF.
DIAGNOSIS AND TESTING
EGR SYSTEM ON-BOARD DIAGNOSTICS
The PCM performs an on-board diagnostic check of
the EGR system. The diagnostic system uses the
electronic EGR transducer for the system tests.
The diagnostic check activates only during selected
engine/driving conditions. When the conditions are
met, the PCM energizes the transducer solenoid to
disable the EGR. The PCM checks for a change in
the heated oxygen sensor signal. If the air-fuel mix-
ture goes lean, the PCM will attempt to enrichen the
mixture. The PCM registers a Diagnostic Trouble
Code (DTC) if the EGR system is not operating cor-
rectly. After registering a DTC, the PCM turns on the
malfunction indicator (Check Engine) lamp after 2
consecutive trips. There are 2 types of failures sensed
by the PCM. The first is a short or open in the elec-
trical solenoid circuit. The second is a mechanical
failure or loss of vacuum. The Malfunction Indicator
Lamp (MIL) indicates the need for service.
If a problem is indicated by the MIL and a DTC for
the EGR system is set, check for proper operation of
the EGR system. Use the System Test, EGR Gas
Flow Test. If the EGR system tests properly, check
the system using the DRB scan tool. Refer to
On-Board Diagnosis sections in this Group. Also,
refer to the DRB scan tool and the appropriate Pow-
ertrain Diagnostics Procedure manual.
EGR SYSTEM TEST
WARNING: APPLY PARKING BRAKE AND/OR
BLOCK WHEELS BEFORE TESTING THE EGR SYS-
TEM.
(1) Check the condition of all EGR system hoses
and tubes for leaks, cracks, kinks and hardening of
rubber hoses. Repair and correct these conditions
before performing any tests.
(2) Be sure the hoses at both the EGR valve and
EGR valve control are connected to the proper fit-
tings (Fig. 4).
(3) Be sure the electrical connector is firmly con-
nected at the valve control.
(4) To check EGR system operation, connect the
DRB scan tool to the 16±way data link connector.
The data link connector is located on the lower edge
of the instrument panel near the steering column.
Refer to the appropriate Powertrain Diagnostic Pro-
cedures service manual for operation of the DRB
scan tool when diagnosing the EGR system.
(5) After checking the system with the DRB scan
tool, proceed to the following EGR Valve Leakage and
EGR Valve Control Tests and repair as necessary.
Fig. 3 Electric EGR Transducer Assembly
Fig. 4 EGR Value and EGR Value ÐTypical
NSEMISSION CONTROL SYSTEMS 25 - 19
DESCRIPTION AND OPERATION (Continued)

EGR GAS FLOW TEST
Use the following test procedure to determine if
exhaust gas is flowing through the EGR valve. It can
also be used to determine if the EGR tube is plugged,
or the system passages in the intake or exhaust man-
ifolds are plugged.
This is not to be used as a complete test of the
EGR system.
The engine must be started, running and warmed
to operating temperature for this test.
(1) All engines are equipped with two fittings
located on the EGR valve (Fig. 5). The upper fitting
(located on the vacuum motor) supplies engine vac-
uum to a diaphragm within the EGR valve for valve
operation. The lower fitting (located on the base of
the EGR valve) is used to supply exhaust back-pres-
sure to the EGR valve control.
(2) Disconnect the rubber hose at the vacuum
motor fitting (Fig. 5) on the top of the EGR valve
vacuum motor.
(3) Connect a hand-held vacuum pump to this fit-
ting.
(4) Start the engine.
(5) Slowly apply 5 inches of vacuum to the fitting
on the EGR valve motor.
(6) While applying vacuum, a minimum of 3 inches
of vacuum, and with the engine running at idle
speed, the idle speed should drop or the engine may
even stall, if the vacuum is applied quickly. This is
indicating that exhaust gas is flowing through the
EGR tube between the intake and exhaust manifolds.(7) If the engine speed did not change, the EGR
valve may be defective, or EGR tube may be plugged
with carbon, or the passages in the intake and
exhaust manifolds may be plugged with carbon.
(a) Remove EGR valve from engine. Refer to
EGR Valve Removal in this group.
(b) Apply vacuum to the vacuum motor fitting
and observe the stem on the EGR valve. If the
stem is moving, it can be assumed that the EGR
valve is functioning correctly. The problem is in
either a plugged EGR tube or plugged passages at
the intake or exhaust manifolds, refer to step (c). If
the stem will not move, replace the EGR valve.
Note: The EGR valve, valve control and attaching
hoses are serviced as one unit. Refer to EGR Valve
Removal/Installation in this group.
(c) Remove the EGR tube between the intake
and exhaust manifolds. Check and clean the EGR
tube and its related openings on the manifolds.
Refer to EGR Tube in this group for procedures.
