Vacuum line DODGE RAM 1500 1998 2.G Service Manual

DIAGNOSIS AND TESTING - REFRIGERANT
SYSTEM LEAKS
WARNING: R-134a SERVICE EQUIPMENT OR VEHI-
CLE A/C SYSTEM SHOULD NOT BE PRESSURE
TESTED OR LEAK TESTED WITH COMPRESSED
AIR. MIXTURE OF AIR and R-134a CAN BE COM-
BUSTIBLE AT ELEVATED PRESSURES. THESE MIX-
TURES ARE POTENTIALLY DANGEROUS AND MAY
RESULT IN FIRE OR EXPLOSION CAUSING INJURY
OR PROPERTY DAMAGE.
AVOID BREATHING A/C REFRIGERANT AND LUBRI-
CANT VAPOR OR MIST. EXPOSURE MAY IRRITATE
EYES, NOSE AND THROAT. USE ONLY APPROVED
SERVICE EQUIPMENT MEETING SAE REQUIRE-
MENTS TO DISCHARGE R-134a SYSTEM. IF ACCI-
DENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
NOTE: The refrigerant system does come from the
factory with a yellow tracer dye already installed to
aid in detection of leaks.
If the A/C system is not cooling properly, determine
if the refrigerant system is fully charged with
R-134a. This is accomplished by performing a system
Charge Level-Check or Fill. If while performing this
test A/C liquid line pressure is less than 345 kPa (50
psi) proceed to System Empty procedure. If liquid
line pressure is greater than 345 kPa (50 psi) proceed
to System Low procedure. If the refrigerant system is
empty or low in refrigerant charge, a leak at any line
fitting or component seal is likely. A review of the fit-
tings, lines and components for oily residue is an
indication of the leak location. To detect a leak in the
refrigerant system, perform one of the following pro-
cedures as indicated by the symptoms.
SYSTEM EMPTY
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible (approx. 28 in Hg.). Deter-
mine if the system holds a vacuum for 15 minutes. If
vacuum is held, a leak is probably not present. If sys-
tem will not maintain vacuum level, proceed with
this procedure.(2) Prepare a 0.284 Kg. (10 oz.) refrigerant charge
to be injected into the system.
(3) Connect and dispense 0.284 Kg. (10 oz.) of
refrigerant into the evacuated refrigerant system.
(4) Proceed to Step 2 of System Low procedure.
SYSTEM LOW
(1) Determine if there is any (R-134a) refrigerant
in the system.
(2) Position the vehicle in a wind free work area.
This will aid in detecting small leaks.
(3) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run for five minutes with the system
set to the following:
²Transmission in Park or Neutral with parking
brake set
²Engine idling at 700 rpm
²A/C controls set in 100 percent outside air
²Blower switch in the high A/C position
²A/C in the ON position
²Open all windows
CAUTION: A leak detector designed for R-12 refrig-
erant (only) will not detect leaks in a R-134a refrig-
erant system.
(4) Shut off the vehicle and wait 2 to 7 minutes.
Then use an Electronic Leak Detector that is
designed to detect R-134a type refrigerant and search
for leaks. Fittings, lines, or components that appear
to be oily usually indicates a refrigerant leak. To
inspect the evaporator core for leaks, insert the leak
detector probe into the drain tube opening or a heat
duct. A R-134a dye is available to aid in leak detec-
tion, use only DaimlerChrysler approved refrigerant
dye.
24 - 44 PLUMBINGDR
PLUMBING (Continued)

STANDARD PROCEDURE - REFRIGERANT
SYSTEM SERVICE EQUIPMENT
WARNING: EYE PROTECTION MUST BE WORN
WHEN SERVICING AN AIR CONDITIONING REFRIG-
ERANT SYSTEM. TURN OFF (ROTATE CLOCKWISE)
ALL VALVES ON THE EQUIPMENT BEING USED
BEFORE CONNECTING TO, OR DISCONNECTING
FROM THE REFRIGERANT SYSTEM. FAILURE TO
OBSERVE THESE WARNINGS MAY RESULT IN PER-
SONAL INJURY.
