evap leak detection JEEP LIBERTY 2002 KJ / 1.G User Guide

(11) Remove module lockring (Fig. 40) using a
brass drift and hammer (counter-clockwise).
(12) Carefully lift upper section of pump module
from fuel tank a few inches(lift upper section
from tank very slowly until rubber gasket can
be retained. If not, gasket will fall into fuel
tank).
(13) Using an approved gas holding tank, drain
fuel tank through fuel pump module opening.
Tank Removal
(1) After draining tank, temporarily place upper
section of fuel pump module back into fuel tank.
(2) Raise vehicle.
(3) If equipped, remove fuel tank skid plate and
tow hooks. Certain equipment packages will also
require removal of the trailer hitch. Refer to Tow
Hooks, Trailer Hitch or Skid Plate in 23, Body for
removal/installation procedures.
(4) Disconnect fuel filter ground strap.
(5) Disconnect fuel filter outlet line from body
retention clip located on frame near front/center of
tank (Fig. 41). Place a small screwdriver into side of
clip and twist for removal. Also disconnect Leak
Detection Pump (LDP) line (Fig. 41) from this clip.(6) Remove both 3/4º hoses at sides of Leak Detec-
tion Pump (LDP) (Fig. 41).
(7) Disconnect 3/4º flow management valve hose
(Fig. 41) at EVAP canister.
(8) Remove fuel fill hose clamp (Fig. 42) at fuel
tank, and disconnect hose from fuel tank.
(9) A third fuel line is attached to bottom of fuel
filter. The disconnection point (quick-connect fitting)
for this 3rd line is approximately 1 foot from front of
tank towards front of vehicle (Fig. 41). Clean connec-
tion point before disconnection. Disconnect by press-
ing on tabs at side of quick-connect fitting. Also
disconnect LDP vent line near this same point.
(10) Disconnect 2 vacuum/vent hoses from plastic
retention clip at left/front of fuel tank line (Fig. 41).
(11) Support tank with a hydraulic jack.
(12) Remove 4 fuel tank strap bolts (Fig. 41) (2 at
front of tank; 2 at rear of tank), and remove both
tank support straps (Fig. 41).
(13) Carefully lower tank a few inches and discon-
nect electrical connector at top of LDP (Fig. 43). To
disconnect electrical connector: Push upward on red
colored tab to unlock. Push on black colored tab
while removing connector.
Fig. 40 TOP OF FUEL PUMP MODULE
1 - LOCK RING
2 - ALIGNMENT NOTCH
3 - FUEL FILTER FITTINGS (2)
4 - ORVR SYSTEM HOSE AND CLAMP
5 - FLOW MANAGEMENT VALVE
6 - ELECTRICAL CONNECTOR
7 - LEAK DETECTION PUMP
8 - FUEL TANK CHECK (CONTROL) VALVE
9 - FUEL PUMP MODULE (UPPER SECTION)Fig. 41 FRONT OF FUEL TANK
1 - TANK MOUNTING BOLTS (4)
2 - TANK MOUNTING STRAPS (2)
3 - LEAK DETECTION PUMP (LDP)
4 - BODY RETENTION CLIP (CENTER)
5 - LDP HOSES
6 - HOSE TO FUEL MANAGEMENT VALVE
7 - BODY RETENTION CLIP (LEFT/FRONT)
8 - QUICK-CONECT FITTING
9 - LDP LINE
14 - 26 FUEL DELIVERYKJ
FUEL TANK (Continued)

(14) Continue lowering tank while guiding remain-
ing hoses and lines.
(15) If fuel tank is to be replaced, remove LDP,
fuel filter and fuel pump module from tank. Refer to
Leak Detection Pump, Fuel Filter and Fuel Pump
Module Removal/Installation procedures.
INSTALLATION
(1) If fuel tank is to be replaced, install LDP, fuel
filter and fuel pump module to tank. Refer to Leak
Detection Pump, Fuel Filter and Fuel Pump Module
Removal/Installation procedures.
