2001 INFINITI QX4 INSTALLATION

ohmmeter, contact by a single strand of wire will give reading of 0
ohms. This would indicate a good circuit. When the circuit operates,
this single strand of wire is not able to carry the current. The single
strand will have a high resistance to the current. This will be picked
up as a slight voltage drop.
Unwanted resistance can be caused by many situations as follows:
IUndersized wiring (single strand example)
ICorrosion on switch contacts
ILoose wire connections or splices.
If repairs are needed always use wire that is of the same or larger
gauge.
Measuring Voltage Drop Ð Accumulated Method
1) Connect the voltmeter across the connector or part of the cir-
cuit you want to check. The positive lead of the voltmeter
should be closer to power and the negative lead closer to
ground.
2) Operate the circuit.
3) The voltmeter will indicate how many volts are being used to
ªpushº current through that part of the circuit.
Note in the illustration that there is an excessive 4.1 volt drop
between the battery and the bulb.
SGI974
Measuring Voltage Drop Ð Step by Step
The step by step method is most useful for isolating excessive
drops in low voltage systems (such as those in ªComputer Con-
trolled Systemsº).
Circuits in the ªComputer Controlled Systemº operate on very low
amperage.
The (Computer Controlled) system operations can be adversely
affected by any variation in resistance in the system. Such resis-
tance variation may be caused by poor connection, improper
installation, improper wire gauge or corrosion.
The step by step voltage drop test can identify a component or wire
with too much resistance.
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HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Circuit Inspection (Cont'd)
GI-31

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

SHA436F
IdentificationNBHA0112IDENTIFICATION LABEL FOR VEHICLENBHA0112S01Vehicles with factory installed fluorescent dye have this identifica-
tion label on the under side of hood.
NOTE:
Vehicles with factory installed fluorescent dye have a green label.
Vehicles without factory installed fluorescent dye have a blue label.
Precautions for Refrigerant ConnectionNBHA0004A new type refrigerant connection has been introduced to all refrigerant lines except the following location.
IExpansion valve to cooling unit
FEATURES OF NEW TYPE REFRIGERANT CONNECTIONNBHA0004S01IThe O-ring has been relocated. It has also been provided with a groove for proper installation. This elimi-
nates the chance of the O-ring being caught in, or damaged by, the mating part. The sealing direction of
the O-ring is now set vertically in relation to the contacting surface of the mating part to improve sealing
characteristics.
IThe reaction force of the O-ring will not occur in the direction that causes the joint to pull out, thereby
facilitating piping connections.
SHA815E
PRECAUTIONS
Identification
HA-4

Both High- and Low-pressure Sides are Too High.NBHA0032S01
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high.
AC359A
IPressure is reduced soon
after water is splashed on
condenser.Excessive refrigerant charge
in refrigeration cycleReduce refrigerant until
specified pressure is
obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cool-
ing performance
"
1. Condenser fins are
clogged.
2. Improper fan rotation of
cooling fanIClean condenser.
ICheck and repair cooling
fan as necessary.
ILow-pressure pipe is not
cold.
IWhen compressor is
stopped high-pressure
value quickly drops by
approximately 196 kPa (2
kg/cm
2, 28 psi). It then
decreases gradually there-
after.Poor heat exchange in con-
denser
(After compressor operation
stops, high pressure
decreases too slowly.)
"
Air in refrigeration cycleEvacuate repeatedly and
recharge system.
Engine tends to overheat. Engine cooling systems mal-
function.Check and repair each
engine cooling system.
IAn area of the low-pres-
sure pipe is colder than
areas near the evaporator
outlet.
IPlates are sometimes cov-
ered with frost.IExcessive liquid refrigerant
on low-pressure side
IExcessive refrigerant dis-
charge flow
IExpansion valve is open a
little compared with the
specification.
"
1. Improper thermal valve
installation
2. Improper expansion valve
adjustmentReplace expansion valve.
High-pressure Side is Too High and Low-pressure Side is Too Low.NBHA0032S02
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
AC360A
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts
located between compressor
and condenser are clogged
or crushed.ICheck and repair or
replace malfunctioning
parts.
ICheck lubricant for con-
tamination.
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TROUBLE DIAGNOSES
Insufficient Cooling (Cont'd)
HA-117

RHA065DD
Compressor
REMOVAL AND INSTALLATIONNBHA0072
RHA892H
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SERVICE PROCEDURE
Maintenance of Lubricant Quantity in Compressor (Cont'd)
HA-149

RHA138E
IRemove the snap ring using external snap ring pliers.
RHA139E
IPulley removal
Position the center pulley puller on the end of the drive shaft,
and remove the pulley assembly using any commercially avail-
able pulley puller.
To prevent the pulley groove from being deformed, the
puller claws should be positioned onto the edge of the
pulley assembly.
RHA125F
IRemove the field coil harness clip using a pair of pliers.
RHA145E
IRemove the snap ring using external snap ring pliers.
RHA126F
INSPECTIONNBHA0075Clutch DiscNBHA0075S01If the contact surface shows signs of damage due to excessive
heat, replace clutch disc and pulley.
PulleyNBHA0075S02Check the appearance of the pulley assembly. If the contact sur-
face of pulley shows signs of excessive grooving, replace clutch
disc and pulley. The contact surfaces of the pulley assembly should
be cleaned with a suitable solvent before reinstallation.
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SERVICE PROCEDURE
Compressor Clutch (Cont'd)
HA-151

CoilNBHA0075S03Check coil for loose connection or cracked insulation.
RHA142E
INSTALLATIONNBHA0076IInstall the field coil.
Be sure to align the coil's pin with the hole in the com-
pressor's front head.
IInstall the field coil harness clip using a screwdriver.
RHA143EA
IInstall the pulley assembly using the installer and a hand
press, and then install the snap ring using snap ring pliers.
RHA127F
IInstall the clutch disc on the drive shaft, together with the
original shim(s). Press the clutch disc down by hand.
RHA086E
IUsing the holder to prevent clutch disc rotation, tighten the bolt
to 14 N´m (1.4 kg-m, 10 ft-lb) torque.
After tightening the bolt, check that the pulley rotates
smoothly.
SERVICE PROCEDURE
Compressor Clutch (Cont'd)
HA-152

Refrigerant Lines
REMOVAL AND INSTALLATION=NBHA0077IRefer to page HA-4 regarding ªPrecautions for Refrigerant Connectionº.
RHA838H
SERVICE PROCEDURE
Refrigerant Lines
HA-154