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) and (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
When servicing the air conditioning system, a
R-134a refrigerant recovery/recycling/charging sta-
tion that meets SAE Standard J2210 must be used
(Fig. 2). Contact an automotive service equipment
supplier for refrigerant recovery/recycling/charging
equipment. Refer to the operating instructions sup-
plied by the equipment manufacturer for proper care
and use of this equipment.
A manifold gauge set may be needed with some
recovery/recycling/charging equipment (Fig. 3). The
service hoses on the gauge set being used should
have manual (turn wheel), or automatic back-flow
valves at the service port connector ends. This will
prevent refrigerant from being released into the
atmosphere.
MANIFOLD GAUGE SET CONNECTIONS
CAUTION: Do not use an R-12 manifold gauge set
on an R-134a system. The refrigerants are not com-
patible and system damage will result.
LOW PRESSURE GAUGE HOSE The low pressure
hose (Blue with Black stripe) attaches to the low side
service port. This service port is located on the suc-
tion line between the accumulator outlet port and the
A/C compressor.
HIGH PRESSURE GAUGE HOSE The high pres-
sure hose (Red with Black stripe) attaches to the
high side service port. This service port is located on
the discharge line near the A/C compressor. On this
model, an A/C pressure transducer is installed onto
the high pressure service port. A/C high side pres-
sures can be read using a DRBIIItscan tool. Refer to
Body Diagnostic Procedures.
RECOVERY/RECYCLING/EVACUATION/CHARG-
ING HOSE The center manifold hose (Yellow, or
White, with Black stripe) is used to recover, evacu-
ate, and charge the refrigerant system. When the low
or high pressure valves on the manifold gauge set
are opened, the refrigerant in the system will escape
through this hose.
Fig. 2 Refrigerant Recovery/Recycling Station -
Typical
1 - R-134a REFRIGERANT STATION
Fig. 3 MANIFOLD GAUGE SET - TYPICAL
1 - HIGH PRESSURE GAUGE
2 - VALVE
3 - VACUUM/REFRIGERANT HOSE (YELLOW W/ BLACK STRIPE)
4 - HIGH PRESSURE HOSE (RED W/ BLACK STRIPE)
5 - LOW PRESSURE HOSE (BLUE W/ BLACK STRIPE)
6 - VALVE
7 - LOW PRESSURE GAUGE
24 - 46 PLUMBINGDR
PLUMBING (Continued)

STANDARD PROCEDURE - REFRIGERANT
RECOVERY
WARNING: REVIEW THE WARNINGS AND CAU-
TIONS IN THE FRONT OF THIS SECTION BEFORE
PERFORMING THE FOLLOWING OPERATION (Refer
to 24 - HEATING & AIR CONDITIONING/PLUMBING -
WARNING) and (Refer to 24 - HEATING & AIR CON-
DITIONING/PLUMBING - CAUTION).
A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to recover the refrigerant from an R-134a refrig-
erant system. Refer to the operating instructions sup-
plied by the equipment manufacturer for the proper
care and use of this equipment.
STANDARD PROCEDURE - REFRIGERANT
SYSTEM EVACUATE
NOTE: Special effort must be used to prevent mois-
ture from entering the A/C system oil. Moisture in
the oil is very difficult to remove and will cause a
reliability problem with the compressor.
If a compressor designed to use R-134a refrigerant
is left open to the atmosphere for an extended period
of time. It is recommended that the refrigerant oil be
drained and replaced with new oil or a new compres-
sor be used. This will eliminate the possibility of con-
taminating the refrigerant system.
