2002 JEEP LIBERTY Vacuum

VACUUM RESERVOIR
DESCRIPTION
The vacuum reservoir is a plastic storage tank con-
nected to an engine vacuum source by vacuum lines.
OPERATION
The vacuum reservoir is used to supply the vac-
uum needed to maintain proper speed control opera-
tion when engine vacuum drops, such as in climbing
a grade while driving. A one-way check valve is used
in the vacuum line between the reservoir and the
vacuum source. This check valve is used to trap
engine vacuum in the reservoir. On certain vehicle
applications, this reservoir is shared with the heat-
ing/air-conditioning system. The vacuum reservoir
cannot be repaired and must be replaced if faulty.
DIAGNOSIS AND TESTING - VACUUM
RESERVOIR
(1) Disconnect vacuum hose at speed control servo
and install a vacuum gauge into the disconnected
hose.
(2) Start engine and observe gauge at idle. Vac-
uum gauge should read at least ten inches of mer-
cury.
(3) If vacuum is less than ten inches of mercury,
determine source of leak. Check vacuum line to
engine for leaks. Also check actual engine intake
manifold vacuum. If manifold vacuum does not meet
this requirement, check for poor engine performance
and repair as necessary.
(4) If vacuum line to engine is not leaking, check
for leak at vacuum reservoir. To locate and gain
access to reservoir, refer to Vacuum Reservoir Remov-
al/Installation in this group. Disconnect vacuum line
at reservoir and connect a hand-operated vacuum
pump to reservoir fitting. Apply vacuum. Reservoir
vacuum should not bleed off. If vacuum is being lost,
replace reservoir.
(5) Verify operation of one-way check valve and
check it for leaks.Certain models may be
equipped with 2 check-valves.
(a) Locate one-way check valve. The valve is
located in vacuum line between vacuum reservoir
and engine vacuum source. Disconnect vacuum
hoses (lines) at each end of valve.
(b) Connect a hand-operated vacuum pump to
reservoir end of check valve. Apply vacuum. Vac-
uum should not bleed off. If vacuum is being lost,
replace one-way check valve.
(c) Connect a hand-operated vacuum pump to
vacuum source end of check valve. Apply vacuum.
Vacuum should flow through valve. If vacuum is
not flowing, replace one-way check valve. Seal thefitting at opposite end of valve with a finger and
apply vacuum. If vacuum will not hold, diaphragm
within check valve has ruptured. Replace valve.
REMOVAL
The vacuum reservoir is located behind, and at the
outer end of the instrument panel (Fig. 8). To gain
access for testing or removal, remove glovebox assem-
bly. Also remove fuse box access cover panel at end of
instrument panel. On vehicles equipped with LHD
(Left Hand Drive), this fuse access panel is located at
right end of instrument panel. On vehicles equipped
with RHD (Right Hand Drive), this access panel is
located at left end of instrument panel.
(1) Remove glovebox assembly. Access to reservoir
vacuum line and fitting can now be made.
(2) Remove vacuum line at reservoir.
(3) Remove fuse access cover panel at end of
instrument panel.
(4) Through fuse access opening, remove 2 horizon-
tally mounted screws (Fig. 8).
(5) From bottom of instrument panel, remove 1
vertically mounted screw (Fig. 9).
(6) Remove reservoir from instrument panel.
Fig. 8 VACUUM RESERVOIR LOCATION
1 - VACUUM RESERVOIR
2 - HORIZONTAL MOUNTING SCREWS
3 - OUTBOARD END OF I.P.
KJSPEED CONTROL 8P - 7

INSTALLATION
The vacuum reservoir is located behind, and at the
outer end of the instrument panel. To gain access for
testing or removal, remove glovebox assembly. Also
remove fuse box access cover panel at end of instru-
ment panel. On vehicles equipped with LHD (Left
Hand Drive), this fuse access panel is located at right
end of instrument panel. On vehicles equipped with
RHD (Right Hand Drive), this access panel is located
at left end of instrument panel.
(1) Position reservoir to instrument panel.
(2) Install 3 mounting screws and tighten. Refer to
torque specifications.
(3) Connect vacuum line to reservoir fitting.
