INFINITI QX4 2005 Factory Service Manual

ATC-26
AIR CONDITIONER CONTROL
Revision: October 20052005 QX56
Description of Control SystemEJS003X7
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 OperationEJS003X8
Front air control
WJIA1343E
WJIA1397E

AIR CONDITIONER CONTROL
ATC-27
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AT C
Revision: October 20052005 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.

When pressing AUTO switch, air inlet, air outlet, blower speed, and discharge air temperature are auto-
matically controlled.
TEMPERATURE CONTROL DIAL (TEMPERATURE CONTROL) (DRIVER SIDE)
Increases or decreases the set temperature.
TEMPERATURE CONTROL DIAL (TEMPERATURE CONTROL) (PASSENGER SIDE)
Increases or decreases the set temperature.
TEMPERATURE CONTROL DIAL (TEMPERATURE AND MODE CONTROL) (REAR)
Increases or decreases the set temperature. The mode also changes from foot at full hot setting, to foot/vent
mid-range (warm) setting, and then to panel on full cold setting.
RECIRCULATION () SWITCH

When REC switch is ON, REC switch indicator turns ON, and air inlet is set to REC.

When REC switch is turned OFF, or when compressor is turned from ON to OFF, REC switch is automati-
cally turned OFF. REC mode can be re-entered by pressing REC switch again.

REC switch is not operated when DEF switch is turned ON, or at the D/F position.
DEFROSTER () SWITCH
Positions the air outlet doors to the defrost position. Also positions the intake doors to the outside air position.
REAR WINDOW DEFOGGER SWITCH
When switch is ON, rear window is defogged.
OFF SWITCH
The compressor and blower are OFF, the intake doors are 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 (FRONT)
Controls the air discharge outlets.
FRONT BLOWER CONTROL DIAL
Manually control the blower speed. Seven speeds are available for manual control (as shown on the display
screen).

ATC-28
AIR CONDITIONER CONTROL
Revision: October 20052005 QX56
Rear Air Control
TEMPERATURE CONTROL DIAL (TEMPERATURE AND MODE CONTROL)
The temperature increases or decreases the set temperature. The mode also changes from foot at full hot set-
ting, to foot/vent at mid-range (warm) setting, and then to vent at full cold setting.
REAR BLOWER CONTROL DIAL
When the rear blower switch (front) is in the OFF position, the rear blower motor cannot operate.
When the rear blower switch (front) is in the REAR position, it allows the rear blower switch (rear) to control
the rear blower motor speed. In any other position (1-4), the rear blower switch (front) controls the rear blower
motor speed regardless of the rear blower switch (rear) position.
WJIA1042E

AIR CONDITIONER CONTROL
ATC-29
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AT C
Revision: October 20052005 QX56
Discharge Air FlowEJS003X9
FRONT
REAR
WJIA0540E
WJIA0528E
WJIA0541E
WJIA1236E

ATC-30
AIR CONDITIONER CONTROL
Revision: October 20052005 QX56
System Description (Front)EJS003XA
SWITCHES AND THEIR CONTROL FUNCTION
WJIA1680E
WJIA1237E

AIR CONDITIONER CONTROL
ATC-31
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Revision: October 20052005 QX56
System Description (Rear)EJS003XB
SWITCHES AND THEIR CONTROL FUNCTION
WJIA0623E
WJIA1067E

ATC-32
AIR CONDITIONER CONTROL
Revision: October 20052005 QX56
CAN Communication System DescriptionEJS003XC
Refer to LAN-5, "CAN COMMUNICATION" .

TROUBLE DIAGNOSIS
ATC-33
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AT C
Revision: October 20052005 QX56
TROUBLE DIAGNOSISPFP:00004
CONSULT-II Function (HVAC)EJS003XD
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, and turn the
ignition switch ON.
2. Touch “START (NISSAN BASED VHCL)”.
3. Touch “HVAC” on “SELECT SYSTEM” screen. If “HVAC” is not
indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC)
Circuit" .
Diagnostic mode Description
SELF-DIAG RESULTS Displays front air control self-diagnosis results.
DATA MONITOR Displays front air control input/output data in real time.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ECU PART NUMBER Front air control part number can be read.
BBIA0369E
BCIA0029E
BCIA0030E