(2) Position fuel tank to hydraulic jack.
(3) Raise tank while carefully guiding vent tubes/
hoses through frame rail and crossmember. Before
tank reaches body, connect electrical connector to
Leak Detection Pump (LDP).
(4) Continue raising tank until positioned to body.
(5) Attach two fuel tank mounting straps and 4
mounting bolts. Tighten bolts to 61 N´m (45 ft. lbs.)
torque.
(6) Connect 2 hoses to body retention clip at left/
front of tank.
(7) Connect fuel filter fuel line to main fuel line
(snaps together). After connecting, snap this line into
body retention clip. Also connect LDP vacuum hose
near this point.(8) Install fuel fill hose and hose clamp to fuel
tank fitting. Rotate hose until white painted index
mark on hose (Fig. 42) is located between alignment
notches on fuel tank fitting. Tighten clamp to 3.4
N´m (30 in. lbs.) torque.
(9) Connect fresh air and recirculation lines to fuel
fill tube.
(10) Connect 3/4º lines to Leak Detection Pump
(LDP).
(11) Connect 3/4º flow management valve hose to
EVAP canister.
(12) Snap remaining lines into body retention clip
at front/center of fuel tank.
(13) If equipped, install fuel tank skid plate,
trailer hitch and tow hooks. Refer to Tow Hooks,
Trailer Hitch or Skid Plate in 23, Body for removal/
installation procedures.
(14) Lower vehicle.
(15) Attach (snap on) 2 fuel filter fuel lines to top
of fuel pump module.
(16) Install electrical connector to top of fuel pump
module.
(17) Connect negative battery cable to battery.
(18) Fill fuel tank with fuel.
(19) Start engine and check for fuel leaks near top
of module.
(20) Apply silicone sealant to bottom of fuel pump
module metal access plate.
Fig. 42 FUEL FILL HOSE AT TANK
1 - FUEL FILL HOSE AT TANK
2 - HOSE CLAMP
3 - WHITE PAINTED INDEX MARK
4 - ALIGNMENT NOTCHES
5 - LEFT SIDE OF FUEL TANK
6 - FUEL FILL FITTINGFig. 43 LDP ELECTRICAL CONNECTOR
1 - LEAK DETECTION PUMP (LDP)
2 - ELECTRICAL CONNECTOR
3 - FUEL FILTER
KJFUEL DELIVERY 14 - 27
FUEL TANK (Continued)

(M)Malfunction Indicator Lamp (MIL) illuminated during engine operation if this DTC was recorded
(depending if required by CARB and/or EPA). MIL is displayed as an engine icon on instrument panel.
(G)Generator lamp illuminated
Generic Scan
Tool P-CodeDRB Scan Tool Display Brief Description of DTC
P1478 Battery Temp Sensor Volts Out of
LimitInternal temperature sensor input voltage out of an
acceptable range.
P1479 Transmission Fan Relay Circuit An open or shorted condition detected in the transmission
fan relay circuit.
P1480 PCV Solenoid Circuit An open or shorted condition detected in the PCV
solenoid circuit.
P1481 EATX RPM Pulse Perf EATX RPM pulse generator signal for misfire detection
does not correlate with expected value.
P1482 Catalyst Temperature Sensor Circuit
Shorted LowCatalyst temperature sensor circuit shorted low.
P1483 Catalyst Temperature Sensor Circuit
Shorted High.Catalyst temperature sensor circuit shorted high.
P1484 Catalytic Converter Overheat
DetectedA catalyst overheat condition has been detected by the
catalyst temperature sensor.
P1485 Air Injection Solenoid Circuit An open or shorted condition detected in the air assist
solenoid circuit.
P1486 Evap Leak Monitor Pinched Hose
FoundLDP has detected a pinched hose in the evaporative hose
system.
P1487 Hi Speed Rad Fan CTRL Relay
CircuitAn open or shorted condition detected in the control
circuit of the #2 high speed radiator fan control relay.
