INFINITI QX4 2001 Factory Service Manual

Tool number
(Kent-Moore No.)
Tool nameDescription
(J-43926)
Refrigerant dye leak
detection kit
Kit includes:
(J-42220) UV lamp and
UV safety glasses
(J-41459) Refrigerant
dye injector
(J-41447) qty. 24
R-134a refrigerant dye
(J-43872) Refrigerant
dye cleaner
SHA437F
Power supply:
DC 12V (Battery terminal)
(J-42220)
Fluorescent dye leak
detectorUV lamp
SHA438F
Power supply: DC 12V (Battery terminal)
For checking refrigerant leak when fluorescent dye
is installed in A/C system.
Includes: UV lamp and UV safety glasses
UV safety glasses
(J-41447)
R134a Fluorescent Leak
Detection Dye (Box of
24, 1/4 ounce bottles)Dye
SHA439F
Application: For R-134a PAG oil
Container: 1/4 ounce (7.4 cc) bottle
(Includes self-adhesive dye identification labels for
affixing to vehicle after charging system with dye.)
(J-41459)
R134a Dye Injector
Use with J-41447, 1/4
ounce bottleDye injector
SHA440F
For injecting 1/4 ounce of Fluorescent Leak Detec-
tion Dye into A/C system.
(J-43872)
Dye cleaner
SHA441F
For cleaning dye spills.
(J-39183)
Manifold gauge set (with
hoses and couplers)
NT199
Identification:
IThe gauge face indicates R-134a.
Fitting size: Thread size
I1/2²-16 ACME
PREPARATION
HFC-134a (R-134a) Service Tools and Equipment (Cont'd)
HA-12

Tool number
(Kent-Moore No.)
Tool nameDescription
Service hoses
IHigh side hose
(J-39501-72)
ILow side hose
(J-39502-72)
IUtility hose
(J-39476-72)
NT201
Hose color:
ILow hose: Blue with black stripe
IHigh hose: Red with black stripe
IUtility hose: Yellow with black stripe or green
with black stripe
Hose fitting to gauge:
I1/2²-16 ACME
Service couplers
IHigh side coupler
(J-39500-20)
ILow side coupler
(J-39500-24)
NT202
Hose fitting to service hose:
IM14 x 1.5 fitting is optional or permanently
attached.
(J-39650)
Refrigerant weight scale
NT200
For measuring of refrigerant
Fitting size: Thread size
I1/2²-16 ACME
(J-39649)
Vacuum pump
(Including the isolator
valve)
NT203
Capacity:
IAir displacement: 4 CFM
IMicron rating: 20 microns
IOil capacity: 482 g (17 oz)
Fitting size: Thread size
I1/2²-16 ACME
COMMERCIAL SERVICE TOOLNBHA0009S01
Tool name Description
Refrigerant identifier
equipment
NT765
For checking refrigerant purity and system con-
tamination
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PREPARATION
HFC-134a (R-134a) Service Tools and Equipment (Cont'd)
HA-13

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

V-6 Variable Displacement Compressor
GENERAL INFORMATION=NBHA00861. The V-6 variable compressor differs from previous units. The vent temperatures of the V-6 variable com-
press do not drop too far below 5ÉC (41ÉF) when:
Ievaporator intake air temperature is less than 20ÉC (68ÉF)
Iengine is running at speeds less than 1,500 rpm.
This is because the V-6 compressor provides a means of ªcapacityº control.
2. The V-6 variable compressor provides refrigerant control under varying conditions. During cold winters, it
may not produce high refrigerant pressure discharge (compared to previous units) when used with air
conditioning systems.
3. A ªclankingº sound may occasionally be heard during refrigerant charge. The sound indicates that the tilt
angle of the swash plate has changed and is not a problem.
4. For air conditioning systems with the V-6 compressor, the clutch remains engaged unless: the system main
switch, fan switch or ignition switch is turned OFF. When ambient (outside) temperatures are low or when
the amount of refrigerant is insufficient, the clutch is disengaged to protect the compressor.
5. A constant range of suction pressure is maintained when engine speed is greater than a certain value. It
normally ranges from 147 to 177 kPa (1.5 to 1.8 kg/cm
2, 21 to 26 psi) under varying conditions.
In previous compressors, however, suction pressure was reduced with increases in engine speed.
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DESCRIPTION
V-6 Variable Displacement Compressor
HA-15

DESCRIPTION=NBHA0087GeneralNBHA0087S01The variable compressor is basically a swash plate type that changes piston stroke in response to the required
cooling capacity.
The tilt of the swash plate allows the piston's stroke to change so that refrigerant discharge can be continu-
ously changed from 14.5 to 184 cm
3(0.885 to 11.228 cu in).
RHA037DD
DESCRIPTION
V-6 Variable Displacement Compressor (Cont'd)
HA-16

