2001 INFINITI QX4 maintenance

Basic InspectionNBEC0038Precaution:
Perform Basic Inspection without electrical or mechanical
loads applied;
IHeadlamp switch is OFF,
IAir conditioner switch is OFF,
IRear window defogger switch is OFF,
ISteering wheel is in the straight-ahead position, etc.
1 INSPECTION START
1. Check service records for any recent repairs that may indicate a related problem, or a current need for scheduled
maintenance.
2. Open engine hood and check the following:
IHarness connectors for improper connections
IVacuum hoses for splits, kinks and improper connections
IWiring for improper connections, pinches and cuts
IAir cleaner clogging
IHoses and ducts for leaks
SEF983U
©GO TO 2.
2 CHECK THROTTLE OPENER OPERATION-I
Confirm that there is a clearance between throttle drum and stopper.
SEF950Y
OK or NG
OK©GO TO 4.
NG©GO TO 3.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Basic Inspection
EC-101

Main 12 Causes of OverheatingNBEC0615
Engine Step Inspection item Equipment Standard Reference page
OFF 1IBlocked radiator
IBlocked condenser
IBlocked radiator grille
IBlocked bumperIVisual No blocking Ð
2ICoolant mixtureICoolant tester 50 - 50% coolant mixture See MA-11, ªRECOM-
MENDED FLUIDS AND
LUBRICANTSº.
3ICoolant levelIVisual Coolant up to MAX level
in reservoir tank and
radiator filler neckSee MA-14, ªChanging
Engine Coolantº.
4IRadiator capIPressure tester 59 - 98 kPa
(0.6 - 1.0 kg/cm
2,9-14
psi) (Limit)See LC-11, ªSystem
Checkº.
ON*
25ICoolant leaksIVisual No leaks See LC-11, ªSystem
Checkº.
ON*
26IThermostatITouch the upper and
lower radiator hosesBoth hoses should be
hotSee LC-16, ªThermostatº
and LC-19, ªRadiatorº.
ON*
17*5ICooling fanICONSULT-II Operating See trouble diagnosis for
DTC P0217 (EC-314).
OFF 8ICombustion gas leakIColor checker chemi-
cal tester 4 Gas ana-
lyzerNegative Ð
ON*
39ICoolant temperature
gaugeIVisual Gauge less than 3/4
when drivingÐ
ICoolant overflow to
reservoir tankIVisual No overflow during driv-
ing and idlingSee MA-14, ªChanging
Engine Coolantº.
OFF*
410ICoolant return from
reservoir tank to radia-
torIVisual Should be initial level in
reservoir tankSee MA-13, ªENGINE
MAINTENANCEº.
OFF 11ICylinder headIStraight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)See EM-42, ªInspectionº.
12ICylinder block and pis-
tonsIVisual No scuffing on cylinder
walls or pistonSee EM-63, ªInspectionº.
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
*5: Cooling fan is not applied to this vehicle.
For more information, refer to LC-24, ªOVERHEATING CAUSE ANALYSISº.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0217 COOLANT OVERTEMPERATURE ENRICHMENT PROTECTION
Main 12 Causes of Overheating
EC-319

5 CHECK IGNITION SPARK
1. Disconnect ignition wire from spark plug.
2. Connect a known good spark plug to the ignition wire.
3. Place end of spark plug against a suitable ground and crank engine.
4. Check for spark.
SEF575Q
OK or NG
OK©GO TO 6.
NG©Check ignition coil, power transistor and their circuits. Refer to ªDTC P1320 IGNITION
SIGNALº, EC-499
6 CHECK SPARK PLUGS
Remove the spark plugs and check for fouling, etc.
SEF156I
OK or NG
OK©GO TO 7.
NG©Repair or replace spark plug(s) with standard type one(s). For spark plug type, refer to
MA-13, ªENGINE MAINTENANCEº.
7 CHECK COMPRESSION PRESSURE
Check compression pressure. Refer to EM-14, ªMeasurement of Compression Pressureº.
Standard:
1,275 kPa (13.0 kg/cm
2, 185 psi)/300 rpm
Minimum:
981 kPa (10.0 kg/cm
2, 142 psi)/300 rpm
Difference between each cylinder:
98 kPa (1.0 kg/cm
2, 14 psi)/300 rpm
OK or NG
OK©GO TO 8.
NG©Check pistons, piston rings, valves, valve seats and cylinder head gaskets.
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0300 - P0306 NO.6-1CYLINDER MISFIRE, MULTIPLE CYLINDER
MISFIRE
Diagnostic Procedure (Cont'd)
EC-323