If the refrigerant system has been open to the
atmosphere, it must be evacuated before the system
can be filled. Moisture and air mixed with the refrig-
erant will raise the compressor head pressure above
acceptable operating levels. This will reduce the per-
formance of the air conditioner and damage the com-
pressor. Moisture will boil at near room temperature
when exposed to vacuum. To evacuate the refrigerant
system:
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Recover the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
(2) Connect a suitable charging station, refrigerant
recovery machine or a manifold gauge set with vac-
uum pump and refrigerant recovery equipment.
(3) Open the suction and discharge valves and
start the vacuum pump. The vacuum pump should
run a minimum of 45 minutes prior to charge to
eliminate all moisture in system. When the suction
gauge reads -88 kPa (- 26 in. Hg) vacuum or greaterfor 30 minutes, close all valves and turn off vacuum
pump. If the system fails to reach specified vacuum,
the refrigerant system likely has a leak that must be
corrected. If the refrigerant system maintains speci-
fied vacuum for at least 30 minutes, start the vac-
uum pump, open the suction and discharge valves.
Then allow the system to evacuate an additional 10
minutes.
(4) Close all valves. Turn off and disconnect the
vacuum pump.
(5) Charge the refrigerant system (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
STANDARD PROCEDURE).
STANDARD PROCEDURE - REFRIGERANT
SYSTEM CHARGE
WARNING: REVIEW SAFETY PRECAUTIONS AND
WARNINGS IN THIS GROUP BEFORE CHARGING
THE REFRIGERANT SYSTEM.
AVOID BREATHING A/C REFRIGERANT AND LUBRI-
CANT VAPOR OR MIST. EXPOSURE MAY IRRITATE
EYES, NOSE AND THROAT. USE ONLY APPROVED
SERVICE EQUIPMENT MEETING SAE REQUIRE-
MENTS TO DISCHARGE R-134a SYSTEM. IF ACCI-
DENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
R-134a SERVICE EQUIPMENT OR VEHICLE A/C
SYSTEM SHOULD NOT BE PRESSURE TESTED OR
LEAK TESTED WITH COMPRESSED AIR. MIXTURE
OF AIR and R-134a CAN BE COMBUSTIBLE AT ELE-
VATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP-
ERTY DAMAGE.
CAUTION: Do not overcharge refrigerant system, as
excessive compressor head pressure can cause
noise and system failure.
CAUTION: A small amount of refrigerant oil is
removed from the A/C system each time the refrig-
erant system is recovered and evacuated. Before
charging the A/C system, you MUST replenish any
oil lost during the recovery process. Refer the
equipment manufacturer instructions for more infor-
mation.
The procedure below should be used to fill the
refrigerant charge in the air conditioning system.
This A/C system does not have or use a sight glass to
check or charge the system.
DRPLUMBING 24 - 47
PLUMBING (Continued)

After the system has been tested for leaks and
evacuated, a refrigerant (R-134a) charge can be
injected into the system.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) If using a separate vacuum pump close all
valves before disconnecting pump. Connect manifold
gauge set to the A/C service ports.
NOTE: Always refer to the underhood HVAC Speci-
fication label for the refrigerant fill level of the vehi-
cle being serviced.
(2) Measure refrigerant (refer to capacities). Refer
to the instructions provided with the equipment
being used.
(3) Verify engine is shut off. Open the suction and
discharge valves. Open the charge valve to allow the
refrigerant to flow into the system. When the trans-
fer of refrigerant has stopped, close the suction and
discharge valve.
(4) If all of the charge did not transfer from the
dispensing device, put vehicle controls into the fol-
lowing mode:
²Automatic transmission in park or manual
transmission in neutral
²Engine at idle
²A/C mode control set to outside air
²A/C mode control set to panel mode
²A/C temperature control set to full cool
²Blower motor control set on highest speed
²Vehicle windows closed
If the A/C compressor does not engage, test the
compressor clutch control circuit and correct any fail-
ure (Refer to 8 - ELECTRICAL/WIRING DIAGRAM
INFORMATION - DIAGNOSIS AND TESTING).
(5) Open the suction valve to allow the remaining
refrigerant to transfer to the system.
