INFINITI QX56 2004 Factory Service Manual

ATC-26
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
Description of Control SystemEJS002BY
The control system consists of input sensors, switches, the front air control (microcomputer) and outputs.
The relationship of these components is shown in the figure below:
Control OperationEJS002BZ
Front air control
WJIA0755E
WJIA0756E

AIR CONDITIONER CONTROL
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Revision: August 20072004 QX56
DISPLAY SCREEN
Displays the operational status of the system.
AUTO SWITCH

The compressor, intake door, air mix doors, outlet doors and blower speed are automatically controlled so
that the in-vehicle temperature will reach, and be maintained at the set temperature selected by the oper-
ator.
TEMPERATURE DIAL (DRIVER)
Increases or decreases the driver zone temperature.
TEMPERATURE DIAL (PASSENGER)
Increases or decreases the passenger zone temperature.
RECIRCULATION SWITCH ()

When pressed an indicator turns ON in the display, and air inlet is set to recirculation mode.

Recirculation mode is cancelled by pressing the switch again, turning ON the front defroster, pressing the
OFF switch, or pressing the A/C switch to turn off the A/C system and compressor.
DEFROSTER () SWITCH
Positions the air outlet doors to the defrost position. Also positions the intake door to the outside air position.
REAR WINDOW DEFOGGER SWITCH
When switch is ON, rear window is defogged.
OFF SWITCH (HOLD FAN DOWN SWITCH UNTIL SYSTEM SHUTS OFF)
The compressor and blower are OFF, the intake door is set to the outside air position, and the air outlet doors
are set to the foot (75% foot and 25% defrost) position.
A/C SWITCH
The compressor is ON or OFF.
(Pressing the A/C switch when the AUTO switch is ON will turn off the A/C switch and compressor.)
MODE SWITCH
Controls the air discharge outlets.
FRONT FAN SWITCH
Manually controls the blower speed. Seven speeds are available for manual control (as shown on the display
screen).
REAR FAN SWITCH (FRONT)
Manually controls the rear blower speed. Four speeds are available for manual control. When the rear fan
switch (front) is in the off (0) position, the rear blower motor cannot operate. Position (R) allows control of rear
blower speed and rear temperature/mode operation to be transferred to rear air control.
REAR TEMPERATURE/MODE DIAL (FRONT)
Increases or decreases the rear zone temperature and adjusts the mode simultaneously. FLOOR is full hot
setting, FLOOR/PANEL is warm setting, and PANEL is full cold setting.

ATC-28
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
Rear Air Control
REAR TEMPERATURE/MODE DIAL (REAR)
Increases or decreases the rear zone temperature and adjusts the mode simultaneously. FLOOR is full hot
setting, FLOOR/PANEL is warm setting, and PANEL is full cold setting. Operates only with rear fan switch
(front) is in the (R) position.
REAR FAN CONTROL SWITCH (REAR)
When the rear fan switch (front) is in the (R) position, it allows the rear fan switch (rear) to control the blower
motor speed. In any other position (1-4), the rear fan switch (front) controls the rear blower motor speed
regardless of the rear fan switch (rear) position.
LJIA0024E

AIR CONDITIONER CONTROL
ATC-29
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Revision: August 20072004 QX56
Discharge Air FlowEJS002C0
FRONT
REAR
WJIA0540E
WJIA0528E
WJIA0541E
WJIA0893E

ATC-30
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
System Description (Front)EJS002C1
CONTROLS AND THEIR FUNCTIONS
WJIA1680E
WJIA0757E

AIR CONDITIONER CONTROL
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System Description (Rear)EJS002C2
CONTROLS AND THEIR FUNCTIONS
WJIA0623E
WJIA0758E

ATC-32
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
CAN Communication System DescriptionEJS002C3
Refer to LAN-5, "CAN COMMUNICATION" .

