2001 INFINITI QX4 low oil pressure

IClean all disassembled parts in the designated liquid or solvent
prior to inspection or assembly.
IReplace oil seals, gaskets, packings, O-rings, locking washers,
cotter pins, self-locking nuts, etc. with new ones.
IReplace inner and outer races of tapered roller bearings and
needle bearings as a set.
IArrange the disassembled parts in accordance with their
assembled locations and sequence.
IDo not touch the terminals of electrical components which use
microcomputers (such as ECMs).
Static electricity may damage internal electronic components.
IAfter disconnecting vacuum or air hoses, attach a tag to indi-
cate the proper connection.
IUse only the fluids and lubricants specified in this manual.
IUse approved bonding agent, sealants or their equivalents
when required.
IUse tools and recommended special tools where specified for
safe and efficient service repairs.
IWhen repairing the fuel, oil, water, vacuum or exhaust
systems, check all affected lines for leaks.
IDispose of drained oil or the solvent used for cleaning parts in
an appropriate manner.
WARNING:
To prevent ECM from storing the diagnostic trouble codes, do
not carelessly disconnect the harness connectors which are
related to the engine control system and TCM (Transmission
Control Module) system. The connectors should be discon-
nected only when working according to the WORK FLOW of
TROUBLE DIAGNOSES in EC and AT sections.
SGI787
PRECAUTIONS FOR MULTIPORT FUEL INJECTION
SYSTEM OR ENGINE CONTROL SYSTEM
NBGI0001S03IBefore connecting or disconnecting any harness connector for
the multiport fuel injection system or ECM (Engine Control
Module):
Turn ignition switch to OFF position.
Disconnect negative battery terminal.
Otherwise, there may be damage to ECM.
IBefore disconnecting pressurized fuel line from fuel pump to
injectors, be sure to release fuel pressure.
IBe careful not to jar components such as ECM and mass air
flow sensor.
PRECAUTIONS FOR THREE WAY CATALYSTNBGI0001S04If a large amount of unburned fuel flows into the catalyst, the cata-
lyst temperature will be excessively high. To prevent this, follow the
instructions below:
IUse unleaded gasoline only. Leaded gasoline will seriously
damage the three way catalyst.
IWhen checking for ignition spark or measuring engine
compression, make tests quickly and only when necessary.
IDo not run engine when the fuel tank level is low, otherwise the
engine may misfire causing damage to the catalyst.
PRECAUTIONS
Precautions (Cont'd)
GI-6

CAUTION:
When replacing or cleaning refrigerant cycle components, observe the following.
IWhen the compressor is removed, store it in the same position as it is when mounted on the car.
Failure to do so will cause lubricant to enter the low pressure chamber.
IWhen connecting tubes, always use a torque wrench and a back-up wrench.
IAfter disconnecting tubes, immediately plug all openings to prevent entry of dirt and moisture.
IWhen installing an air conditioner in the vehicle, connect the pipes as the final stage of the opera-
tion. Do not remove the seal caps of pipes and other components until just before required for
connection.
IAllow components stored in cool areas to warm to working area temperature before removing seal
caps. This prevents condensation from forming inside A/C components.
IThoroughly remove moisture from the refrigeration system before charging the refrigerant.
IAlways replace used O-rings.
IWhen connecting tube, apply lubricant to circle of the O-rings shown in illustration. Be careful not
to apply lubricant to threaded portion.
Lubricant name: Nissan A/C System Oil Type S
Part number: KLH00-PAGS0
IO-ring must be closely attached to dented portion of tube.
IWhen replacing the O-ring, be careful not to damage O-ring and tube.
IConnect tube until you hear it click, then tighten the nut or bolt by hand until snug. Make sure that
the O-ring is installed to tube correctly.
IAfter connecting line, conduct leak test and make sure that there is no leakage from connections.
When the gas leaking point is found, disconnect that line and replace the O-ring. Then tighten
connections of seal seat to the specified torque.
RHA861F
Precautions for Servicing CompressorNBHA0005IPlug all openings to prevent moisture and foreign matter from entering.
IWhen the compressor is removed, store it in the same position as it is when mounted on the car.
IWhen replacing or repairing compressor, follow ªMaintenance of Lubricant Quantity in Compres-
sorº exactly. Refer to HA-146.
IKeep friction surfaces between clutch and pulley clean. If the surface is contaminated, with
lubricant, wipe it off by using a clean waste cloth moistened with thinner.