WARNING: TAKE CARE NOT TO OPEN THE DIS-
CHARGE (HIGH-PRESSURE) VALVE AT THIS TIME.
(6) Close all valves and test the A/C system perfor-
mance.
(7) Disconnect the charging station or manifold
gauge set. Install the service port caps.
REFRIGERANT CHARGE CAPACITY
The R-134a refrigerant system charge capacity for
this vehicle can be found on the underhood HVAC
specfication tag.
A/C COMPRESSOR
DESCRIPTION
DESCRIPTION - A/C COMPRESSOR
The A/C system on models equipped with the 5.9L
engine use a Sanden SD-7 reciprocating swash plate-
type compressor. This compressor has a fixed dis-
placement of 165 cubic centimeter (10.068 cubic
inches) and has both the suction and discharge ports
located on the cylinder head.
The A/C system on models equipped with the 3.7L,
4.7L and 5.7L engines use a Denso 10S17 reciprocat-
ing swash plate-type compressor. This compressor
has a fixed displacement of 170 cubic centimeter and
has both the suction and discharge ports located on
the cylinder head.
A label identifying the use of R-134a refrigerant is
located on both A/C compressors.
DESCRIPTION - HIGH PRESSURE RELIEF
VALVE
A high pressure relief valve is located on the com-
pressor cylinder head, which is on the rear of the
compressor. This mechanical valve is designed to
vent refrigerant from the system to protect against
damage to the compressor and other system compo-
nents, caused by condenser air flow restriction or an
overcharge of refrigerant.
OPERATION
OPERATION - A/C COMPRESSOR
The A/C compressor is driven by the engine
through an electric clutch, drive pulley and belt
arrangement. The compressor is lubricated by refrig-
erant oil that is circulated throughout the refrigerant
system with the refrigerant.
The compressor draws in low-pressure refrigerant
vapor from the evaporator through its suction port. It
then compresses the refrigerant into a high-pressure,
high-temperature refrigerant vapor, which is then
pumped to the condenser through the compressor dis-
charge port.
The compressor cannot be repaired. If faulty or
damaged, the entire compressor assembly must be
replaced. The compressor clutch, pulley and clutch
coil are available for service.
OPERATION - HIGH PRESSURE RELIEF VALVE
The high pressure relief valve vents the system
when a discharge pressure of 3445 to 4135 kPa (500
to 600 psi) or above is reached. The valve closes
24 - 48 PLUMBINGDR
PLUMBING (Continued)

EVAPORATIVE EMISSIONS
TABLE OF CONTENTS
page page
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAP SYSTEM............10
SPECIFICATIONS
TORQUE - EVAP SYSTEM...............11
CCV HOSE
DESCRIPTION - 8.0L V-10................12
OPERATION - 8.0L V-10..................12
EVAP/PURGE SOLENOID
DESCRIPTION.........................12
OPERATION...........................12
REMOVAL.............................12
INSTALLATION.........................12
FUEL FILLER CAP
DESCRIPTION.........................13
OPERATION...........................13
REMOVAL
REMOVAL/INSTALLATION...............13
LEAK DETECTION PUMP
DESCRIPTION.........................13
OPERATION...........................14
REMOVAL.............................16
INSTALLATION.........................16ORVR
DESCRIPTION.........................17
OPERATION...........................17
P C V VA LV E
DESCRIPTION.........................17
OPERATION...........................19
DIAGNOSIS AND TESTING - PCV VALVE -
3.7L V-6/ 4.7L V-8......................20
REMOVAL.............................21
INSTALLATION.........................21
VACUUM LINES
DESCRIPTION.........................22
VAPOR CANISTER
DESCRIPTION.........................22
OPERATION...........................22
REMOVAL.............................22
INSTALLATION.........................22
NATURAL VAC LEAK DETECTION ASSY
DESCRIPTION.........................23
OPERATION...........................23
REMOVAL.............................24
INSTALLATION.........................25
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAP SYSTEM
The evaporation control system prevents the emis-
sion of fuel tank vapors into the atmosphere. When
fuel evaporates in the fuel tank, the vapors pass
through vent hoses or tubes into the two charcoal
filled evaporative canisters. The canisters tempo-
rarily hold the vapors. The Powertrain Control Mod-
ule (PCM) allows intake manifold vacuum to draw
vapors into the combustion chambers during certain
operating conditions.