P1488 Auxiliary 5 Volt Supply Output Too
LowAuxiliary 5 volt sensor feed is sensed to be below an
acceptable limit.
P1488 5 Volt Supply Voltage Low Sensor supply voltage for ECM sensors is too low.
P1489 High Speed Fan CTRL Relay Circuit An open or shorted condition detected in the control
circuit of the high speed radiator fan control relay.
P1490 Low Speed Fan CTRL Relay Circuit An open or shorted condition detected in control circuit of
the low speed radiator fan control relay.
P1491 Rad Fan Control Relay Circuit An open or shorted condition detected in the radiator fan
control relay control circuit. This includes PWM solid state
relays.
P1492 Ambient/Batt Temp Sen Volts Too
HighExternal temperature sensor input above acceptable
voltage.
P1492 (M) Ambient/Batt Temp Sensor Volts Too
HighBattery temperature sensor input voltage above an
acceptable range.
P1493 (M) Ambient/Batt Temp Sen Volts Too
LowExternal temperature sensor input below acceptable
voltage.
P1493 (M) Ambient/Batt Temp Sen Volts Too
LowBattery temperature sensor input voltage below an
acceptable range.
P1494 (M) Leak Detection Pump Sw or
Mechanical FaultIncorrect input state detected for the Leak Detection
Pump (LDP) pressure switch.
P1495 Leak Detection Pump Solenoid
CircuitAn open or shorted condition detected in the Leak
Detection Pump (LDP) solenoid circuit.
P1496 5 Volt Supply, Output Too Low 5 volt sensor feed is sensed to be below an acceptable
limit. ( less than 4v for 4 sec )
KJEMISSIONS CONTROL 25 - 13
EMISSIONS CONTROL (Continued)

LEAK DETECTION PUMP MONITOR (IF EQUIPPED)
The leak detection assembly incorporates two pri-
mary functions: it must detect a leak in the evapora-
tive system and seal the evaporative system so the
leak detection test can be run.
The primary components within the assembly are:
A three port solenoid that activates both of the func-
tions listed above; a pump which contains a switch,
two check valves and a spring/diaphragm, a canister
vent valve (CVV) seal which contains a spring loaded
vent seal valve.
Immediately after a cold start, between predeter-
mined temperature thresholds limits, the three port
solenoid is briefly energized. This initializes the
pump by drawing air into the pump cavity and also
closes the vent seal. During non test conditions the
vent seal is held open by the pump diaphragm
assembly which pushes it open at the full travel posi-
tion. The vent seal will remain closed while the
pump is cycling due to the reed switch triggering of
the three port solenoid that prevents the diaphragm
assembly from reaching full travel. After the brief
initialization period, the solenoid is de-energized
allowing atmospheric pressure to enter the pump
cavity, thus permitting the spring to drive the dia-
phragm which forces air out of the pump cavity and
into the vent system. When the solenoid is energized
and de energized, the cycle is repeated creating flow
in typical diaphragm pump fashion. The pump is con-
trolled in 2 modes:
Pump Mode:The pump is cycled at a fixed rate to
achieve a rapid pressure build in order to shorten the
overall test length.
Test Mode:The solenoid is energized with a fixed
duration pulse. Subsequent fixed pulses occur when
the diaphragm reaches the Switch closure point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5º
water. The cycle rate of pump strokes is quite rapid
as the system begins to pump up to this pressure. As
the pressure increases, the cycle rate starts to drop
off. If there is no leak in the system, the pump would
eventually stop pumping at the equalized pressure. If
there is a leak, it will continue to pump at a rate rep-
resentative of the flow characteristic of the size of the
leak. From this information we can determine if the
leak is larger than the required detection limit (cur-
rently set at .040º orifice by CARB). If a leak is
revealed during the leak test portion of the test, the
test is terminated at the end of the test mode and no
further system checks will be performed.
After passing the leak detection phase of the test,
system pressure is maintained by turning on the
LDP's solenoid until the purge system is activated.