(4) Install glovebox assembly.
(5) Install fuse box access cover panel.
Fig. 9 VACUUM RESERVOIR REMOVE/INSTALL
1 - VACUUM RESERVOIR
2 - HORIZONTAL MOUNTING SCREWS (2)
3 - VERTICAL MOUNTING SCREW (1)
8P - 8 SPEED CONTROLKJ
VACUUM RESERVOIR (Continued)

POWERTRAIN CONTROL MODULE-C2 (GAS) - WHITE 32 WAY
CAV CIRCUIT FUNCTION
13 - -
14 - -
15 K12 18TN FUEL INJECTOR NO. 2 DRIVER
16 K14 18LB/BR FUEL INJECTOR NO. 4 DRIVER
17 K173 18LG RADIATOR FAN RELAY CONTROL
18 - -
19 C18 18DB A/C PRESSURE SIGNAL
20 - -
21 - -
22 - -
23 G60 18GY/YL ENGINE OIL PRESSURE SENSOR SIGNAL
24 - -
25 - -
26 - -
27 - -
28 - -
29 - -
30 - -
31 K6 18VT/WT 5 VOLT SUPPLY
32 - -
POWERTRAIN CONTROL MODULE-C3 (GAS) - LT. GRAY 32 WAY
CAV CIRCUIT FUNCTION
1 C13 18DG A/C COMPRESSOR CLUTCH RELAY CONTROL
2- -
3 K51 18DB/YL AUTO SHUT DOWN RELAY CONTROL
4 V36 18TN/RD SPEED CONTROL VACUUM SOLENOID CONTROL
5 V35 18LG/RD SPEED CONTROL VENT SOLENOID CONTROL
6 K90 18TN (M/T) CLUTCH INTERLOCK RELAY CONTROL
7 K42 18DB/LB (3.7L) KNOCK SENSOR NO. 1 SIGNAL
7 K42 18DB/LB (2.4L) NOT USED
8 K99 18BR/OR OXYGEN SENSOR 1/1 HEATER CONTROL
9 K512 18RD/YL OXYGEN SENSOR DOWNSTEAM RELAY CONTROL
10 K106 18WT/DG LEAK DETECTION PUMP SOLENOID CONTROL
11 V32 18YL/RD SPEED CONTROL SUPPLY
12 F142 18OR/DG FUSED AUTO SHUT DOWN RELAY SENSE INPUT
13 T10 18YL/DG TORQUE MANAGEMENT REQUEST SENSE
14 K107 18OR LEAK DETECTION PUMP SWITCH SENSE
15 K118 18PK/YL BATTERY TEMPERATURE SENSOR SIGNAL
16 K299 18BR/WT (2.4L) OXYGEN SENSOR 1/2 HEATER CONTROL
16 K299 18BR/WT (3.7L) OXYGEN SENSOR 2/1 HEATER CONTROL
17 B22 18DG/YL VEHICLE SPEED OUTPUT
18 K142 18GY/BK (2.4L) NOT USED
18 K142 18GY/BK (3.7L) KNOCK SENSOR NO. 2 SIGNAL
19 K31 18BR FUEL PUMP RELAY CONTROL
20 K52 18PK/BK EVAP PURGE/SOLENOID CONTROL
21 - -
22 C21 18DB/OR A/C SWITCH SENSE
23 - -
24 K29 18WT/PK BRAKE LAMP SWITCH SENSE
25 K125 18WT/DB GENERATOR SOURCE
KJ8W-80 CONNECTOR PIN-OUTS8Wa-80-83

RIGHT VISOR/VANITY LAMP (EXCEPT BASE) - WHITE 2 WAY
CAV CIRCUIT FUNCTION
1 M1 20PK FUSED B(+)
2 M20 20BR COURTESY LAMP LOAD SHED
SENTRY KEY IMMOBILIZER MODULE (EXCEPT BASE) - BLACK 6 WAY
CAV CIRCUIT FUNCTION
1 F33 20PK/RD FUSED B(+)
2 Z11 20BK/WT GROUND
3 F1 20DB FUSED IGNITION SWITCH OUTPUT (RUN-START)
4 Z110 20BK/TN GROUND
5 D25 20YL/VT/BK PCI BUS
6- -
SHIFTER ASSEMBLY - WHITE 6 WAY
CAV CIRCUIT FUNCTION
1 E2 20OR FUSED PANEL LAMPS DIMMER SWITCH SIGNAL
2 Z21 20BK/LG GROUND
3 T6 20VT/WT OVERDRIVE OFF SWITCH SENSE
4 Z21 20BK/LG GROUND
5 F22 18DB/PK FUSED IGNITION SWITCH OUTPUT (RUN)
6 K29 20WT/PK BRAKE SWITCH SENSE
SIREN (BUILT-UP-EXPORT)-3WAY
CAV CIRCUIT FUNCTION
1 Z142 18BK/WT GROUND
2 X75 18DG SIREN SIGNAL CONTROL
3 M1 18PK FUSED B(+)
SPEED CONTROL SERVO - BLACK 4 WAY
CAV CIRCUIT FUNCTION
1 V36 18TN/RD SPEED CONTROL VACUUM SOLENOID CONTROL
2 V35 18LG/RD SPEED CONTROL VENT SOLENOID CONTROL
3 V30 18DB/RD SPEED CONTROL BRAKE SWITCH OUTPUT
4 Z212 18BK/OR GROUND
8Wa - 80 - 94 8W-80 CONNECTOR PIN-OUTSKJ

DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or