All gasoline powered engines use a duty cycle
purge system. The PCM controls vapor flow by oper-
ating the duty cycle EVAP purge solenoid. Refer to
Duty Cycle EVAP Canister Purge Solenoid for addi-
tional information.When equipped with certain emissions packages, a
Leak Detection Pump (LDP) will be used as part of
the evaporative system. This pump is used as a part
of OBD II requirements. Refer to Leak Detection
Pump for additional information. Other emissions
packages will use a Natural Vacuum Leak Detection
(NVLD) system in place of the LDP. Refer to NVLD
for additional information.
NOTE: The hoses used in this system are specially
manufactured. If replacement becomes necessary, it
is important to use only fuel resistant hose.
Certain EVAP system components can be found in
(Fig. 1).
25 - 10 EVAPORATIVE EMISSIONSDR

PUMPING ACTION
Action : During portions of this test, the PCM uses
the reed switch to monitor diaphragm movement.
The solenoid is only turned on by the PCM after the
reed switch changes from open to closed, indicating
that the diaphragm has moved down. At other times
during the test, the PCM will rapidly cycle the LDP
solenoid on and off to quickly pressurize the system.
During rapid cycling, the diaphragm will not move
enough to change the reed switch state. In the state
of rapid cycling, the PCM will use a fixed time inter-
val to cycle the solenoid. If the system does not pass
the EVAP Leak Detection Test, the following DTCs
may be set:
²P0442 - EVAP LEAK MONITOR 0.0409LEAK
DETECTED
²P0455 - EVAP LEAK MONITOR LARGE LEAK
DETECTED
²P0456 - EVAP LEAK MONITOR 0.0209LEAK
DETECTED
²P1486 - EVAP LEAK MON PINCHED HOSE
FOUND
²P1494 - LEAK DETECTION PUMP SW OR
MECH FAULT
²P1495 - LEAK DETECTION PUMP SOLENOID
CIRCUIT
REMOVAL
The Leak Detection Pump (LDP) and LDP filter
are attached to the front of the EVAP canister
mounting bracket (Fig. 9). This is located near the
front of the fuel tank. The LDP and LDP filter are
replaced (serviced) as one unit.
(1) Raise and support vehicle.
(2) Carefully remove hose at LDP filter.
(3) Remove LDP filter mounting bolt and remove
from vehicle.
(4) Carefully remove vapor/vacuum lines at LDP.
(5) Disconnect electrical connector at LDP.
(6) Remove LDP mounting bolt and remove LDP
from vehicle.
INSTALLATION
The LDP and LDP filter are attached to the front
of the EVAP canister mounting bracket. The LDP
and LDP filter are replaced (serviced) as one unit.
(1) Install LDP to mounting bracket. Refer to
Torque Specifications.
(2) Install LDP filter to mounting bracket. Refer to
Torque Specifications.
(3) Carefully install vapor/vacuum lines to LDP,
and install hose to LDP filter.The vapor/vacuum
lines and hoses must be firmly connected.
Fig. 8 DIAPHRAGM DOWNWARD MOVEMENT
1 - Diaphragm
2 - Inlet Check Valve (Closed)
3 - Vent Valve (Closed)
4 - From Air Filter
5 - To Canister
6 - Outlet Check Valve (Open)
7 - Engine Vacuum (Closed)
Fig. 9 LDP AND LDP FILTER LOCATION
1 - LDP
2 - LDP MOUNTING BOLT
3 - ELEC. CONNEC.