IAfter compressor service operation, turn the compressor shaft by hand more than five turns in
both directions. This will equally distribute lubricant inside the compressor. After the compressor
is installed, let the engine idle and operate the compressor for one hour.
IAfter replacing the compressor magnet clutch, apply voltage to the new one and check for normal
operation.
PRECAUTIONS
Precautions for Refrigerant Connection (Cont'd)
HA-6

Precautions for Service EquipmentNBHA0006RECOVERY/RECYCLING EQUIPMENTNBHA0006S01Be certain to follow the manufacturers instructions for machine
operation and machine maintenance. Never introduce any refriger-
ant other than that specified into the machine.
ELECTRONIC LEAK DETECTORNBHA0006S02Be certain to follow the manufacturer's instructions for tester opera-
tion and tester maintenance.
RHA270DA
VACUUM PUMPNBHA0006S03The lubricant contained inside the vacuum pump is not compatible
with the specified lubricant for HFC-134a (R-134a) A/C systems.
The vent side of the vacuum pump is exposed to atmospheric
pressure. So the vacuum pump lubricant may migrate out of the
pump into the service hose. This is possible when the pump is
switched off after evacuation (vacuuming) and hose is connected
to it.
To prevent this migration, use a manual valve placed near the
hose-to-pump connection, as follows.
IUsually vacuum pumps have a manual isolator valve as part
of the pump. Close this valve to isolate the service hose from
the pump.
IFor pumps without an isolator, use a hose equipped with a
manual shut-off valve near the pump end. Close the valve to
isolate the hose from the pump.
IIf the hose has an automatic shut off valve, disconnect the
hose from the pump. As long as the hose is connected, the
valve is open and lubricating oil may migrate.
Some one-way valves open when vacuum is applied and close
under a no vacuum condition. Such valves may restrict the pump's
ability to pull a deep vacuum and are not recommended.
SHA533D
MANIFOLD GAUGE SETNBHA0006S04Be certain that the gauge face indicates R-134a or 134a. Be sure
the gauge set has 1/2²-16 ACME threaded connections for service
hoses. Confirm the set has been used only with refrigerant HFC-
134a (R-134a) and specified lubricants.
RHA272D
SERVICE HOSESNBHA0006S05Be certain that the service hoses display the markings described
(colored hose with black stripe). All hoses must include positive
shut off devices (either manual or automatic) near the end of the
hoses opposite the manifold gauge.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
PRECAUTIONS
Precautions for Service Equipment
HA-7

Refrigeration System
REFRIGERATION CYCLENBHA0010Refrigerant FlowNBHA0010S01The refrigerant flows in the standard pattern, that is, through the compressor, the condenser, the liquid tank,
through the evaporator, and back to the compressor. The refrigerant evaporation through the evaporator coil
is controlled by an externally equalized expansion valve, located inside the evaporator case.
Freeze ProtectionNBHA0010S02Under normal operating conditions, when the A/C is switched on, the compressor runs continuously, and the
evaporator pressure, and therefore temperature, is controlled by the V-6 variable displacement compressor to
prevent freeze up.
Refrigerant System ProtectionNBHA0010S03Refrigerant Pressure SensorNBHA0010S0303The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure
sensor, located on the liquid tank. If the system pressure rises above, or falls below the specifications, the
refrigerant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the
ECM. ECM makes the A/C relay go OFF and stops the compressor when pressure on the high pressure side
detected by refrigerant pressure sensor is over about 2,746 kPa (28 kg/cm
2, 398 psi) or below about 177 kPa
(1.8 kg/cm2, 26 psi).
Pressure Relief Valve
NBHA0010S0302The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compres-
sor. When the pressure of refrigerant in the system increases to an abnormal level [more than 3,727 kPa (38
kg/cm
2, 540 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant
into the atmosphere.
RHA347H
DESCRIPTION
Refrigeration System
HA-14

Maintenance of Lubricant Quantity in
Compressor
NBHA0071The lubricant in the compressor circulates through the system with
the refrigerant. Add lubricant to compressor when replacing any
component or after a large gas leakage occurred. It is important to
maintain the specified amount.
If lubricant quantity is not maintained properly, the following mal-
functions may result:
ILack of lubricant: May lead to a seized compressor
IExcessive lubricant: Inadequate cooling (thermal exchange
interference)
LUBRICANTNBHA0071S01Name: Nissan A/C System Oil Type S
Part number: KLH00-PAGS0
CHECKING AND ADJUSTINGNBHA0071S02Adjust the lubricant quantity according to the test group shown
below.
