air condition INFINITI QX56 2011 Factory Service Manual

HAC-20
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
1. Intake door 2. In-cabin microfilter 3. Blower motor
4. Evaporator 5. Air mix door (Driver side/Passenger
side)6. Heater core
7. Foot door 8. Ventilator door 9. Upper ventilator door
10. Defroster door Fresh air intake Recirculation air
Center ventilator Side ventilator Upper ventilator
Foot Rear foot Defroster
JMIIA0727ZZ
Switch/Dial position Door position
Ventilator door Foot
doorDefroster
door Intake
door Upper
ventilator door Air mix
door
(Driver side) Air mix
door
(Passen- ger
side)
AUTO switch AUTO — AUTO
MODE switch VENT H E N —
B/L I F N —
FOOT J G O — D/F J G O B —
DEF switch J EPBK —
FRE switch
*—B—
REC switch
*—A—
Upper ventila- tor switch ON — L – M —
OFF — K —
Revision: 2010 May2011 QX56

SYSTEMHAC-21
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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*: Inlet status is displayed by indi cator when activating automatic control
AIR DISTRIBUTION
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Temperature Control
INFOID:0000000006275867
 When ignition switch is in the ON position, A/C auto amp. always
automatically controls temperatur e regardless of front air condi-
tioning operational state.
 A/C auto amp. calculates the target front air mix door opening angle depending on set temperature, in-vehicle temperature (front
side), ambient temperature, and sunload.
 Front air mix door is controlled depending on the comparison of current front air mix door opening angle and target front air mix
door opening angle.
 Regardless of in-vehicle temperature (front side), ambient temper- ature, and sunload, front air mix door is fixed at the fully cold posi-
tion when set temperature is 18.0 °C (60 °F), and at the fully hot
position when set temperature is 32.0 °C (90 °F).
FRONT AUTOMATIC AIR CONDITI ONING SYSTEM : Fail-safeINFOID:0000000006275868
FAIL-SAFE FUNCTION
Temperature
control dial
(Driver side) DUAL
switch:
OFF18.0
°C (60 °F) — C
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO
32.0 °C (90 °F) — D
Temperature control dial
(Driver side) DUAL
switch:
ON18.0
°C (60 °F) — C —
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO—
32.0 °C (90 °F) — D —
Temperature control dial
(Passenger
side) 18.0
°C (60 °F) — C
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO
32.0 °C (90 °F) — D
OFF switch AUTO —
Switch/Dial position
Door position
Ventilator door Foot
doorDefroster
door Intake
door Upper
ventilator door Air mix
door
(Driver side) Air mix
door
(Passen- ger
side)
Discharge air flow
Mode position Condition Air outlet/distribution
VENT FOOT DEF
Center Side Front Rear
DUAL and Up-
per ventilator
switch: OFF 50% 50% — — —
30% 30% 26% 14% —
— 14% 36% 23% 27%
— 12% 32% 20% 36%
—11%——89%
JMIIA0731GB
Revision: 2010 May2011 QX56

HAC-22
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
If a communication error exists between the A/C auto
amp., and the AV control unit and preset switch for 30
seconds or longer, air conditioning is controlled under the following conditions:
When ambient temperature is less than 3 °C (37 °F) and engine coolant tem perature is less than 56°C (133 °F)
When ambient temperature is 3 °C (37 °F) or more, or engine coolant temperature is 56 °C (133 °F) or more
REAR AUTOMATIC AIR CONDITIONING SYSTEM
Compressor : ON
Air outlet : DEF
Air inlet : FRE (Fresh air intake)
Blower fan speed : AUTO
Set temperature : Setting before communication error occurs
Compressor : ON
Air outlet : AUTO
Air inlet : 20% FRE (20% fresh air intake)
Blower fan speed : AUTO
Set temperature : Setting before communication error occurs
Revision: 2010 May2011 QX56

SYSTEMHAC-23
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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REAR AUTOMATIC AIR CONDITION ING SYSTEM : System DiagramINFOID:0000000006275869
REAR AUTOMATIC AIR CONDITIONING SYSTEM : System DescriptionINFOID:0000000006275870
 Rear automatic air conditioning system is c ontrolled by each function of A/C auto amp..
Control by A/C auto amp.-HAC-24, "REAR AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Flow Control"
-HAC-25, "REAR AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control"
-HAC-26, "REAR AUTOMATIC AIR CONDITIONING SYSTEM : Door Control"
-HAC-27, "REAR AUTOMATIC AIR CONDITIONING SYSTEM : Temperature Control"
- Correction for input value of each sensor
Ambient sensor (setting temperature correction)
JMIIA0818GB
Revision: 2010 May2011 QX56