4 - FILTER MOUNTING BOLT
5 - LDP FILTER
6 - CONNECTING HOSE
7 - EVAP CANISTER MOUNTING BRACKET
8 - EVAP CANISTERS (2)
25 - 16 EVAPORATIVE EMISSIONSDR
LEAK DETECTION PUMP (Continued)

Check the vapor/vacuum lines at the LDP, LDP
filter and EVAP canister purge solenoid for
damage or leaks. If a leak is present, a Diagnos-
tic Trouble Code (DTC) may be set.
(4) Connect electrical connector to LDP.
ORVR
DESCRIPTION
The ORVR (On-Board Refueling Vapor Recovery)
system consists of a unique fuel tank, flow manage-
ment valve, fluid control valve, one-way check valve
and vapor canister.
OPERATION
The ORVR (On-Board Refueling Vapor Recovery)
system is used to remove excess fuel tank vapors.
This is done while the vehicle is being refueled.
Fuel flowing into the fuel filler tube (approx. 1º
I.D.) creates an aspiration effect drawing air into the
fuel fill tube. During refueling, the fuel tank is
vented to the EVAP canister to capture escaping
vapors. With air flowing into the filler tube, there are
no fuel vapors escaping to the atmosphere. Once the
refueling vapors are captured by the EVAP canister,
the vehicle's computer controlled purge system draws
vapor out of the canister for the engine to burn. The
vapor flow is metered by the purge solenoid so that
there is no, or minimal impact on driveability or
tailpipe emissions.
As fuel starts to flow through the fuel fill tube, it
opens the normally closed check valve and enters the
fuel tank. Vapor or air is expelled from the tank
through the control valve and on to the vapor canis-
ter. Vapor is absorbed in the EVAP canister until
vapor flow in the lines stops. This stoppage occurs
following fuel shut-off, or by having the fuel level in
the tank rise high enough to close the control valve.
This control valve contains a float that rises to seal
the large diameter vent path to the EVAP canister.
At this point in the refueling process, fuel tank pres-
sure increases, the check valve closes (preventing liq-
uid fuel from spiting back at the operator), and fuel
then rises up the fuel filler tube to shut off the dis-
pensing nozzle.
PCV VALVE
DESCRIPTION
3.7L V-6 / 4.7L V-8
The 3.7L V-6 and 4.7L V-8 engines are equipped
with a closed crankcase ventilation system and a
Positive Crankcase Ventilation (PCV) valve.
This system consists of:
²a PCV valve mounted to the oil filler housing
(Fig. 10). The PCV valve is sealed to the oil filler
housing with an o-ring.
²the air cleaner housing
²two interconnected breathers threaded into the
rear of each cylinder head (Fig. 11).
²tubes and hoses to connect the system compo-
nents.
Fig. 10 PCV VALVE - 3.7L V-6 / 4.7L V-8
1 - O-RING
2 - LOCATING TABS
3 - CAM LOCK
4 - OIL FILLER TUBE
5 - PCV LINE/HOSE
6 - P C V VA LV E
DREVAPORATIVE EMISSIONS 25 - 17
LEAK DETECTION PUMP (Continued)

DIAGNOSIS AND TESTING - PCV VALVE - 3.7L
V-6/ 4.7L V-8
(1) Disconnect PCV line/hose (Fig. 19) by discon-
necting rubber connecting hose at PCV valve fitting.
(2) Remove PCV valve at oil filler tube by rotating
PCV valve downward until locating tabs have been
freed at cam lock (Fig. 19). After tabs have cleared,
pull valve straight out from filler tube.To prevent
damage to PCV valve locating tabs, valve must
be pointed downward for removal. Do not force
valve from oil filler tube.
(3) After valve is removed, check condition of valve
o-ring (Fig. 19). Also, PCV valve should rattle when
shaken.
(4) Reconnect PCV valve to its connecting line/
hose.
(5) Start engine and bring to idle speed.
(6) If valve is not plugged, a hissing noise will be
heard as air passes through valve. Also, a strong vac-
uum should be felt with a finger placed at valve
inlet.