1 CHECK LUBRICANT RETURN OPERATION
Can lubricant return operation be performed?
IA/C system works properly.
IThere is no evidence of a large amount of lubricant leakage.
YesorNo
Ye s©GO TO 2.
No©GO TO 3.
2 PERFORM LUBRICANT RETURN OPERATION, PROCEEDING AS FOLLOWS:
1. Start engine, and set the following conditions:
ITest condition
Engine speed: Idling to 1,200 rpm
A/C or AUTO switch: ON
Blower speed: Max. position
Temp. control: Optional [Set so that intake air temperature is 25 to 30ÉC (77 to 86ÉF).]
2.Next item is for V-5 or V-6 compressor. Connect the manifold gauge, and check that the high pressure side
pressure is 588 kPa (6 kg/cm
2, 85 psi) or higher.
If less than the reference level, attach a cover to the front face of the condenser to raise the pressure.
3. Perform lubricant return operation for about 10 minutes.
4. Stop engine.
CAUTION:
If excessive lubricant leakage is noted, do not perform the lubricant return operation.
OK©GO TO 3.
3 CHECK COMPRESSOR
Should the compressor be replaced?
YesorNo
Ye s©Go to ªLubricant Adjustment Procedure for Compressor Replacementº, (HA-148).
No©GO TO 4.
SERVICE PROCEDURE
Maintenance of Lubricant Quantity in Compressor
HA-146

5. When the A/C operating (compressor running), inject one
bottle (1/4 ounce /7.4 cc) of fluorescent dye through the low-
pressure service valve using dye injector tool J-41459 (refer to
the manufacture's operating instructions).
6. With the engine still running, disconnect the injector tool from
the service fitting.
CAUTION:
Be careful not to allow dye to spray or drip when disconnect-
ing the injector from the system.
NOTE:
If repairing the A/C system or replacing a component, pour the
dye directly into the open system connection and proceed
with the service procedures.
7. Operate the A/C system for a minimum of 20 minutes to mix
the dye with the system oil. Depending on the leak size, oper-
ating conditions and location of the leak, it may take from min-
utes to days for the dye to penetrate a leak and become visible.
SHA196FA
ELECTRONIC REFRIGERANT LEAK DETECTORNBHA0115Precautions for Handling Leak DetectorNBHA0115S01When performing a refrigerant leak check, use a J-41995 A/C leak
detector or equivalent. Ensure that the instrument is calibrated and
set properly per the operating instructions.
The leak detector is a delicate device. In order to use the leak
detector properly, read the operating instructions and perform any
specified maintenance.
SHA707EA
1. Position probe approximately 5 mm (3/16 in) away from point
to be checked.
SHA706E
2. When testing, circle each fitting completely with probe.
SERVICE PROCEDURE
Refrigerant Lines (Cont'd)
HA-156

A
AAC/V - Wiring diagram ...............................EC-425
ABS - Wiring diagram ....................................BR-37
ABS sensor rotor ........................................AX-6, 19
Absolute pressure sensor ............................EC-158
A/C air flow .....................................................HA-25
A/C component layout ....................................HA-19
A/C compressor clutch removal and
installation .................................................HA-150
A/C compressor precaution..............................HA-6
A/C compressor special service tool..............HA-10
A/C control operation (auto A/C) ....................HA-23
A/C diagnostic work flow (auto A/C) ..............HA-65
A/C HFC134a (R134a) system
precaution .....................................................HA-2
A/C HFC134a (R134a) system service
procedure ..................................................HA-144
A/C HFC134a (R134a) system service
tools.............................................................HA-11
A/C HFC134a system service equip-
ment precaution ............................................HA-7
A/C lubricant (R134a)...................................HA-146
A/C operational check ....................................HA-66
A/C performance chart .................................HA-116
A/C performance test diagnoses ..................HA-114
A/C relay .......................................................HA-110
A/C self-diagnoses (auto A/C)........................HA-44
A/C service data specification ......................HA-160
A/C system description (auto A/C) .................HA-23
A/C trouble diagnoses (auto A/C) ..................HA-27
A/C, A - Wiring diagram ...........................HA-31, 36
Accelerator control system ...............................FE-3
Accelerator wire adjustment .............................FE-3
Actuator lever (Transfer) ...............................TF-120
Air bag ............................................................RS-10
Air bag disposal..............................................RS-22
Air bag precautions ...........................................GI-3
Air bleeding for brake system ..........................BR-8
Air cleaner filter replacement .........................MA-17
Air conditioner cut control ..............................EC-31
Air flow meter - See Mass air flow
sensor .......................................................EC-150
Air mix door control linkage adjustment.........HA-85
Air mix. door motor ................................HA-82, 141
Air spoiler, rear................................................BT-35
All - mode 4WD system ..................................TF-10
Alternator ........................................................SC-28