Purge activation in effect creates a leak. The cycle
rate is again interrogated and when it increases dueto the flow through the purge system, the leak check
portion of the diagnostic is complete.
The canister vent valve will unseal the system
after completion of the test sequence as the pump
diaphragm assembly moves to the full travel position.
Evaporative system functionality will be verified by
using the stricter evap purge flow monitor. At an
appropriate warm idle the LDP will be energized to
seal the canister vent. The purge flow will be clocked
up from some small value in an attempt to see a
shift in the 02 control system. If fuel vapor, indicated
by a shift in the 02 control, is present the test is
passed. If not, it is assumed that the purge system is
not functioning in some respect. The LDP is again
turned off and the test is ended.
MISFIRE MONITOR
Excessive engine misfire results in increased cata-
lyst temperature and causes an increase in HC emis-
sions. Severe misfires could cause catalyst damage.
To prevent catalytic convertor damage, the PCM
monitors engine misfire.
The Powertrain Control Module (PCM) monitors
for misfire during most engine operating conditions
(positive torque) by looking at changes in the crank-
shaft speed. If a misfire occurs the speed of the
crankshaft will vary more than normal.
FUEL SYSTEM MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide. The catalyst works best
when the Air Fuel (A/F) ratio is at or near the opti-
mum of 14.7 to 1.
The PCM is programmed to maintain the optimum
air/fuel ratio of 14.7 to 1. This is done by making
short term corrections in the fuel injector pulse width
based on the O2S sensor output. The programmed
memory acts as a self calibration tool that the engine
controller uses to compensate for variations in engine
specifications, sensor tolerances and engine fatigue
over the life span of the engine. By monitoring the
actual fuel-air ratio with the O2S sensor (short term)
and multiplying that with the program long-term
(adaptive) memory and comparing that to the limit,
it can be determined whether it will pass an emis-
sions test. If a malfunction occurs such that the PCM
cannot maintain the optimum A/F ratio, then the
MIL will be illuminated.
CATALYST MONITOR
To comply with clean air regulations, vehicles are
equipped with catalytic converters. These converters
reduce the emission of hydrocarbons, oxides of nitro-
gen and carbon monoxide.
25 - 18 EMISSIONS CONTROLKJ
EMISSIONS CONTROL (Continued)

EVAPORATIVE EMISSIONS
TABLE OF CONTENTS
page page
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAPORATION CONTROL
SYSTEM............................24
SPECIFICATIONS
TORQUE............................26
EVAP/PURGE SOLENOID
DESCRIPTION.........................27
OPERATION...........................27
REMOVAL.............................27
INSTALLATION.........................27
FUEL FILLER CAP
DESCRIPTION.........................27
OPERATION...........................27
LEAK DETECTION PUMP
DESCRIPTION.........................27
OPERATION...........................28
REMOVAL.............................28INSTALLATION.........................28
ORVR
DESCRIPTION.........................29
OPERATION...........................29
P C V VA LV E
DESCRIPTION.........................29
OPERATION...........................31
DIAGNOSIS AND TESTING - PCV VALVE.....31
REMOVAL.............................32
INSTALLATION.........................32
VACUUM LINES
DESCRIPTION.........................33
VAPOR CANISTER
DESCRIPTION.........................33
OPERATION...........................33
REMOVAL.............................33
INSTALLATION.........................33
EVAPORATIVE EMISSIONS
DESCRIPTION - EVAPORATION CONTROL
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 the control valve located in the top section of
the fuel pump module, through the fuel management
valve, and through vent hoses and tubes to a char-
coal filled evaporative canister. The canister tempo-
rarily holds the vapors. The Powertrain Control
Module (PCM) allows intake manifold vacuum to
draw vapors into the combustion chambers during
certain operating conditions.
Gas powered engines use a duty cycle purge sys-
tem. The PCM controls vapor flow by operating theduty cycle EVAP purge solenoid. Refer to Duty Cycle
EVAP Canister Purge Solenoid.