mechanical (e.g., a strange noise).
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)ÐPERFORMANCE and (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)ÐMECHANICAL for
possible causes and corrections of malfunctions.
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
DIAGNOSIS AND TESTING) and (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION - DIAGNOSIS
AND TESTING) for the fuel system diagnosis.Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following diagnosis:
²Cylinder Compression Pressure Test (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING).
²Cylinder Combustion Pressure Leakage Test
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING).
²Engine Cylinder Head Gasket Failure Diagnosis
(Refer to 9 - ENGINE/CYLINDER HEAD - DIAGNO-
SIS AND TESTING).
²Intake Manifold Leakage Diagnosis (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE MANIFOLD -
DIAGNOSIS AND TESTING).
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
CONDITION POSSIBLE CAUSE CORRECTION
ENGINE WILL NOT START 1. Weak battery 1. Charge or replace as necessary.
2. Corroded or loose battery
connections.2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to the terminals.
3. Faulty starter. 3. (Refer to 8 - ELECTRICAL/
STARTING - DIAGNOSIS AND
TESTING).
4. Faulty coil or control unit. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
5. Incorrect spark plug gap. 5. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
6. Incorrect right bank cam timing. 6. Refer to engine timing in this
section.
7. Dirt or water in fuel system. 7. Clean system and replace fuel
filter.
8.Faulty fuel pump, relay or wiring. 8.Repair or replace as necessary.
9. Faulty cam or crank sensor 9. Refer to Ignition system.
ENGINE STALLS OR ROUGH IDLE 1. Vacuum leak. 1. Inspect intake manifold and
vacuum hoses, repair or replace as
necessary.
2. Faulty crank position sensor 2. Replace crank position sensor.
4. Faulty coil. 4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
9 - 4 ENGINE - 3.7LKJ
ENGINE - 3.7L (Continued)

²Tapping the hole with a special Heli-Coil Tap, or
equivalent.
²Installing an insert into the tapped hole to bring
the hole back to its original thread size.
STANDARD PROCEDURE - ENGINE CORE AND
OIL GALLERY PLUGS
Using a blunt tool such as a drift and a hammer,
strike the bottom edge of the cup plug. With the cup
plug rotated, grasp firmly with pliers or other suit-
able tool and remove plug (Fig. 2).
CAUTION: Do not drive cup plug into the casting as
restricted cooling can result and cause serious
engine problems.
Thoroughly clean inside of cup plug hole in cylin-
der block or head. Be sure to remove old sealer.
Lightly coat inside of cup plug hole with Mopart
Stud and Bearing Mount. Make certain the new plug
is cleaned of all oil or grease. Using proper drive
plug, drive plug into hole so that the sharp edge of
the plug is at least 0.5 mm (0.020 in.) inside the
lead-in chamfer.