Ambient sensor ............................................HA-129
Angular tightening application..........................EM-3
Antenna - See Power antenna .....................EL-169
Anti-lock brake system - Wiring
diagram .......................................................BR-37
AP/SEN - Wiring diagram ............................EC-160
ASCD (automatic speed control device) ......EL-221
ASCD - Wiring diagram ................................EL-225
A/T - Wiring diagram - AT - FTS ...................AT-107
A/T - Wiring diagram - AT - MAIN ...................AT-96
A/T - Wiring diagram - AT - PNP/SW............AT-101A/T - Wiring diagram - AT - VSS A/T ............AT-113
A/T control ....................................................EC-440
A/T diagnosis communication line................EC-603
A/T fluid temperature sensor .........................AT-110
A/T self-diagnoses...........................................AT-46
A/T shift lock system .....................................AT-265
A/T shift lock system - Wiring diagram .........AT-266
A/T trouble diagnoses .....................................AT-53
A/T Wiring diagram - AT - ENG SS...............AT-117
A/T Wiring diagram AT - 1ST ........................AT-123
A/T Wiring diagram AT - 2ND .......................AT-129
A/T Wiring diagram AT - 3RD .......................AT-135
A/T Wiring diagram AT - 4TH ........................AT-142
A/T Wiring diagram AT - BA/FTS ..................AT-192
A/T Wiring diagram AT - LPSV .....................AT-164
A/T Wiring diagram AT - NONDTC ...............AT-215
A/T Wiring diagram AT - OVRCSV ...............AT-187
A/T Wiring diagram AT - SSV/A ....................AT-169
A/T Wiring diagram AT - SSV/B ....................AT-173
A/T Wiring diagram AT - TCCSIG .................AT-156
A/T Wiring diagram AT - TCV .......................AT-150
A/T Wiring diagram AT - TPS........................AT-179
A/T Wiring diagram AT - VSSMTR................AT-199
AT/C - Wiring diagram ..................................EC-442
ATP switch.....................................................TF-112
ATP warning lamp .........................................TF-102
Audio .............................................................EL-160
AUDIO - Wiring diagram ...............................EL-162
Audio and A/C control removal and
installation - See Instrument panel .............BT-21
AUT/DP - Wiring diagram .............................EL-191
Auto air conditioner - Wiring diagram ......HA-31, 36
Automatic amplifier...................................HA-40, 72
Automatic drive positioner ............................EL-186
Automatic speed control system - See
ASCD ........................................................EL-221
Automatic transmission fluid
replacement ................................................MA-21
Automatic transmission number ......................GI-43
Auxiliary air control (AAC) valve ..................EC-422
Axle housing (rear) .........................................AX-19
B
Back door ........................................................BT-15
Back door opener - See Back door ................BT-15
Back door trim.................................................BT-34
Back-up lamp ..................................................EL-69
BACK/L - Wiring diagram................................EL-69
Ball joint (front) ...............................................SU-12
Base idle air volume initialiging......................EC-57
Basic inspection ...........................................EC-101
Battery ..............................................................SC-4
Battery/Starting/Charging System
Tester ................................................SC-7, 12, 21
Blower motor ..................................................HA-95
Body alignment ...............................................BT-57
Brake booster .................................................BR-19
Brake control valve (Proportioning
valve)...........................................................BR-11
ALPHABETICAL INDEX
IDX-2

E
ECM input/output signal ...............................EC-127
ECTS - Wiring diagram ........................EC-171, 189
Electric sun roof ............................................EL-173
Electrical diagnoses.........................................GI-24
Electrical ignition system ................................EC-30
Electrical unit ................................................Foldout
Electrical units location .................................EL-436
Engine compartment .......................................BT-58
Engine control circuit diagram........................EC-24
Engine control component parts
location .......................................................EC-20
Engine control module (ECM) ......................EC-444
Engine control system diagram and
chart ............................................................EC-25
Engine coolant temperature sensor
(ECTS) ..............................................EC-169, 187
Engine fail-safe system ................................EC-117
Engine oil filter replacement ..........................MA-18
Engine oil precautions .......................................GI-8
Engine oil replacement ..................................MA-18
Engine outer component parts ......................EM-10
Engine removal ..............................................EM-57
Engine room - See Engine
compartment................................................BT-58