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBEL0001The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of side air bag module (located in the outer side of front seat),
satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring harness,
warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
ITo avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be performed
by an authorized INFINITI dealer.
IImproper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
Wiring Diagrams and Trouble DiagnosisNBEL0002When you read wiring diagrams, refer to the following:
IGI-11, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº for power distribution circuit
When you perform trouble diagnosis, refer to the following:
IGI-35, ªHOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSESº
IGI-24, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
Check for any Service bulletins before servicing the vehicle.
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
EL-4

PrecautionsNBGI0001Observe the following precautions to ensure safe and proper
servicing. These precautions are not described in each indi-
vidual section.
SGI646
PRECAUTIONS FOR SUPPLEMENTAL RESTRAINT
SYSTEM (SRS) ªAIR BAGº AND ªSEAT BELT
PRE-TENSIONERº
NBGI0001S01The Supplemental Restraint System such as ªAIR BAGº and ªSEAT
BELT PRE-TENSIONERº used along with a seat belt, helps to
reduce the risk or severity of injury to the driver and front passen-
ger for certain types of collision. The SRS system composition
which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag
module (located in the center of the steering wheel), front pas-
senger air bag module (located on the instrument panel on
passenger side), seat belt pre-tensioners, a diagnosis sensor
unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of side air bag
module (located in the outer side of front seat), satellite sensor,
diagnosis sensor unit (one of components of air bags for a
frontal collision), wiring harness, warning lamp (one of compo-
nents of air bags for a frontal collision).
Information necessary to service the system safely is included in
theRS sectionof this Service Manual.
WARNING:
ITo avoid rendering the SRS inoperative, which could
increase the risk of personal injury or death in the event
of a collision which would result in air bag inflation, all
maintenance must be performed by an authorized INFINITI
dealer.
IImproper maintenance, including incorrect removal and
installation of the SRS, can lead to personal injury caused
by unintentional activation of the system. For removal of
Spiral Cable and Air Bag Module, see the RS section.
IDo not use electrical test equipment on any circuit related
to the SRS unless instructed to in this Service Manual.
Spiral cable and wiring harnesses covered with yellow
insulation tape either just before the harness connectors
or for the complete harness are related to the SRS.
PRECAUTIONS FOR IVIS (INFINITI VEHICLE
IMMOBILIZER SYSTEM Ð NATS)
NBGI0001S08IVIS (NATS) will immobilize the engine if someone tries to start it
without the registered key of IVIS (NATS).
Both of the originally supplied ignition key IDs have been IVIS
(NATS) registered.
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
PRECAUTIONS
Precautions
GI-3