ATC-34
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
SELF-DIAGNOSIS
Operation Procedure
1. Touch “SELF-DIAG RESULTS” on “SELECT DIAG MODE”
screen to view all set DTC's.
Display Item List
DATA MONITOR
Operation Procedure
1. Touch “DATA MONITOR” on “SELECT DIAG MODE” screen.
2. Touch either “MAIN SIGNALS” or “SELECTION FROM MENU” on “DATA MONITOR” screen.
3. When “SELECTION FROM MENU” is selected, touch items to be monitored. When “MAIN SIGNALS” is
selected, all the items will be monitored.
4. Touch “START”.
5. Touch “RECORD” while monitoring, then the status of the monitored item can be recorded. To stop
recording, touch “STOP”.
BCIA0031E
DTC Description
Reference page
B2573 Battery voltage out of rangeSC-4, "
BATTERY"
B2578 In-vehicle sensor circuit out of range (low)
ATC-140, "In-vehicle Sensor Circuit"B2579 In-vehicle sensor circuit out of range (high)
B257B Ambient sensor circuit short
ATC-137, "
Ambient Sensor Circuit"B257C Ambient sensor circuit open
B257F Optical sensor (Driver) circuit open or short
ATC-143, "
Optical Sensor Circuit"B2580 Optical sensor (Passenger) circuit open or short
B2581 Intake sensor circuit short
ATC-145, "
Intake Sensor Circuit"B2582 Intake sensor circuit open
U1000 CAN bus faultLAN-5, "
CAN COMMUNICATION"
B2587 Stuck buttonATC-147, "FRONT AIR CONTROL"
BCIA0031E
MAIN SIGNALS Monitors all the items.
SELECTION FROM
MENUSelects and monitors the individual item selected.

TROUBLE DIAGNOSIS
ATC-35
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Revision: October 20052005 QX56
Display Item List
*: DENT is displayed when MODE switch is between selections.
Monitor item Value Contents
BATT VIA CAN "V" Displays battery voltage signal.
IGN VIA CAN "ON/OFF" Displays ignition switch signal.
DVR SUNLD SEN "w/m2" Displays optical sensor (driver) signal.
PAS SUNLD SEN "w/m2" Displays optical sensor (passenger) signal.
AMB TEMP SEN "°C/°F" Displays ambient sensor signal.
EVAP TEMP SEN "°C/°F" Displays intake sensor signal.
INCAR TMP SEN "°C/°F" Displays in-vehicle sensor signal.
RR TEMPSET FR "V" Displays air mix door (front) set point signal.
RR TEMPSET RR "V" Displays air mix door (rear) set point signal.
MODE FDBCK "V" Displays mode door motor feedback signal.
DVR MIX FDBCK "V" Displays air mix door motor (driver) feedback signal.
PAS MIX FDBCK "V" Displays air mix door motor (passenger) feedback signal.
RR FDBCK "V" Displays air mix door motor (rear) feedback signal.
DEF FDBCK "V" Displays defroster door motor feedback signal.
RECIRC "ON/OFF" Displays recirculation switch signal.
DEFROST "ON/OFF" Displays defroster switch signal.
AUTO "ON/OFF" Displays AUTO switch signal.
A/C "ON/OFF" Displays A/C switch signal.
MODE "ON/OFF" Displays MODE switch signal.
L TEMP UP "ON/OFF" Displays driver side temperature control dial (temp increase) signal.
L TEMP DOWN "ON/OFF" Displays driver side temperature control dial (temp decrease) signal.
R TEMP UP "ON/OFF" Displays rear temperature control dial [front (temp increase)] signal.
R TEMP DOWN "ON/OFF" Displays Rear temperature control dial [front (temp decrease)] signal.
RR DEFOG "ON/OFF" Displays rear defroster request signal.
FANUP "ON/OFF" Displays front blower motor (blower speed increase) signal.
FANDOWN "ON/OFF" Displays front blower motor (blower speed decrease) signal.
MODE SELECT" [ PNL ]"
" [ MIX ]"
" [ FLR ]"
" [ DEFR ]"
" [ MAX ]"
" [ DENT ]" Displays mode door motor position.