Engine serial number ......................................GI-43
EVAP canister.................................................EC-33
EVAP canister purge volume control
solenoid valve.............................EC-32, 367, 541
EVAP canister vent control
valve .........................................EC-374, 553, 573
EVAP control system (small leak)
diagnosis ..................................EC-352, 394, 526
EVAP control system pressure sensor.........EC-381
EVAP control system purge flow moni-
toring diagnosis.........................................EC-561
EVAP vapor lines inspection ..........................MA-20
Evaporative emission (EVAP) system ............EC-32
Exhaust system ................................................FE-8
Exhaust system inspection ............................MA-21
Exterior ............................................................BT-35
F
4LO indicator lamp........................................TF-104
4WD shift indicator lamp.................................TF-98
4WD shift switch ............................................TF-111
4WD solenoid valve.......................................TF-111
4WD warning lamp .........................................TF-13
Fan control amp. ............................................HA-98
F/FOG - Wiring diagram .................................EL-72
Final drive disassembly ..................................PD-43
Final drive pre-inspection ...............................PD-43
Final drive removal and installation ...............PD-43
Finisher, interior - See Trim ............................BT-28
F/LID - Wiring diagram .................................EL-180
Fluid temperature sensor (A/T) .....................AT-110Fluids ..............................................................MA-11
Flywheel runout..............................................EM-70
FO2H-L - Wiring diagram .............................EC-243
FO2H-R - Wiring diagram ............................EC-242
Fog lamp, front................................................EL-70
Fog lamp, front, removal and
installation ...................................................BT-12
Forward clutch ...............................................AT-320
F/PUMP - Wiring diagram ............................EC-627
Freeze frame data ..........................................EC-60
FRO2LH - Wiring diagram ...........EC-197, 223, 235
FRO2RH - Wiring diagram...........EC-196, 222, 234
Front axle..........................................................AX-2
Front bumper ..................................................BT-12
Front case (Transfer) ....................................TF-133
Front combination lamp removal and
installation ...................................................BT-12
Front disc brake .............................................BR-22
Front door .......................................................BT-18
Front drive shaft (Transfer) ...........................TF-125
Front final drive disassembly (4WD) ..............PD-18
Front final drive pre-inspection (4WD) ...........PD-18
Front final drive removal and installa-
tion (4WD)...................................................PD-18
Front fog lamp.................................................EL-70
Front fog lamp removal and installation .........BT-12
Front heated oxygen sensor (HO2S)
(Left bank) ................EC-192, 202, 210, 218, 231
Front heated oxygen sensor (HO2S)
(Right bank) .............EC-192, 202, 210, 218, 231
Front heated oxygen sensor heater
(Left bank).................................................EC-240
Front heated oxygen sensor heater
(Right bank) ..............................................EC-240
Front revolution sensor (Transfer) ................TF-112
Front seat ........................................................BT-41
Front seat belt ..................................................RS-4
Front suspension ..............................................SU-2
Front washer .................................................EL-136
Front wiper ....................................................EL-136
Fuel cut control (at no load & high
engine speed) .............................................EC-32
Fuel filler lid.....................................................BT-15
Fuel filter replacement ...................................MA-16
Fuel gauge ......................................................EL-94
Fuel injection system (Left bank) .........EC-294, 302
Fuel injection system (Right bank) ......EC-294, 302
Fuel lid opener, electric.................................EL-180
Fuel line inspection ........................................MA-16
Fuel precautions ................................................GI-8
Fuel pressure check .......................................EC-39
Fuel pressure regulator ..................................EC-40
Fuel pressure release ....................................EC-39
Fuel pump ....................................................EC-625
Fuel system ......................................................FE-4
Fuel tank temperature sensor ......................EC-309
Fuel tank vacuum relief valve ........................EC-33
FUELLH - Wiring diagram....................EC-297, 305
FUELRH - Wiring diagram ...................EC-296, 304
Fuse ................................................................EL-16
Fuse block ....................................................Foldout
ALPHABETICAL INDEX
IDX-4