It is not necessary to wait for curing of the sealant.
The cooling system can be refilled and the vehicle
placed in service immediately.
REMOVAL
(1) Disconnect the battery negative cable.
(2) Remove hood. Mark hood hinge location for
reinstallation.
(3) Remove air cleaner assembly.(4) Remove radiator core support bracket.
(5) Remove fan shroud with electric fan assembly.
(6) Remove mechanical cooling fan.
(7) Remove drive belt.
NOTE: It is NOT necessary to discharge the A/C
system to remove the engine.
(8) Remove A/C compressor and secure away from
engine with lines attached.
(9) Remove generator and secure away from
engine.
NOTE: Do NOT remove the phenolic pulley from the
P/S pump. It is not required for P/S pump removal.
(10) Remove power steering pump with lines
attached and secure away from engine.
(11) Drain cooling system.
(12) Remove coolant bottle.
(13) Disconnect the heater hoses from the engine.
(14) Disconnect heater hoses from heater core and
remove hose assembly.
(15) Disconnect throttle and speed control cables.
(16) Remove upper radiator hose from engine.
(17) Remove lower radiator hose from engine.
(18) Disconnect the engine to body ground straps
at the left side of cowl.
(19) Disconnect the engine wiring harness at the
following points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(20) Remove coil over plugs.
(21) Release fuel rail pressure.
(22) Remove fuel rail and secure away from
engine.
NOTE: It is not necessary to release the quick con-
nect fitting from the fuel supply line for engine
removal.
(23) Remove the PCV hose.
(24) Remove the breather hoses.
(25) Remove the vacuum hose for the power brake
booster.
(26) Disconnect knock sensors.
(27) Remove engine oil dipstick tube.
(28) Remove intake manifold.
(29) Install engine lift plate.
Fig. 2 Core Hole Plug Removal
1 - CYLINDER BLOCK
2 - REMOVE PLUG WITH PLIERS
3 - STRIKE HERE WITH HAMMER
4 - DRIFT PUNCH
5 - CUP PLUG
9 - 10 ENGINE - 3.7LKJ
ENGINE - 3.7L (Continued)

NOTE: Recheck bolt torque for engine lift plate
before removing engine.
(30) Secure the left and right engine wiring har-
nesses away from engine.
(31) Raise vehicle.
(32) Disconnect oxygen sensor wiring.
(33) Disconnect crankshaft postion sensor.
(34) Disconnect the engine block heater power
cable, if equipped.
(35) Disconnect the front propshaft at the front
differential and secure out of way.
NOTE: It is necessary to disconnect the front prop-
shaft for access to the starter and left side exhaust
flange.
(36) Remove the starter.
(37) Remove the ground straps from the left and
right side of the block.
(38) Disconnect the right and left exhaust pipes at
the manifolds and from the crossover, and remove
from the vehicle.
NOTE: The exhaust clamps at the manifolds cannot
be reused. New clamps must be used or leaks may
occur.
NOTE: For manual transmission vehicles, the trans-
mission must be removed from the vehicle, before
the engine can be removed. The manual transmis-
sion will contact the floorpan before the engine
clears the motor mounts, so it must be removed.
(39) Remove the structural cover.
(40) Remove torque convertor bolts, and mark
location for reassembly.
(41) Remove transmission bellhousing to engine
bolts.
(42) Loosen left and right engine mount thru bolts.
NOTE: It is not necessary to completely remove
engine mount thru bolts, for engine removal.
(43) Lower the vehicle.
(44) Support the transmission with a suitable jack.
(45) Connect a suitable engine hoist to the engine
lift plate.
(46) Remove engine from vehicle.
INSTALLATION
(1) Position the engine in the vehicle.
(2) Install both left and right side engine mounts
onto engine.
(3) Raise the vehicle.(4) Install the transmission bellhousing to engine
mounting bolts. Tighten the bolts to 41 N´m (30ft.
lbs.).
(5) Tighten the engine mount thru bolts.
(6) Install the torque convertor bolts.
(7) Connect the ground straps on the left and right
side of the engine.
(8) Install the starter.
(9) Connect the crankshaft position sensor.
