
ATC-1
AIR CONDITIONER
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CONTENTS
AUTOMATIC AIR CONDITIONER
SERVICE INFORMATION .. ..........................3
PRECAUTIONS .............................................. .....3
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
3
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect .....................................
3
Precaution for Procedure without Cowl Top Cover ......4
Precaution for Working with HFC-134a (R-134a) ......4
General Refrigerant Precaution ................................4
Precaution for Refrigerant Connection ......................5
Precaution for Service of Compressor ......................9
Precaution for Service Equipment .............................9
Precaution for Leak Detection Dye .........................11
PREPARATION ..................................................13
Special Service Tool ........................................... ....13
HFC-134a (R-134a) Service Tool and Equipment ....13
Commercial Service Tool ........................................16
REFRIGERATION SYSTEM ..............................17
Refrigerant Cycle ................................................ ....17
Refrigerant System Protection ................................17
V-6 Variable Displacement Compressor .................17
Component Part Location .......................................21
LUBRICANT ................................................... ....22
Maintenance of Lubricant Quantity in Compressor ....22
AIR CONDITIONER CONTROL .........................24
Description of Air Conditioner LAN Control Sys-
tem ...................................................................... ....
24
System Construction ...............................................24
Description of Control System .................................27
Control Operation ....................................................27
Fail-Safe Function ...................................................28
Discharge Air Flow ..................................................29
System Description .................................................30
CAN Communication System Description ...............30
TROUBLE DIAGNOSIS .....................................32
CONSULT-III Function ........................................ ....32
How to Perform Trouble Diagnosis for Quick and
Accurate Repair .......................................................
32
Component Parts and Harness Connector Loca-
tion ...........................................................................
34
Schematic ................................................................36
Wiring Diagram - A/C - ............................................37
Auto Amp. Terminal and Reference Value ..............42
Self-Diagnosis Function ...........................................43
Operational Check ...................................................50
Power Supply and Ground Circuit for Auto Amp .....52
LAN System Circuit .................................................54
Mode Door Motor Circuit .........................................57
Air Mix Door Motor Circuit .......................................59
Air Mix Door Motor PBR Circuit ...............................62
Intake Door Motor Circuit .........................................62
Blower Motor Circuit ................................................64
Magnet Clutch Circuit ..............................................69
Insufficient Cooling ..................................................75
Insufficient Heating ..................................................82
Noise .......................................................................83
Self-Diagnosis .........................................................84
Memory Function .....................................................85
Ambient Sensor Circuit ............................................86
In-vehicle Sensor Circuit ..........................................88
Sunload Sensor Circuit ............................................91
Intake Sensor Circuit ...............................................94
CONTROLLER ..................................................97
Removal and Installation of A/C and AV Switch ......97
AUTO AMP ........................................................98
Removal and Installation of Unified Meter and A/C
Amp .........................................................................
98
AMBIENT SENSOR ..........................................99
Removal and Installation .........................................99
IN-VEHICLE SENSOR ....................................100
Removal and Installation .......................................100
SUNLOAD SENSOR .......................................101
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ATC-2
Removal and Installation .......................................101
INTAKE SENSOR ............................................102
Removal and Installation ..................................... ..102
BLOWER UNIT ................................................103
Removal and Installation ..................................... ..103
Disassembly and Assembly ...................................104
BLOWER MOTOR ...........................................105
Removal and Installation ..................................... ..105
INTAKE DOOR MOTOR ..................................106
Removal and Installation ..................................... ..106
IN-CABIN MICROFILTER ................................107
Removal and Installation ..................................... ..107
HEATER & COOLING UNIT ASSEMBLY .......108
Removal and Installation ..................................... ..108
Disassembly and Assembly ...................................111
MODE DOOR MOTOR ....................................113
Removal and Installation ..................................... ..113
AIR MIX DOOR MOTOR ..................................114
Removal and Installation ..................................... ..114
HEATER CORE ...............................................115
Removal and Installation ..................................... ..115
DUCTS AND GRILLES ....................................116
Removal and Installation ..................................... ..116
REFRIGERANT LINES ....................................120
HFC-134a (R-134a) Service Procedure .............. ..120
Component .......................................................... .121
Removal and Installation of Compressor ..............123
Removal and Installation of Compressor Clutch ...125
Removal and Installation of Low-Pressure Flexi-
ble Hose ............................................................... .
128
Removal and Installation of High-pressure Flexi-
ble Hose ................................................................
129
Removal and Installation of Low-Pressure Pipe 1
(Engine Compartment) ..........................................
131
Removal and Installation of High-pressure Pipe 1
and 2 (Engine Compartment) ................................
132
Removal and Installation of Low-Pressure Pipe 2
and High-pressure Pipe 3 .....................................