(8) Do not attempt to clean the EGR valve. If the
valve shows evidence of heavy carbon build-up near
the base, replace it.
EGR VALVE LEAKAGE TEST
This is not to be used as a complete test of the
EGR system.
If the engine will not idle, dies out on idle, or idle
is rough or slow, the poppet valve (Fig. 4) at the base
of the EGR valve may be leaking in the closed posi-
tion.
(1) The engine should be off for the following test.
(2) Disconnect the rubber hose from the fitting
(Fig. 4) at the top (vacuum motor) side of the EGR
valve.
(a) Connect a hand-held vacuum pump to this
fitting.
(b) Apply 15 inches of vacuum to the pump.
(c) Observe the gauge reading on the pump.
(d) If vacuum falls off, the diaphragm in the
EGR valve has ruptured.
(e) Replace the EGR valve. Note: The EGR
valve, valve control and attaching hoses are ser-
viced as one assembly. Refer to EGR Valve Remov-
al/Installation in this group.
(f) Proceed to the next step.
(3) A small metal fitting (back-pressure fitting) is
located at the base of the EGR valve (Fig. 4). A rub-
ber back-pressure hose connects it to the back-pres-
sure fitting on the EGR valve control. Disconnect this
rubber hose at the EGR valve fitting.
(4) Remove the air cleaner housing from the throt-
tle body.
(5) Using compressed air, and using an air nozzle
with a rubber tip, apply approximately 50 psi of reg-
Fig. 5 Typical EGR Valve
25 - 20 EMISSION CONTROL SYSTEMSNS
DIAGNOSIS AND TESTING (Continued)

ulated shop air to the metal back- pressure fitting on
the EGR valve.
(6) By hand, open the throttle to the wide open
position. AirSHOULD NOT BE HEARDemitting
from the intake manifold while applying air pressure
at the back-pressure fitting.
(7) If airCAN BE HEARDemitting from the
intake manifold, the poppet valve (Fig. 4) is leaking
at the bottom of the EGR valve. Replace the EGR
valve. Note: The EGR valve, valve control and
attaching hoses are serviced as one assembly. Refer
to EGR Valve Removal/Installation in this group. Do
not attempt clean the old EGR valve.
EGR VALVE CONTROL (TRANSDUCER) TEST
TESTING ELECTRICAL SOLENOID PORTION
OF VALVE
This is not to be used as a complete test of the
EGR system.
Electrical operation of the valve should be checked
with the DRB scan tool. Refer to the appropriate
Powertrain Diagnostic Procedures service manual for
operation of the DRB scan tool. Replace solenoid if
necessary, unit serviced only as an assembly.
TESTING VACUUM TRANSDUCER PORTION
OF VALVE
The first part of this test will determine if the
transducer diaphragm at the back-pressure side of
the valve has ruptured or is leaking. The second part
of the test will determine if engine vacuum (full-man-
ifold) is flowing from the inlet to the outlet side of
the valve. This is not to be used as a complete test of
the EGR system.
(1) Disconnect the rubber back-pressure hose from
the fitting at the bottom of EGR valve (Fig. 4).
(2) Connect a hand-held vacuum pump to this fit-
ting.
(3) Apply 10 inches of vacuum to this fitting.
(4) If vacuum falls off, the valve diaphragm is
leaking.
(5) Replace the EGR valve assembly. Proceed to
next step for further testing.
(6) Remove the rubber hose at the vacuuminlet
fitting (Fig. 4) on the EGR valve.
(7) Connect a vacuum gauge to this disconnected
hose.
(8) Start the engine and bring to operating tem-
perature. Hold engine speed at approximately 1500
rpm.
(9) Check for steady engine vacuum (full-manifold)
at this hose.
(10) If engine vacuum (full-manifold) is not
present, check vacuum line to engine and repair as
necessary before proceeding to next step.(11) Reconnect the rubber hose to the vacuum
inletfitting (Fig. 4) on the EGR valve.
(12) Disconnect the rubber hose at the vacuum
outletfitting (Fig. 4) on the EGR valve.
(13) Connect a vacuum gauge to this fitting.
(14) Disconnect the electrical connector (Fig. 4) at
the valve control. This will simulate an open circuit
(no ground from the PCM) at the valve.
(15) Start the engine and bring to operating tem-
perature.
(16) Hold the engine speed to approximately 2000
rpm while checking for engine vacuum (full-manifold)
at this fitting.To allow full manifold vacuum to
flow through the valve, exhaust back-pressure
must be present at valve. It must be high
enough to hold the bleed valve in the trans-
ducer portion of the valve closed.Have a helper
momentarily (a second or two) hold a rag over the
tailpipe opening to build some exhaust back-pressure
while observing the vacuum gauge. Heavy gloves
should be worn.Do not cover the tailpipe open-
ing for an extended period of time as damage to
components or overheating may result.