When equipped with certain emissions packages, a
Leak Detection Pump (LDP) will be used as part of
the evaporative system for OBD II requirements.
Also refer to Leak Detection Pump.
Vehicles powered with gasoline engines are also
equipped with ORVR (On-Board Refueling Vapor
Recovery). Refer to ORVR for additional information.
NOTE: The evaporative system uses specially man-
ufactured lines/hoses. If replacement becomes nec-
essary, only use fuel resistant, low permeation
hose.
Certain components can be found in (Fig. 1).
25 - 24 EVAPORATIVE EMISSIONSKJ

Fig. 1 FUEL DELIVERY COMPONENTS
1 - FUEL TANK 10 - EVAP CANISTER
2 - FUEL TANK STRAPS 11 - FLOW MANAGEMENT VALVE
3 - FUEL PUMP MODULE LOCK RING 12 - FRESH AIR TUBE
4 - CHECK (CONTROL) VALVE 13 - HOSE SLEEVE
5 - FUEL PUMP MODULE FLANGE 14 - FUEL FILTER
6 - FUEL FILL HOSE 15 - LEAK DETECTION PUMP
7 - FRESH AIR FILTER 16 - HEAT SHIELD
8 - FUEL FILL CAP/BEZEL 17 - SKID PLATE
9 - FUEL FILL TUBE
KJEVAPORATIVE EMISSIONS 25 - 25
EVAPORATIVE EMISSIONS (Continued)

SPECIFICATIONS
TORQUE
DESCRIPTION N-m Ft. Lbs. In. Lbs.
Accelerator Pedal Bracket
Mounting Nuts12 - 105
Crankshaft Position Sensor - 2.4L 28 21 -
Crankshaft Position Sensor - 3.7L 28 21 -
Camshaft Position Sensor - 2.4L 12 - 106
Camshaft Position Sensor - 3.7L 12 - 106
Engine Coolant Temperature
Sensor11 - 9 6
EVAP Canister-to-Body Bolts 48 35 -
EVAP Canister-to-Canis. Bracket
Bolt/Nut11 - 100
Fuel Filler Hose Clamp at Tank 3 - 30
Fuel Filler Housing-to-Body
Screws2-17
Fuel Filter Mounting Nut at Tank 5.5 - 49
Fuel Pump Module Access Plate
Nuts3-26
Fuel Rail Mounting Bolts - 3.7L 11 - 100
Fuel Rail Mounting Bolts - 2.4L 28 - 250
Fuel Tank Heat Sheild Nuts 5.5 - 49
Fuel Tank Mounting Strap Bolts 61 45 -
Fuel Tank Skid Plate and Trailer
Hitch88 65 -
IAC Motor Mounting Screws 7 - 60
Leak Detection Pump Mounting
Bracket-to-Fuel Tank Nuts5.5 - 49
Leak Detection Pump-to-Bracket
Nuts1.2 - 11
Map Sensor Mounting Screws 3 - 25
PCM-to-Mounting Bracket
Mounting Screws4-35
Power Steering Pressure Switch 14-22 - 124-195
TPS Mounting Screws 7 - 60
Throttle Body Mounting Bolts 11 - 100
Oxygen Sensors 30 22 -
25 - 26 EVAPORATIVE EMISSIONSKJ
EVAPORATIVE EMISSIONS (Continued)

EVAP/PURGE SOLENOID
DESCRIPTION
The duty cycle EVAP canister purge solenoid (DCP)
is located in the engine compartment. It is attached
to a bracket located between the battery and the
Power Distribution Center (PDC). The EVAP system
test port is located near the solenoid.
OPERATION
The duty cycle EVAP canister purge solenoid (DCP)
regulates the rate of vapor flow from the EVAP can-
ister to the intake manifold. The Powertrain Control
Module (PCM) operates the solenoid.
During the cold start warm-up period and the hot
start time delay, the PCM does not energize the sole-
noid. When de-energized, no vapors are purged. The
PCM de-energizes the solenoid during open loop oper-
ation.