133
Removal and Installation of Liquid Tank ...............134
Removal and Installation of Condenser ................135
Removal and Installation of Refrigerant Pressure
Sensor .................................................................. .
137
Removal and Installation of Evaporator ................137
Removal and Installation of Expansion Valve .......138
Checking of Refrigerant Leaks ............................. .138
Checking System for Leaks Using the Fluorescent
Leak Detector ........................................................
138
Dye Injection .........................................................139
Electrical Leak Detector ........................................139
SERVICE DATA AND SPECIFICATIONS
(SDS) ................................................................
142
Compressor ......................................................... .142
Lubricant ...............................................................142
Refrigerant ............................................................142
Engine Idling Speed ..............................................142
Belt Tension ..........................................................142
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ATC-18
< SERVICE INFORMATION >
REFRIGERATION SYSTEM
Evaporator intake air temperature is less than 20°C (68 °F).
Engine is running at speeds less than 1,500 rpm.
This is because the V-6 compressor prov ides a means of “capacity” control.
2. The V-6 variable compressor provides refrigerant c ontrol 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 “clanking” sound may occasionally be heard during re frigerant charge. The sound indicates that the tilt
angle of the wobble (swash) plate has changed and is not a malfunction.
4. For air conditioning systems with the V-6 compresso r, the clutch remains engaged unless: the system
main switch, fan switch or ignition switch is tur ned OFF. When ambient (outside) temperatures are low or
when the amount of refrigerant is insufficient, t he clutch is disengaged to protect the compressor.
DESCRIPTION
General
The variable compressor is a swash plate type that c hanges piston stroke in response to the required cooling
capacity.
The tilt of the wobble (swash) plate allows the piston’ s stroke to change so that refrigerant discharge continu-
ously change from 14.5 to 184 cm
3 (0.885 to 11.228 cu in).
RJIA1260E
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ATC-22
< SERVICE INFORMATION >
LUBRICANT
LUBRICANT
Maintenance of Lubricant Quantity in CompressorINFOID:0000000001328166
The lubricant in the compressor circulates through the system with the refrigerant. Add lubricant to compres-
sor when replacing any component or after a large refriger ant leakage occurred. It is important to maintain the
specified amount.
If lubricant quantity is not maintained properly, the following malfunctions may result:
Lack of lubricant: May lead to a seized compressor.
Excessive lubricant: Inadequate cooling (thermal exchange interference)
LUBRICANT
LUBRICANT RETURN OPERATION
Adjust the lubricant quantity according to the test group shown below.
1.CHECK LUBRICANT RETURN OPERATION
Can lubricant return operation be performed?
A/C system works properly.
There is no evidence of a lar ge amount of lubricant leakage.
CAUTION:
If excessive lubricant leakage is noted, never perform the lubricant return operation.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.PERFORM LUBRICANT RETURN OPERATION, PROCEEDING AS FOLLOWS
1. Start the engine, and set to the following conditions:
- Engine speed: Idling to 1,200 rpm
- A/C switch: ON
- Blower speed: Max. position
- Temp. control: Optional [Set so that intake air temperature is 25 to 30 °C (77 to 86 °F).]
- Intake position: Recirculation (REC)
2. Perform lubricant return operation for about 10 minutes.
3. Stop the engine.
>> GO TO 3.
3.CHECK REPLACEMENT PART
Should the compressor be replaced?
YES >> Go to "LUBRICANT ADJUSTING PROCEDURE FOR COMPRESSOR REPLACEMENT".
NO >> Go to "LUBRICANT ADJUSTING PROCEDURE FOR COMPONENTS REPLACEMENT EXCEPT COMPRESSOR".
LUBRICANT ADJUSTING PROCEDURE FOR COMPONENTS REPLACEMENT EXCEPT COM-
PRESSOR
After replacing any of the followi ng major components, add the correct am ount of lubricant to the system.
Amount of lubricant to be added: Name : NISSAN A/C System Oil Type S
Part replaced
Lubricant to be added to system
Remarks
Amount of lubricant
m (US fl oz., Imp fl oz.)
Evaporator 75 (2.5, 2.6) —
Condenser 35 (1.2, 1.2) —
Liquid tank 10 (0.3, 0.4) —
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ATC-24
< SERVICE INFORMATION >
AIR CONDITIONER CONTROL
AIR CONDITIONER CONTROL
Description of Air Conditioner LAN Control SystemINFOID:0000000001328167
The LAN (Local Area Network) syst em consists of unified meter and A/C amp., mode door motor, air mix door
motors and intake door motor.
A configuration of these component s is shown in the figure below.
System ConstructionINFOID:0000000001328168
A small network is constructed between the unifi ed meter and A/C amp., air mix door motors, mode door
motor and intake door motor. The unified meter and A/C amp. and motors are connected by data transmission
lines and motor power supply lines. The LAN network is built through the ground circuits of each door motor.