(10) Install the engine block heater power cable, if
equipped.
CAUTION: The structural cover requires a specific
torque sequence. Failure to follow this sequence
may cause severe damage to the cover.
(11) Install the structural cover.
NOTE: New clamps must be used on exhaust man-
ifold flanges. Failure to use new clamps may result
in exhaust leaks.
(12) Install the left and right exhaust pipes.
(13) Connect the left and right oxygen sensors.
(14) Lower vehicle.
(15) Remove the engine lift plate.
(16) Connect the knock sensors.
(17) Connect the engine to body ground straps at
the left side of the cowl.
(18) Install the intake manifold.
(19) Install the engine oil dipstick tube.
(20) Install the power brake booster vacuum hose.
(21) Install the breather hoses.
(22) Install the PCV hose.
(23) Install the fuel rail.
(24) Install the coil over plugs.
(25) Connect the engine wiring harness at the fol-
lowing points:
²Intake air temperature (IAT) sensor
²Fuel Injectors
²Throttle Position (TPS) Switch
²Idle Air Control (IAC) Motor
²Engine Oil Pressure Switch
²Engine Coolant Temperature (ECT) Sensor
²Manifold Absolute Pressure MAP) Sensor
²Camshaft Position (CMP) Sensor
²Coil Over Plugs
²Crankshaft Position Sensor
(26) Connect lower radiator hose.
(27) Connect upper radiator hose.
(28) Connect throttle and speed control cables.
(29) Install the heater hose assembly.
(30) Install coolant recovery bottle.
(31) Install the power steering pump.
(32) Install the generator.
(33) Install the A/C compressor.
(34) Install the drive belt.
KJENGINE - 3.7L 9 - 11
ENGINE - 3.7L (Continued)

INTAKE MANIFOLD
DESCRIPTION
The intake manifold (Fig. 86) is made of a compos-
ite material and features 300 mm (11.811 in.) long
runners which maximizes low end torque. The intake
manifold uses single plane sealing which consist of
six individual press in place port gaskets to prevent
leaks. The throttle body attaches directly to the
intake manifold. Eight studs and two bolts are used
to fasten the intake to the head.
DIAGNOSIS AND TESTING - INTAKE
MANIFOLD LEAKS
An intake manifold air leak is characterized by
lower than normal manifold vacuum. Also, one or
more cylinders may not be functioning.
WARNING: USE EXTREME CAUTION WHEN THE
ENGINE IS OPERATING. DO NOT STAND IN A
DIRECT LINE WITH THE FAN. DO NOT PUT YOUR
HANDS NEAR THE PULLEYS, BELTS OR THE FAN.
DO NOT WEAR LOOSE CLOTHING.
(1) Start the engine.
(2) Spray a small stream of water (Spray Bottle) at
the suspected leak area.
(3) If engine RPM'S change, the area of the sus-
pected leak has been found.
(4) Repair as required.
REMOVAL
(1) Disconnect negative cable from battery.
(2) Remove resonator assembly and air inlet hose.
(3) Disconnect throttle and speed control cables.
(4) Disconnect electrical connectors for the follow-
ing components: Refer to FUEL SYSTEM for compo-
nent locations.
²Manifold Absolute Pressure (MAP) Sensor
²Intake Air Temperature (IAT) Sensor
²Throttle Position (TPS) Sensor
²Coolant Temperature (CTS) Sensor
²Idle Air Control (IAC) Motor
(5) Disconnect vapor purge hose, brake booster
hose, speed control servo hose, positive crankcase
ventilation (PCV) hose.
(6) Disconnect generator electrical connections.
(7) Disconnect air conditioning compressor electri-
cal connections.
(8) Disconnect left and right radio suppressor
straps.
(9) Disconnect and remove ignition coil towers.
(10) Remove top oil dipstick tube retaining bolt
and ground strap.
Fig. 85 Oil Pump and Primary Timing Chain
Tensioner Tightening Sequence
Fig. 86 INTAKE MANIFOLD
1 - THROTTLE BODY
2 - INTAKE MANIFOLD
3 - INTAKE PORT GASKETS
9 - 68 ENGINE - 3.7LKJ
OIL PUMP (Continued)