HEATER &
AIR CONDITIONER
SECTION
HA
CONTENTS
PRECAUTIONS...............................................................2
Supplemental Restraint System (SRS)²AIR
BAG²and²SEAT BELT PRE-TENSIONER²...............2
Precautions for Working with HFC-134a (R-134a) .....2
General Refrigerant Precautions .................................3
Precautions for Leak Detection Dye............................3
Identification .................................................................4
Precautions for Refrigerant Connection ......................4
Precautions for Servicing Compressor ........................6
Precautions for Service Equipment .............................7
Wiring Diagrams and Trouble Diagnoses....................9
PREPARATION.............................................................10
Special Service Tools ................................................10
HFC-134a (R-134a) Service Tools and
Equipment .................................................................. 11
DESCRIPTION...............................................................14
Refrigeration System .................................................14
V-6 Variable Displacement Compressor....................15
Component Layout ....................................................19
Introduction ................................................................20
Features .....................................................................20
Overview of Control System ......................................23
Control Operation ......................................................23
Discharge Air Flow.....................................................25
System Description ....................................................26
TROUBLE DIAGNOSES................................................27
Component Location..................................................27
Circuit Diagram (Without Navigation System) ...........30
Wiring Diagram - A/C, A - (Without Navigation
System) ......................................................................31
Circuit Diagram (With Navigation System) ................35
Wiring Diagram - A/C, A - (With Navigation
System) ......................................................................36
Auto Amp. Terminals and Reference Value...............40
Self-diagnosis ............................................................44
How to Perform Trouble Diagnoses for Quick
and Accurate Repair ..................................................65Operational Check .....................................................66
A/C System ................................................................71
Mode Door Motor.......................................................75
Air Mix Door Motor ....................................................82
Intake Door Motor ......................................................87
Blower Motor..............................................................95
Magnet Clutch..........................................................104
Insufficient Cooling .................................................. 112
Insufficient Heating ..................................................121
Noise ........................................................................123
Self-diagnosis ..........................................................124
Memory Function .....................................................126
ECON (ECONOMY) Mode ......................................128
Ambient Sensor Circuit ............................................129
In-vehicle Sensor Circuit..........................................132
Sunload Sensor Circuit ............................................135
Intake Sensor Circuit ...............................................139
Air Mix Door Motor PBR Circuit ..............................141
Multiplex Communication Circuit .............................142
SERVICE PROCEDURE..............................................144
HFC-134a (R-134a) Service Procedure ..................144
Maintenance of Lubricant Quantity in
Compressor .............................................................146
Compressor .............................................................149
Compressor Clutch ..................................................150
Refrigerant Lines .....................................................154
Belt ...........................................................................159
Ventilation Air Filter ..................................................159
SERVICE DATA AND SPECIFICATIONS (SDS).......160
Compressor .............................................................160
Lubricant ..................................................................160
Refrigerant ...............................................................160
Engine Idling Speed (When A/C is ON) ..................160
Belt Tension .............................................................160
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBHA0001The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of front side air bag module (located in the outer side of front
seat), satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring
harness, warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
ITo avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be performed
by an authorized INFINITI dealer.
IImproper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
Precautions for Working with HFC-134a
(R-134a)
NBHA0002WARNING:
ICFC-12 (R-12) refrigerant and HFC-134a (R-134a) refrigerant are not compatible. If the refrigerants
are mixed and compressor failure is likely to occur, refer to ªCONTAMINATED REFRIGERANTº
below. To determine the purity of HFC-134a (R-134a) in the vehicle and recovery tank, use Refrig-
erant Recovery/Recycling Recharging equipment (ACR4) (J-39500-INF) and Refrigerant Identifier.
IUse only specified lubricant for the HFC-134a (R-134a) A/C system and HFC-134a (R-134a) compo-
nents. If lubricant other than that specified is used, compressor failure is likely to occur.
IThe specified HFC-134a (R-134a) lubricant rapidly absorbs moisture from the atmosphere. The fol-
lowing handling precautions must be observed:
a) When removing refrigerant components from a vehicle, immediately cap (seal) the component to
minimize the entry of moisture from the atmosphere.
b) When installing refrigerant components to a vehicle, do not remove the caps (unseal) until just
before connecting the components. Connect all refrigerant loop components as quickly as pos-
sible to minimize the entry of moisture into system.
c) Only use the specified lubricant from a sealed container. Immediately reseal containers of lubri-
cant. Without proper sealing, lubricant will become moisture saturated and should not be used.
d) Avoid breathing A/C refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose and
throat. Remove R-134a from the A/C system, using certified service equipment meeting require-
ments of SAE J2210 (R-134a recycling equipment), or J2209 (R-134a recovery equipment). If acci-
dental system discharge occurs, ventilate work area before resuming service. Additional health and
safety information may be obtained from refrigerant and lubricant manufacturers.
e) Do not allow lubricant (Nissan A/C System Oil Type S) to come in contact with styrofoam parts.
Damage may result.
CONTAMINATED REFRIGERANTNBHA0002S01If a refrigerant other than pure R-134a is identified in a vehicle, your options are:
IExplain to the customer that environmental regulations prohibit the release of contaminated refrigerant into
the atmosphere.
IExplain that recovery of the contaminated refrigerant could damage your service equipment and refriger-
ant supply.
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
HA-2

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