Addresses, motor opening angle signals, motor stop si gnals and error checking messages are all transmitted
through the data transmission lines connecting the unified meter and A/C amp. and each door motor.
The following functions are contained in LCUs built into the air mix door motors, the mode door motor and the
intake door motor.
Address
Motor opening angle signals
Data transmission
Motor stop and drive decision
Opening angle sensor (PBR function)
Comparison
Decision (Unified meter and A/C amp. indicated value and motor opening angle comparison)
OPERATION
The unified meter and A/C amp. receives data from each of the sensors. The unified meter and A/C amp.
sends mode door, air mix door and intake door opening angle data to the mode door motor LCU, air mix door
motor LCU and intake door motor LCU.
The mode door motor, air mix door motors and intake door motor read their respective signals according to the
address signal. Opening angle indication signals received from the unified meter and A/C amp. and each of
the motor position sensors is compared by the LCUs in each door motor with the existing decision and open-
ing angles. Subsequently, HOT/COLD, DEF/VENT and FRE/ REC operation is selected. The new selection
data is returned to the unified meter and A/C amp.
SJIA1609E
RJIA1747E
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AIR CONDITIONER CONTROLATC-25
< SERVICE INFORMATION >
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TRANSMISSION DATA AND TRANSMISSION ORDER
Unified meter and A/C amp. data is transmitted consecut ively to each of the door motors following the form
shown in figure below.
Sta rt:
Initial compulsory signal is sent to each of the door motors.
Address:
Data sent from the unified meter and A/C amp. are selected according to data-based decisions made by the
air mix door motor, mode door motor and intake 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 decis ion. If the opening angle data have no error, door con-
trol begins.
If an error exists, the received data are 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:
In this procedure, transmitted and received data is check ed for errors. Error data are then compiled. The error
check prevents corrupted data from being used by the ai r mix door motor, the mode door motor and the intake
door motor. Error data can be related to the following symptoms.
Malfunction of electrical frequency
Poor electrical connections
Signal leakage from transmission lines
Signal level fluctuation
Stop Signal:
At the end of each transmission, a stop operation, in-oper ation, or internal malfunction message is delivered to
the unified meter and A/C amp. This comple tes one data transmission and control cycle.
AIR MIX DOOR CONTROL (AUTOMATIC TEMPERATURE CONTROL)
RJIA1748E
RJIA1749E
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ATC-26
< SERVICE INFORMATION >
AIR CONDITIONER CONTROL
The air mix doors are automatically controlled so that in-vehicle temperature is maintained at a predetermined
value by the temperature setting, ambient temper ature, in-vehicle temperature and amount of sunload.
FAN SPEED CONTROL
Blower speed is automatically controlled by the temperature setting, ambient temperature, in-vehicle tempera-
ture, intake temperature, amount of sunload and air mix door position.
With pressing AUTO switch, the blower motor starts to gradually increase air flow volume.
When engine coolant temperature is low, the blower moto r operation is delayed to prevent cool air from flow-
ing.
INTAKE DOOR CONTROL
The intake doors are automatically controlled by the tem perature setting, ambient temperature, in-vehicle tem-
perature, intake temperature, amount of s unload and ON/OFF operation of the compressor.
MODE DOOR CONTROL
The mode door is automatically controlled by the temperat ure setting, ambient temperature, in-vehicle temper-
ature, intake temperature and amount of sunload.
MAGNET CLUTCH CONTROL
When A/C switch, AUTO switch or DEF switch is pr essed, unified meter and A/C amp. transmits compressor
ON signal to BCM.
BCM sends compressor ON signal to ECM, via CAN communication.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sen-
sor signal, throttle angle, etc.). If it judges compre ssor can be turned ON, it sends compressor ON signal to
IPDM E/R, via CAN communication.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.
When sending compressor ON signal to IPDM E/R via CAN communication, ECM simultaneously sends com-
pressor feedback signal to unified meter and A/C amp. via CAN communication.
Unified meter and A/C amp., then, uses input compressor feedback signal to control air inlet.
SELF-DIAGNOSIS SYSTEM
The self-diagnosis system is built into the unified mete r and A/C amp. to quickly locate the cause of malfunc-
tions.
RJIA1957E
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AIR CONDITIONER CONTROLATC-27
< SERVICE INFORMATION >
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Description of Control SystemINFOID:0000000001328169
The control system consists of input sensors, swit ches, the unified meter and A/C amp. (microcomputer) and
outputs. The relationship of these co mponents is shown in the figure below:
Control OperationINFOID:0000000001328170
DISPLAY SCREEN
The operation status of the system is displayed on the screen.
AUTO SWITCH
The compressor, intake doors, air mix doors, mode doors and blower speed are automatically controlled so
that the in-vehicle temperature will reach, and be mainta ined at the set temperature selected by the operator.
SJIA1658E
SJIA1567E
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