Operation=NBHA0087S021. Operation Control ValveNBHA0087S0201Operation control valve is located in the suction port (low-pressure) side, and opens or closes in response to
changes in refrigerant suction pressure.
Operation of the valve controls the internal pressure of the crankcase.
The angle of the swash plate is controlled between the crankcase's internal pressure and the piston cylinder
pressure.
2. Maximum Cooling
NBHA0087S0202Refrigerant pressure on the low-pressure side increases with an increase in heat loads.
When this occurs, the control valve's bellows compress to open the low-pressure side valve and close the
high-pressure side valve.
This causes the following pressure changes:
Ithe crankcase's internal pressure to equal the pressure on the low-pressure side;
Ithe cylinder's internal pressure to be greater than the crankcase's internal pressure.
Under this condition, the swash plate is set to the maximum stroke position.
RHA473C
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DESCRIPTION
V-6 Variable Displacement Compressor (Cont'd)
HA-17

3. Capacity Control=NBHA0087S0203IRefrigerant pressure on suction side is low during high speed driving or when ambient or interior tempera-
ture is low.
IThe bellows expands when refrigerant pressure on the suction pressure side drops below approximately
177 kPa (1.8 kg/cm
2, 26 psi).
Since suction pressure is low, it makes the suction port close and the discharge port open. Thus, crank-
case pressure becomes high as high pressure enters the crankcase.
IThe force acts around the journal pin near the swash plate, and is generated by the pressure difference
before and behind the piston.
The drive lug and journal pin are located where the piston generates the highest pressure. Piston pres-
sure is between suction pressure Ps and discharge pressure Pd, which is near suction pressure Ps. If
crankcase pressure Pc rises due to capacity control, the force around the journal pin makes the swash
plate angle decrease and also the piston stroke decrease. In other words, crankcase pressure increase
triggers pressure difference between the piston and the crankcase. The pressure difference changes the
angle of the swash plate.
RHA474C
DESCRIPTION
V-6 Variable Displacement Compressor (Cont'd)
HA-18

Component LayoutNBHA0012
RHA451G
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DESCRIPTION
Component Layout
HA-19

IntroductionNBHA0013AIR CONDITIONER LAN SYSTEM OVERVIEW CONTROL SYSTEMNBHA0013S01The LAN system consists of auto amp., air mix door motor and mode door motor.
A configuration of these components is shown in the diagram below.
RHA439G
FeaturesNBHA0014SYSTEM CONSTRUCTION (LAN)NBHA0014S08A small network is constructed between the auto amplifier, air mix door motor and mode door motor. The auto
amplifier and motors are connected by data transmission lines and motor power supply lines. The LAN net-
work is built through the ground circuits of the two motors.
Addresses, motor opening angle signals, motor stop signals and error checking messages are all transmitted
through the data transmission lines connecting the auto amplifier and two motors.
The following functions are contained in LCUs built into the air mix door motor and the mode door motor.
IAddress
IMotor opening angle signals
IData transmission
IMotor stop and drive decision
IOpening angle sensor (PBR function)
IComparison
IDecision (Auto amplifier indicated value and motor opening angle comparison)
RHA440GA
OperationNBHA0014S0801The auto amplifier receives data from each of the sensors. The amplifier sends air mix door and mode door
opening angle data to the air mix door motor LCU and mode door motor LCU.
The air mix door motor and mode door motor read their respective signals according to the address signal.
Opening angle indication signals received from the auto amplifier and each of the motor position sensors are
compared by the LCUs in each motor with the existing decision and opening angles. Subsequently, HOT/
COLD or DEFROST/VENT operation is selected. The new selection data is returned to the auto amplifier.
DESCRIPTION
Introduction
HA-20

RHA441GA
Transmission Data and Transmission OrderNBHA0014S0802Amplifier data is transmitted consecutively to each of the door motors following the form shown in figure below.
Start: Initial compulsory signal sent to each of the door motors.
Address: Data sent from the auto amplifier is selected according to data-based decisions made by the air mix
door motor and mode door motor.
If the addresses are identical, the opening angle data and error check signals are received by the door motor
LCUs. The LCUs then make the appropriate error decision. If the opening angle data is normal, door control
begins.
If an error exists, the received data is rejected and corrected data received. Finally, door control is based upon
the corrected opening angle data.
Opening angle: Data that shows the indicated door opening angle of each door motor.
Error check: Procedure by which sent and received data is checked for errors. Error data is then compiled.
The error check prevents corrupted data from being used by the air mix door motor and mode door motor.
Error data can be related to the following problems.
IAbnormal electrical frequency
IPoor electrical connections
ISignal leakage from transmission lines
ISignal level fluctuation
Stop signal: At the end of each transmission, a stop operation, in-operation, or internal problem message is
delivered to the auto amplifier. This completes one data transmission and control cycle.
RHA442G
Air Mix Door Control (Automatic Temperature Control)NBHA0014S0803The air mix door is automatically controlled so that in-vehicle temperature is maintained at a predetermined
value by: The temperature setting, ambient temperature, in-vehicle temperature and amount of sunload.
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DESCRIPTION
Features (Cont'd)
HA-21