(7) If vacuum is not felt at valve inlet, check line/
hose for kinks or for obstruction. If necessary, clean
out intake manifold fitting at rear of manifold. Do
this by turning a 1/4 inch drill (by hand) through the
fitting to dislodge any solid particles. Blow out the
fitting with shop air. If necessary, use a smaller drill
to avoid removing any metal from the fitting.
(8)Do not attempt to clean the old PCV valve.
(9) Return PCV valve back to oil filler tube by
placing valve locating tabs (Fig. 19) into cam lock.
Press PCV valve in and rotate valve upward. A slight
click will be felt when tabs have engaged cam lock.
Valve should be pointed towards rear of vehicle.
(10) Connect PCV line/hose and connecting rubber
hose to PCV valve.
(11) Disconnect rubber hose from fresh air fitting
at air cleaner resonator box. Start engine and bring
to idle speed. Hold a piece of stiff paper (such as a
parts tag) loosely over the opening of the discon-
nected rubber hose.
(12) The paper should be drawn against the hose
opening with noticeable force. This will be after
allowing approximately one minute for crankcase
pressure to reduce.
(13) If vacuum is not present, disconnect each PCV
system hose at top of each crankcase breather (Fig.
20). Check for obstructions or restrictions.
(14) If vacuum is still not present, remove each
PCV system crankcase breather (Fig. 20) from each
cylinder head. Check for obstructions or restrictions.
If plugged, replace breather. Tighten breather to 12
N´m (106 in. lbs.) torque. Do not attempt to clean
breather.(15) If vacuum is still not present, disconnect each
PCV system hose at each fitting, and at each check
valve (Fig. 21). Check for obstructions or restrictions.
Fig. 19 PCV VALVE - 3.7L V-6 / 4.7L V-8
1 - O-RING
2 - LOCATING TABS
3 - CAM LOCK
4 - OIL FILLER TUBE
5 - PCV LINE/HOSE
6 - P C V VA LV E
Fig. 20 CRANKCASE BREATHERS (2) - 3.7L V-6 /
4.7L V-8
1 - CRANKCASE BREATHERS (2)
2 - REAR OF ENGINE
25 - 20 EVAPORATIVE EMISSIONSDR
PCV VALVE (Continued)

5.7L V-8
(1) Clean out intake manifold opening.
(2) Check condition of 2 o-rings on PCV valve.
(3) Apply engine oil to 2 o-rings.
(4) Place PCV valve into intake manifold and
rotate 90 degrees clockwise for installation.
VACUUM LINES
DESCRIPTION
A vacuum schematic for emission related items can
be found on the vehicles VECI label. Refer to Vehicle
Emission Control Information (VECI) Label for label
location.
VAPOR CANISTER
DESCRIPTION
Two, maintenance free, EVAP canisters are used.
Both canisters are mounted into a two-piece support
bracket located near the front of the fuel tank (Fig.
23).
OPERATION
Two, maintenance free, EVAP canisters are
used.The EVAP canisters are filled with granules of
an activated carbon mixture. Fuel vapors entering
the EVAP canisters are absorbed by the charcoal
granules.
Fuel tank pressure vents into the EVAP canisters.
Fuel vapors are temporarily held in the canisters
until they can be drawn into the intake manifold.
The duty cycle EVAP canister purge solenoid allows
the EVAP canisters to be purged at predetermined
times and at certain engine operating conditions.
REMOVAL
Two, maintenance free, EVAP canisters are used.
Both canisters are mounted into a two-piece support
bracket located near the front of the fuel tank (Fig.
23).
(1) Raise and support vehicle.
(2) Remove fuel tubes/lines at each EVAP canister.
Note location of tubes/lines before removal for easier
installation.
(3) Remove lower support bracket (Fig. 24).
(4) Remove mounting nuts at top of each canister
(Fig. 24).
(5) Remove each canister from upper support
bracket.
INSTALLATION
(1) Place each canister into upper support bracket
and install nuts. Refer to Torque Specifications.
