2001 INFINITI QX4 engine

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

ISuggest the customer return the vehicle to the location of previous service where the contamination may
have occurred.
IIf you choose to perform the repair, recover the refrigerant using onlydedicated equipment and con-
tainers. Do not recover contaminated refrigerant into your existing service equipment.If your facil-
ity does not have dedicated recovery equipment, you may contact a local refrigerant product retailer for
available service. This refrigerant must be disposed of in accordance with all federal and local regulations.
In addition, replacement of all refrigerant system components on the vehicle is recommended.
IIf the vehicle is within the warranty period, the air conditioner warranty is void. Please contact Nissan
Customer Affairs for further assistance.
General Refrigerant PrecautionsNBHA0003WARNING:
IDo not release refrigerant into the air. Use approved recovery/recycling equipment to capture the
refrigerant every time an air conditioning system is discharged.
IAlways wear eye and hand protection (goggles and gloves) when working with any refrigerant or
air conditioning system.
IDo not store or heat refrigerant containers above 52ÉC (125ÉF).
IDo not heat a refrigerant container with an open flame; if container warming is required, place the
bottom of the container in a warm pail of water.
IDo not intentionally drop, puncture, or incinerate refrigerant containers.
IKeep refrigerant away from open flames: poisonous gas will be produced if refrigerant burns.
IRefrigerant will displace oxygen, therefore be certain to work in well ventilated areas to prevent
suffocation.
IDo not pressure test or leak test HFC-134a (R-134a) service equipment and/or vehicle air condi-
tioning systems with compressed air during repair. Some mixtures of air and R-134a have been
shown to be combustible at elevated pressures. These mixtures, if ignited, may cause injury or
property damage. Additional health and safety information may be obtained from refrigerant manu-
facturers.
Precautions for Leak Detection DyeNBHA0111IThe A/C system contains a fluorescent leak detection dye used for locating refrigerant leaks. An ultravio-
let (UV) lamp is required to illuminate the dye when inspecting for leaks.
IAlways wear fluorescence enhancing UV safety glasses to protect your eyes and enhance the visibility of
the fluorescent dye.
IThe fluorescent dye leak detector is not a replacement for an electronic refrigerant leak detector. The
fluorescent dye leak detector should be used in conjunction with an electronic refrigerant leak detector to
(J-41995) pin-point refrigerant leaks.
IFor your safety and your Customer's satisfaction, read and follow all manufacture's operating instructions
and precautions prior to performing the work.
IA compressor shaft seal should not be repaired because of dye seepage. The compressor shaft seal
should only be repaired after confirming the leak with an electronic refrigerant leak detector (J-41995).
IAlways remove and dye from the leak area after repairs are complete to avoid a misdiagnosis during a
future service.
IDo not allow dye to come into contact with painted body panels or interior components. If dye is spilled,
clean immediately with the approved dye cleaner. Fluorescent dye left on a surface for an extended period
of time cannot be removed.
IDo not spray the fluorescent dye cleaning agent on hot surfaces (engine exhaust manifold, etc.).
IDo not use more than one refrigerant dye bottle (1/4 ounce /7.4 cc) per A/C system.
ILeak detection dyes for R-134a and R12 A/C systems are different. Do not use R-134a leak detection dye
in R-12 A/C system or R-12 leak detector dye in R-134a A/C systems or A/C system damage may result.
IThe fluorescent properties of the dye will remain for over three (3) years unless a compressor failure
occurs.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
PRECAUTIONS
Precautions for Working with HFC-134a (R-134a) (Cont'd)
HA-3

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

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.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
DESCRIPTION
V-6 Variable Displacement Compressor
HA-15

Fan Speed ControlNBHA0014S0804Blower speed is automatically controlled based on temperature setting, ambient temperature, in-vehicle
temperature, intake temperature, amount of sunload and air mix door position.
With FAN switch set to ªAUTOº, the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower motor operation is delayed to prevent cool air from flow-
ing.
Intake Door ControlNBHA0014S0805The intake doors are automatically controlled by: The temperature setting, ambient temperature, in-vehicle
temperature, intake temperature, amount of sunload and ON-OFF operation of the compressor.
Outlet Door ControlNBHA0014S0806The outlet door is automatically controlled by: The temperature setting, ambient temperature, in-vehicle
temperature, intake temperature and amount of sunload.
Magnet Clutch ControlNBHA0014S0807The ECM controls compressor operation using input signals from the throttle position sensor and auto ampli-
fier.
Self-diagnostic SystemNBHA0014S0808The self-diagnostic system is built into the auto amplifier (LCU) to quickly locate the cause of problems.
DESCRIPTION
Features (Cont'd)
HA-22