(17) As temporary back-pressure is built, full man-
ifold vacuum should be observed at the vacuum out-
let fitting. Without back-pressure, and engine at
approximately 2000 rpm, the gauge reading will be
low. This low reading is normal. At idle speed, the
gauge reading will be erratic. This is also normal.
(18) If full manifold vacuum is not present at the
outlet fitting, but was present at the inlet fitting,
replace the valve. Note: The EGR valve, valve control
and attaching hoses are serviced as one assembly.
Refer to EGR Valve Removal/Installation in this
group.
REMOVAL AND INSTALLATION
EGR VALVE SERVICEÐ3.0L ENGINES
The EGR valve and Electrical EGR Transducer are
serviced as an assembly.
REMOVAL
(1) Disconnect the electric and vacuum connectors
from the electric EGR transducer (Fig. 6).
(2) Remove EGR valve mounting bolts.
(3) Clean all gasket surfaces and discard old gas-
kets. Check for any signs of leakage or cracked sur-
faces. Repair or replace as necessary.
INSTALLATION
(1) Install EGR valve and new gasket on intake
manifold. Tighten mounting bolts to 22 N´m (200 in.
lbs.) torque.
(2) Connect the electrical and vacuum connectors
to the electric EGR transducer.
NSEMISSION CONTROL SYSTEMS 25 - 21
DIAGNOSIS AND TESTING (Continued)

EGR VALVE SERVICEÐ3.3/3.8L ENGINES
The EGR valve and Electrical EGR Transducer are
serviced as an assembly.
REMOVAL
(1) Disconnect vacuum tube from electric EGR
transducer. Inspect vacuum tube for damage (Fig. 7).
(2) Remove electrical connector from solenoid.
(3) Remove EGR valve bolts from intake manifold.
(4) Open EGR transducer clip and remove electric
EGR transducer.
(5) Remove EGR valve from intake manifold.
(6) Clean gasket surface and discard old gasket.
Check for any signs of leakage or cracked surfaces.
Repair or replace as necessary.
INSTALLATION
(1) Assemble EGR valve with new gasket onto the
intake manifold.
(2) Install mounting bolts. Tighten bolts to 22 N´m
(200 in. lbs.) torque.
(3) Install electric EGR transducer in clip with ori-
entation tab in slot and snap closed.
(4) Reconnect vacuum hose and electrical connec-
tor to electrical EGR transducer.
EGR TUBE SERVICEÐ3.0L ENGINES
REMOVAL
(1) Remove EGR tube flange nuts from exhaust
manifold (Fig. 6).
(2) Remove EGR valve nuts at intake manifold.
Remove EGR tube.(3) Clean all gasket surfaces and discard old gas-
kets. Check for any signs of leakage or cracked sur-
faces. Repair or replace as necessary.
INSTALLATION
(1) Loosely install the EGR tube on the intake and
exhaust manifolds with new gaskets.
(2) Tighten EGR tube flange bolts at the intake
manifold to 22 N´m (200 in. lbs.) torque.
(3) Tighten EGR tube to exhaust manifold nuts to
22 N´m (200 in. lbs.) torque.
EGR TUBE SERVICEÐ3.3/3.8L ENGINES
REMOVAL
(1) Remove EGR tube attaching bolts from intake
and exhaust manifolds (Fig. 8).
(2) Clean intake and exhaust manifold gasket sur-
faces. Discard old gasket.
(3) Check for signs of leakage or cracked surfaces
on either manifolds or tube. Repair or replace as nec-
essary.
Fig. 6 EGR System ServiceÐ3.0L EnginesFig. 7 EGR SystemÐ3.3/3.8L Engines
25 - 22 EMISSION CONTROL SYSTEMSNS
REMOVAL AND INSTALLATION (Continued)

EMISSION CONTROL SYSTEM
CONTENTS
page page
EMISSION CONTROL SYSTEMÐ
2.0L ENGINE.......................... 9
EXHAUST EMISSION CONTROLSÐ
2.5L DIESEL ENGINE................... 5ON-BOARD DIAGNOSTICSÐ
2.5L DIESEL ENGINE................... 1
ON-BOARD DIAGNOSTICSÐ2.5L DIESEL ENGINE
INDEX
page page
GENERAL INFORMATION
SYSTEM DESCRIPTIONÐ
2.5L DIESEL ENGINE................... 1DESCRIPTION AND OPERATION
DIAGNOSTIC TROUBLE CODES............ 2
GENERAL INFORMATION
SYSTEM DESCRIPTIONÐ2.5L DIESEL ENGINE
The 2.5L diesel Powertrain Control Module (PCM)
monitors and controls many different circuits in the
fuel injection pump and engine systems. If the PCM
senses a problem with a monitored circuit that indi-
cates an actual problem, a Diagnostic Trouble Code
(DTC) will be stored in the PCM's memory, and even-
tually will illuminate the Diesel Glow Plug lamp con-
stantly while the key is on. If the problem is
repaired, or is intermittent, the PCM will erase the
DTC after 40 warm-up cycles. A warm-up cycle con-
sists of starting the vehicle when the engine is cold,
then the engine to warms up to a certain tempera-
ture, and finally, the engine temperature falls to a
normal operating temperature, then the key is
turned off.