(2) Install lower support bracket. Refer to Torque
Specifications.
(3) Carefully install vapor/vacuum lines.The
vapor/vacuum lines and hoses must be firmly
connected. Also check the vapor/vacuum lines
at the LDP, LDP filter and EVAP canister purge
solenoid for damage or leaks. If a leak is
present, a Diagnostic Trouble Code (DTC) may
be set.
Fig. 23 LOCATION, EVAP CANISTERS
1 - LDP
2 - LDP MOUNTING BOLT
3 - ELEC. CONNEC.
4 - FILTER MOUNTING BOLT
5 - LDP FILTER
6 - CONNECTING HOSE
7 - EVAP CANISTER MOUNTING BRACKET
8 - EVAP CANISTERS (2)
25 - 22 EVAPORATIVE EMISSIONSDR
PCV VALVE (Continued)

The NVLD device is designed with a normally open
vacuum switch, a normally closed solenoid, and a
seal, which is actuated by both the solenoid and a
diaphragm. The NVLD is located on the atmospheric
vent side of the canister. The NVLD assembly may
be mounted on top of the canister outlet, or in-line
between the canister and atmospheric vent filter. The
normally open vacuum switch will close with about 19
H2O (0.25 KPA) vacuum in the evaporative system.
The diaphragm actuates the switch. This is above the
opening point of the fuel inlet check valve in the fill
tube so cap off leaks can be detected. Submerged fill
systems must have recirculation lines that do not
have the in-line normally closed check valve that pro-
tects the system from failed nozzle liquid ingestion,
in order to detect cap off conditions.
The normally closed valve in the NVLD is intended
to maintain the seal on the evaporative system dur-
ing the engine off condition. If vacuum in the evapo-
rative system exceeds 39to 69H2O (0.75 to 1.5 KPA),
the valve will be pulled off the seat, opening the seal.
This will protect the system from excessive vacuum
as well as allowing sufficient purge flow in the event
that the solenoid was to become inoperative.
The solenoid actuates the valve to unseal the can-
ister vent while the engine is running. It also will be
used to close the vent during the medium and large
leak tests and during the purge flow check. This sole-
noid requires initial 1.5 amps of current to pull the
valve open but after 100 ms. will be duty cycled down
to an average of about 150 mA for the remainder of
the drive cycle.
Another feature in the device is a diaphragm that
will open the seal in the NVLD with pressure in the
evaporative system. The device will9blow off9at
about 0.59H2O (0.12 KPA) pressure to permit the
venting of vapors during refueling. An added benefit
to this is that it will also allow the tank to9breathe9
during increasing temperatures, thus limiting the
pressure in the tank to this low level. This is benefi-
cial because the induced vacuum during a subse-
quent declining temperature will achieve the switch
closed (pass threshold) sooner than if the tank had to
decay from a built up pressure.
The device itself has 3 wires: Switch sense, sole-
noid driver and ground. It also includes a resistor to
protect the switch from a short to battery or a short
to ground. The NGC utilizes a high-side driver to
energize and duty-cycle the solenoid.REMOVAL
The NVLD pump and filter are attached to the
front of the EVAP canister mounting bracket (Fig.
25). This is located near the front of the fuel tank.
The pump and filter are replaced (serviced) as one
unit.
(1) Raise and support vehicle.
(2) Carefully remove pump hose clamp and hose at
filter.
(3) Carefully remove other vapor/vacuum hose at
pump.
(4) Disconnect 3±way electrical connector at pump.
(5) The NVLD pump snaps onto the EVAP canister
mounting bracket. Press on release tab (Fig. 26)
while sliding pump from bracket.
Fig. 25 NVLD PUMP LOCATION
1 - EVAP CANISTER MOUNTING BRACKET
2 - NVLD PUMP
3 - FILTER
25 - 24 EVAPORATIVE EMISSIONSDR
NATURAL VAC LEAK DETECTION ASSY (Continued)