Component LocationNBHA0033ENGINE COMPARTMENTNBHA0033S01
SHA281FA
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Component Location
HA-27

TERMINAL
NO.ITEM CONDITIONVoltage
V
13 Thermal transmitter
Engine coolant
temperatureApproximately 30ÉC (86ÉF) Approximately 9.4
Approximately 55ÉC (131ÉF) Approximately 6.5
Approximately 100ÉC
(212ÉF)Approximately 2.4
14 Ground (for Canada) Ð Approximately 0
16 A/C LAN signal Ð Approximately 5.5
18 Intake door position switch Intake door position20% FRE or RECIRCULA-
TIONApproximately 0
FRESH Approximately 4.6
19 Intake door position switch Intake door positionRECIRCULATION or
FRESHApproximately 0
20% FRE Approximately 4.6
21Power supply for mode door
motor and air mix door motorÐ Approximately 12
22 Compressor ON signal
CompressorON Approximately 0
OFF Approximately 4.6
24 Power supply for illumination
Lighting switchOFF Approximately 0
1st Approximately 12
25 Illumination ground Ð Approximately 0
26 Power supply for BAT
Ð BATTERY VOLTAGE
27 Power supply for IGN
Ð Approximately 12
28Power supply for intake door
motorIntake door positionFRESH Approximately 12
RECIRC Approximately 0
32 Ground Ð Approximately 0
33 Power source for A/C Ignition voltage feed back Approximately 12
34 Blower motor feed back Fan speed: Low Approximately7-10
35Fan control AMP. control sig-
nalFan speedLow, Middle low or Middle
highApproximately 2.5 -
3.0
High Approximately9-10
36Power supply for intake door
motorIntake door positionFRESH Approximately 0
RECIRC Approximately 12
With Navigation SystemNBHA0036S0202
TERMINAL
NO.ITEM CONDITIONVoltage
V
1 Intake sensor Ð Ð
2 Ambient sensor Ð Ð
3 In-vehicle sensor Ð Ð
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
SC
EL
IDX
TROUBLE DIAGNOSES
Auto Amp. Terminals and Reference Value (Cont'd)
HA-41

TERMINAL
NO.ITEM CONDITIONVoltage
V
6 Intake door position switch
Intake door positionRECIRCULATION Approximately 4.6
FRESH or 20% FRESH Approximately 0
7Multiplex communication sig-
nal
(AMP,NAVI)ÐÐ
8Multiplex communication sig-
nal
(NAVI,AMP)ÐÐ
9 Sensor ground
Ð Approximately 0
10 Sunload sensor Ð Ð
11 Thermal transmitter
Engine coolant
temperatureApproximately 30ÉC (86ÉF) Approximately 9.4
Approximately 55ÉC (131ÉF) Approximately 6.5
Approximately 100ÉC
(212ÉF)Approximately 2.4
Approximately 110ÉC
(230ÉF)Approximately 1.9
14 A/C LAN signal Ð Approximately 5.5
17 ECM signalCompressor: ON Approximately 0
Compressor: OFF Approximately 4.6
18 Intake door position switch Intake door positionFRESH Approximately 4.6
RECIRCULATION or 20%
FRESHApproximately 0
19 Intake door position switch Intake door position20% FRESH Approximately 4.6
RECIRCULATION or
FRESHApproximately 0
20Multiplex communication sig-
nal (CLK)ÐÐ
21 Power supply for door motor
Ð Approximately 12
22 Compressor ON signalCompressor: ON Approximately 0
Compressor: OFF Approximately 4.6
24 Power supply for BAT Ð BATTERY VOLTAGE
TROUBLE DIAGNOSES
Auto Amp. Terminals and Reference Value (Cont'd)
HA-42