The engine enters closed loop operation after it
reaches a specified temperature and the time delay
ends. During closed loop operation, the PCM cycles
(energizes and de-energizes) the solenoid 5 or 10
times per second, depending upon operating condi-
tions. The PCM varies the vapor flow rate by chang-
ing solenoid pulse width. Pulse width is the amount
of time that the solenoid is energized. The PCM
adjusts solenoid pulse width based on engine operat-
ing condition.
REMOVAL
The duty cycle EVAP canister purge solenoid (DCP)
is located in the engine compartment (Fig. 2). It is
attached to a bracket located between the battery
and the Power Distribution Center (PDC). The EVAP
system test port is located near the solenoid (Fig. 2).
(1) Disconnect electrical wiring connector at sole-
noid.
(2) Disconnect vacuum harness at solenoid.
(3) Remove solenoid and its support bracket (pull
straight up).
INSTALLATION
(1) Slip EVAP canister purge solenoid onto its
mounting bracket.
(2) Connect vacuum harness to solenoid.
(3) Connect electrical connector to solenoid.
FUEL FILLER CAP
DESCRIPTION
The plastic fuel tank filler tube cap is threaded
onto the end of the fuel fill tube. All models are
equipped with a 1/4 turn cap.
OPERATION
The loss of any fuel or vapor out of fuel filler tube
is prevented by the use of a pressure-vacuum fuel fill
cap. Relief valves inside the cap will release fuel tank
pressure at predetermined pressures. Fuel tank vac-
uum will also be released at predetermined values.
This cap must be replaced by a similar unit if
replacement is necessary. This is in order for the sys-
tem to remain effective.
CAUTION: Remove fill cap before servicing any fuel
system component to relieve tank pressure. If
equipped with an ORVR system and a Leak Detec-
tion Pump (LDP), the cap must be tightened
securely. If cap is left loose, a Diagnostic Trouble
Code (DTC) may be set.
LEAK DETECTION PUMP
DESCRIPTION
The Leak Detection Pump (LDP) is bolted to the
front of the fuel tank (Fig. 1).
The Leak Detection Pump (LDP) is used only with
certain emission packages.
The LDP is a device used to detect a leak in the
evaporative system.
Fig. 2 EVAP / PURGE SOLENOID LOCATION
1 - BATTERY
2 - EVAP/PURGE SOLENOID LOCATION
3 - MOUNTING BRACKET
4 - POWER DISTRIBUTION CENTER (PDC)
5 - SOLENOID ELECTRICAL CONNECTOR
6 - EVAP SYSTEM TEST PORT
KJEVAPORATIVE EMISSIONS 25 - 27

The pump contains a 3 port solenoid, a pump that
contains a switch, a spring loaded canister vent valve
seal, 2 check valves and a spring/diaphragm.
OPERATION
Immediately after a cold start, engine temperature
between 40ÉF and 86ÉF, the 3 port solenoid is briefly
energized. This initializes the pump by drawing air
into the pump cavity and also closes the vent seal.
During non-test test conditions, the vent seal is held
open by the pump diaphragm assembly which pushes
it open at the full travel position. The vent seal will
remain closed while the pump is cycling. This is due
to the operation of the 3 port solenoid which prevents
the diaphragm assembly from reaching full travel.
After the brief initialization period, the solenoid is
de-energized, allowing atmospheric pressure to enter
the pump cavity. This permits the spring to drive the
diaphragm which forces air out of the pump cavity
and into the vent system. When the solenoid is ener-
gized and de-energized, the cycle is repeated creating
flow in typical diaphragm pump fashion. The pump
is controlled in 2 modes:
PUMP MODE:The pump is cycled at a fixed rate
to achieve a rapid pressure build in order to shorten
the overall test time.
TEST MODE:The solenoid is energized with a
fixed duration pulse. Subsequent fixed pulses occur
when the diaphragm reaches the switch closure
point.
The spring in the pump is set so that the system
will achieve an equalized pressure of about 7.5 inches
of water.