Certain criteria must be met for a DTC to be
entered into PCM memory. The criteria may be a
specific range of engine rpm, engine or fuel tempera-
ture and/or input voltage to the PCM. A DTC indi-
cates that the PCM has identified an abnormal
signal in a circuit or the system. A DTC may indicate
the result of a failure, but never identify the failed
component directly.
There are several operating conditions that the
PCM does not monitor and set a DTC for. Refer to
the following Monitored Circuits and Non±Monitored
Circuits in this section.
MONITORED CIRCUITS
The PCM can detect certain problems in the elec-
trical system.
Open or Shorted Circuit± The PCM can deter-
mine if sensor output (which is the input to PCM) is
within proper range. It also determines if the circuit
is open or shorted.
Output Device Current Flow± The PCM senses
whether the output devices are electrically connected.
If there is a problem with the circuit, the PCM
senses whether the circuit is open, shorted to ground
(±), or shorted to (+) voltage.
NON±MONITORED CIRCUITS
The PCM does not monitor the following circuits,
systems or conditions that could have malfunctions
that result in driveability problems. A DTC will not
be displayed for these conditions.
Fuel Pressure:Fuel pressure is controlled by the
fuel injection pump. The PCM cannot detect prob-
lems in this component.
Cylinder Compression:The PCM cannot detect
uneven, low, or high engine cylinder compression.
Exhaust System:The PCM cannot detect a
plugged, restricted or leaking exhaust system.
Fuel Injector Malfunctions:The PCM cannot
determine if the fuel injector is clogged, or the wrong
injector is installed. The fuel injectors on the diesel
engine arenot controlledby the PCM, although a
NS/GSEMISSION CONTROL SYSTEM 25 - 1

defective fuel injector sensoris monitoredby the
PCM.
Vacuum Assist:Leaks or restrictions in the vac-
uum circuits of vacuum assisted engine control sys-
tem devices are not monitored by the PCM.
PCM System Ground:The PCM cannot deter-
mine a poor system ground. However, a DTC may be
generated as a result of this condition.
PCM Connector Engagement:The PCM cannot
determine spread or damaged connector pins. How-
ever, a DTC may be generated as a result of this con-
dition.
HIGH AND LOW LIMITS
The PCM compares input signal voltages from each
input device. It will establish high and low limits
that are programmed into it for that device. If the
input voltage is not within specifications and other
DTC criteria are met, a DTC will be stored in mem-
ory. Other DTC criteria might include engine rpm
limits or input voltages from other sensors or
switches. The other inputs might have to be sensed
by the PCM when it senses a high or low input volt-
age from the control system device in question.
DESCRIPTION AND OPERATION
DIAGNOSTIC TROUBLE CODES
On the following pages, a list of DTC's is provided
for the 2.5L diesel engine. A DTC indicates that the
PCM has recognized an abnormal signal in a circuitor the system. A DTC may indicate the result of a
failure, but most likely will not identify the failed
component directly.
ACCESSING DIAGNOSTIC TROUBLE CODES
A stored DTC can be displayed through the use of
the DRB III scan tool. The DRB III connects to the
data link connector. The data link connector is
located under the instrument panel near bottom of
the steering column (Fig. 1).
ERASING TROUBLE CODES
After the problem has been repaired, use the DRB
III scan tool to erase a DTC.
Generic Scan
Tool CodeDRB III Scan Tool Display
P1112 Boost Pressure Sensor Signal High
Boost Pressure Sensor Signal Low
Boost Pressure Sensor Supply High
Boost Pressure Sensor Supply Low
Boost Pressure Sensor Plausibility
P0110 Intake Air Temperature Sensor Signal High
Intake Air Temperature Sensor Signal Low
P1685 Immobilizer Signal Lost
Invalid SKIM Message
P0115 Temperature of Engine Coolant SRC High Exceeded
Temperature of Engine Coolant SRC Low Exceeded
P0180 Fuel Temperature Sensor SRC High Exceeded
Fuel Temperature Sensor SRC Low Exceeded
P0400 EGR Open Circuit
EGR Short Circuit
P0500 Vehicle Speed Sensor PEC Frequency Too High
Vehicle Speed Sensor Signal SRC High Exceeded
Fig. 1 Data Link Connector LocationÐTypical
25 - 2 EMISSION CONTROL SYSTEMNS/GS
GENERAL INFORMATION (Continued)