TROUBLE DIAGNOSIS
ATC-33
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Revision: August 20072004 QX56
TROUBLE DIAGNOSISPFP:00004
CONSULT-II Function (BCM)EJS002C4
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II BASIC OPERATION
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
1. With the ignition switch OFF, connect CONSULT-II and CON-
SULT-II CONVERTER to the data link connector, then turn the
ignition switch ON.
2. Touch “START (NISSAN BASED VHCL)”.
3. Touch “BCM” on “SELECT SYSTEM” screen. If “BCM” is not
indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC)
Circuit" .
BCM diagnostic
test itemDiagnostic mode Description
Inspection by partWORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the BCM
for setting the status suitable for required operation, input/output signals are
received from the BCM and received data is displayed.
DATA MONITOR Displays BCM input/output data in real time.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
SELF-DIAG RESULTS Displays BCM self-diagnosis results.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ECU PART NUMBER BCM part number can be read.
CONFIGURATION Performs BCM configuration read/write functions.
BBIA0369E
BCIA0029E
BCIA0030E

ATC-34
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
DATA MONITOR
Operation Procedure
1. Touch “AIR CONDITIONER” on “SELECT TEST ITEM” screen.
2. Touch “DATA MONITOR” on “SELECT DIAG MODE” screen.
3. Touch either “ALL SIGNALS” or “SELECTION FROM MENU” on
“DATA MONITOR” screen.
4. Touch “START”.
5. When “SELECTION FROM MENU” is selected, touch items to
be monitored. When “ALL SIGNALS” is selected, all the items
will be monitored.
6. Touch “RECORD” while monitoring, then the status of the moni-
tored item can be recorded. To stop recording, touch “STOP”.
Display Item List
WJIA0468E
BCIA0031E
All signals Monitors all the items.
Selection from menu Selects and monitors the individual item selected.
WJIA0469E
Monitor item name “operation or
unit”Contents
IGN ON SW “ON/OFF” Displays “IGN Position (ON)/OFF, ACC Position (OFF)” status as judged from ignition switch signal.
COMP ON SIG “ON/OFF” Displays “COMP (ON)/COMP (OFF)” status as judged from air conditioner switch signal.
FAN ON SIG “ON/OFF” Displays “FAN (ON)/FAN (OFF)” status as judged from blower motor switch signal.

TROUBLE DIAGNOSIS
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Revision: August 20072004 QX56
How to Perform Trouble Diagnosis for Quick and Accurate RepairEJS002C5
WORK FLOW
SYMPTOM TABLE
*1ATC-56, "Operational Check (Front)"
or AT C - 5 9 , "
Operational Check
(Rear)" .
SHA9 00 E
Symptom Reference Page
A/C system does not come on. Go to Trouble Diagnosis Procedure for A/C System.AT C - 6 0 , "
Power
Supply and
Ground Circuit for
Front Air Control"
A/C system display is malfunctioning. Go to "Navigation System".AV-61, "NAVIGA-
TION SYSTEM"
A/C system cannot be controlled. Go to Self-diagnosis Function.AT C - 5 3 , "
A/C Sys-
tem Self-diagno-
sis Function"
Air outlet does not change.
Go to Trouble Diagnosis Procedure for Mode Door Motor.AT C - 6 3 , "Mode
Door Motor Cir-
cuit"Mode door motor is malfunctioning.
Discharge air temperature does not change.
Go to Trouble Diagnosis Procedure for Air Mix Door Motor.ATC-67, "
Air Mix
Door Motor Cir-
cuit"Air mix door motor is malfunctioning.
Intake door does not change.
Go to Trouble Diagnosis Procedure for Intake Door Motor.ATC-76, "
Intake
Door Motor Cir-
cuit"Intake door motor is malfunctioning.
Defroster door motor is malfunctioning. Go to Trouble Diagnosis Procedure for Defroster Door Motor.AT C - 7 9 ,
"Defroster Door
Motor Circuit"
Front blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Front Blower Motor.AT C - 8 3 , "Front
Blower Motor Cir-
cuit"
Rear blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Rear Blower Motor.AT C - 9 0 , "Rear
Blower Motor Cir-
cuit"
Rear discharge air temperature and/or air
outlet does not change.Go to Trouble Diagnosis Procedure for Rear Air Control circuit.ATC-101, "Rear
Air Control Circuit"
Magnet clutch does not engage. Go to Trouble Diagnosis Procedure for Magnet Clutch.ATC-104, "Mag-
net Clutch Circuit"
Insufficient cooling Go to Trouble Diagnosis Procedure for Insufficient Cooling.AT C - 11 0 , "Insuffi-
cient Cooling"
Insufficient heating Go to Trouble Diagnosis Procedure for Insufficient Heating.AT C - 11 7 , "Insuffi-
cient Heating"
Noise Go to Trouble Diagnosis Procedure for Noise.ATC-118, "Noise"