When the pump starts, the cycle rate is quite high.
As the system becomes pressurized pump rate drops.
If there is no leak the pump will quit. If there is a
leak, the test is terminated at the end of the test
mode.
If there is no leak, the purge monitor is run. If the
cycle rate increases due to the flow through the
purge system, the test is passed and the diagnostic is
complete.
The canister vent valve will unseal the system
after completion of the test sequence as the pump
diaphragm assembly moves to the full travel position.
REMOVAL
The Leak Detection Pump (LDP) is attached (bolt-
ed) to the front of the fuel tank (Fig. 3). The LDP
fresh air filter is located on the end of a hose. This
hose is attached to the fuel fill tube assembly below
and near the fuel fill opening (Fig. 1). The LDP and
LDP filter are typically replaced (serviced) as one
unit.
(1) Raise vehicle.(2) Carefully remove two 3/4º vent hoses at sides
of LDP.
(3) Carefully remove other vapor/vacuum hoses
from LDP.
(4) Place a hydraulic jack under fuel tank.
(5) Loosen 2 fuel tank strap mounting bolts at
front of tank about 10 turns.
(6) Lower front of fuel tank about 1/2º.
(7) Remove 2 LDP mounting nuts (Fig. 3) and
lower LDP slightly to gain access to electrical connec-
tor (Fig. 4).
(8) Disconnect electrical connector at LDP. To dis-
connect: Slide red colored tab upward. Push on black
colored tab while removing connector.
(9) Remove LDP from vehicle.
INSTALLATION
The Leak Detection Pump (LDP) is attached (bolt-
ed) to the front of the fuel tank. The LDP filter is
located on the end of a hose. This hose is attached to
the fuel fill tube assembly below and near the fuel
fill opening. The LDP and LDP filter are replaced
(serviced) as one unit.
(1) Install electrical connector to LDP. Push red
colored tab downward to lock connector to LDP.
(2) Position LDP and LDP bracket to fuel tank
mounting studs and install 2 nuts. Tighten nuts to 1
N´m (11 in. lbs.) torque.
(3) Raise fuel tank to body and tighten 2 strap
bolts to 61 N´m (45 ft. lbs.) torque.
Fig. 3 LDP LOCATION / MOUNTING
1 - LDP
2 - FLOW MANAGEMENT VALVE
3 - MOUNTING NUTS
4 - FRONT OF FUEL TANK
25 - 28 EVAPORATIVE EMISSIONSKJ
LEAK DETECTION PUMP (Continued)

(4) Carefully install vapor/vacuum lines to LDP,
and install hose to LDP filter.The vapor/vacuum
lines and hoses must be firmly connected.
Check the vapor/vacuum lines at the LDP, LDP
filter and EVAP canister duty cycle purge sole-
noid for damage or leaks. If a leak is present, a
Diagnostic Trouble Code (DTC) may be set.
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 (Fig. 1).
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. Cer-
tain ORVR components can be found in (Fig. 1).
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
2.4L
The 2.4L 4-cylinder engine is equipped with a
closed crankcase ventilation system and a Positive
Crankcase Ventilation (PCV) valve.
This system consists of:
²a PCV valve attached to the left/front side of the
valve cover (Fig. 5). It is secured with 1 bolt. An
o-ring is used to seal valve to valve cover (Fig. 6).
²the air cleaner housing
²tubes and hoses to connect the system compo-
nents.
3.7L
The 3.7L V-6 engine is equipped with a closed
crankcase ventilation system and a Positive Crank-
case Ventilation (PCV) valve.
This system consists of:
²a PCV valve mounted to the oil filler housing
(Fig. 7). 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. 8).
²tubes and hoses to connect the system compo-
nents.
Fig. 4 LDP ELECTRICAL CONNECTOR
1 - LEAK DETECTION PUMP (LDP)
2 - ELECTRICAL CONNECTOR
3 - FUEL FILTER
KJEVAPORATIVE EMISSIONS 25 - 29
LEAK DETECTION PUMP (Continued)