HAC-24
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
 A/C auto amp. controls passenger r
oom temperature so that the optimum level always matches the temper-
ature level that passenger may feel. Correction is applied to the target temperature that is set using temper-
ature control dial, according to ambient temperature detected by ambient sensor.
Rear in-vehicle sensor [in-vehicle temperature (rear side) correction]
 Passenger room temperature (rear side) detected by r ear in-vehicle sensor is corrected for each rear auto-
matic air conditioning control.
Intake sensor (intake temperature correction)
 A/C auto amp. performs correction to change recogniti on intake temperature of A/C auto amp. quickly when
difference is large between recognition intake temperat ure and intake temperature detected by intake tem-
perature sensor. The correction is performed to change recognition intake temperature slowly when differ-
ence is small.
Sunload sensor (sunload amount correction) Sunload amount detected by sunload sensor is correct ed for each rear automatic air conditioning control.
 A/C auto amp. performs correction to change recogni tion sunload amount of A/C auto amp. slowly when
sunload amount changes quickly, for exampl e when entering or exiting a tunnel.
 Front control
Operation by front controller
- Front A/C control (preset switch) transmits the co mmands for rear automatic air conditioning system opera-
tion to AV control unit via communication line, then AV control unit transmits the commands to A/C auto amp.
via CAN communication. A/C auto amp. transmits each indication information to AV control unit via CAN
communication. AV control unit displays each indication information that is received.
Operation by rear controller- Rear A/C control transmits the commands for rear automatic air conditioning system operation to A/C auto
amp. via communication line.
REAR AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Flow ControlINFOID:0000000006275871
DESCRIPTION
 A/C auto amp. changes duty ratio of blower motor dr ive signal and controls air flow continuously. When air
flow is increased, duty ratio of rear blower moto r control signal gradually increases to prevent a sudden
increase in air flow.
 In addition to manual control and automatic control, air flow control is compose of starting fan speed control,
low coolant temperature starting control, high in-vehi cle temperature starting control and fan speed control at
door motor operation
AUTOMATIC AIR FLOW CONTROL
 A/C auto amp. decides target air flow depending on target rear air mix door opening angle.
 A/C auto amp. changes duty ratio of rear blower moto r control signal and controls the air flow continuously
so that air flow matches to target air flow.
 When air outlet is VENT or B/L, the minimum air flow is changed depending on sunload.
STARTING AIR FLOW CONTROL
JMIIA0738GB
Revision: 2010 May2011 QX56

SYSTEMHAC-25
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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 When rear blower motor is activated, A/C auto amp. gradually increases duty ratio of rear blower motor control signal to prevent a
sudden increase in discharge air flow.
 It takes approximately 8 seconds for air flow to reach HI from LOW.
LOW COOLANT TEMPERATURE STARTING CONTROL
If the engine coolant temperature is 56 °C (133 °F) or less, to prevent
a cold discharged air flow, A/C auto amp. suspends rear blower
motor activation for the maximum 150 seconds depending on target
rear air mix door opening angle. After this, rear blower motor control
signal is increased gradually, and rear blower motor is activated.
HIGH IN-VEHICLE TEMPERATURE STARTING CONTROL
When front evaporator fin temperature is high [intake sensor value is 35°C (95 °F) or more], to prevent a hot
discharged air flow, A/C auto amp. suspends rear blower motor activation for approximately 3 seconds so that
rear evaporator is cooled by refrigerant.
FAN SPEED CONTROL AT DOOR MOTOR OPERATION
When rear mode door motor is activated while air flow is more than the specified value, A/C auto amp.
reduces temporarily fan speed wo t hat rear mode door moves smoothly.
REAR AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet ControlINFOID:0000000006275872
 While air outlet is in automatic control, A/C auto amp. selects the
rear mode door position depending on a target rear air mix door
angle and outlet air temperature calculated from sunload.
JMIIA0739GB
JMIIA0740GB
JMIIA0733GB
Revision: 2010 May2011 QX56

HAC-26
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
REAR AUTOMATIC AIR CONDITION ING SYSTEM : Door Control
INFOID:0000000006275873
DOOR MOTOR CONTROL
 LCU (Local Control Unit) is built in to each door moto r. And detects door position by PBR (Potentio Balance
Resistor).
 A/C auto amp. communicates with each LCU via comm unication line. And receives each door position feed
back signal from each LCU.
 Each LCU controls each door to the appropriate pos ition depending on the control signal from A/C auto amp.
when the door movement is complete, transmits the signal of door movement completion to A/C auto amp.
SWITCHES AND THEIR CONTROL FUNCTION
JMIIA0729GB
1. Rear blower motor 2. Rear evaporator 3. Rear air mix door
4. Rear heater core 5. Rear mode door
Recirculation air
Rear ventilator Rear A/C foot
Switch/Dial position Door position
Rear mode door Rear air mix door
AUTO switch Front A/C control
AUTO
Rear A/C control
JMIIA0744ZZ
Revision: 2010 May2011 QX56

SYSTEMHAC-27
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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AIR DISTRIBUTION
REAR AUTOMATIC AIR CONDITIONING SYSTEM : Temperature ControlINFOID:0000000006275874
 When ignition switch is in the ON position, A/C auto amp. always
automatically controls temperatur e regardless of rear air condition-
ing operational state.
 A/C auto amp. calculates the target rear air mix door opening
angle depending on set temperature, in-vehicle temperature (rear
side), ambient temperature, and sunload.
 Rear air mix door is controlled depending on the comparison of
current rear air mix door opening angle and target front air mix
door opening angle.
 Regardless of in-vehicle temperature (rear side), ambient tempera-
ture, and sunload, rear air mix door is fixed at the fully cold position
when set temperature is 18.0 °C (60 °F), and at the fully hot position
when set temperature is 32.0 °C (90 °F).
ACCS (ADVANCED CLIMATE CONTROL SYSTEM)
MODE switch VENT C —
B/L D —
FOOT E —
Temperature control dial (front A/C control)
Temperature control switch (rear A/C control) 18.0
°C (60 °F) — A
18.5 °C (61 °F) ⇔
31.5 °C (89 °F) —AUTO
32.0 °C (90 °F) — B
OFF switch AUTO —
Switch/Dial position
Door position
Rear mode door Rear air mix door
Discharge air flow
Mode position Air outlet/distribution
VENT FOOT
100% —
62% 38%
—100%
JMIIA0734GB
Revision: 2010 May2011 QX56

HAC-28
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
ACCS (ADVANCED CLIMATE CONT ROL SYSTEM) : System Diagram
INFOID:0000000006275875
ACCS (ADVANCED CLIMATE CONTROL SYSTEM) : System DescriptionINFOID:0000000006275876
 ACCS (advanced climate control system) controls pass enger room air. It maintains the cleanliness of the
passenger room air using an in-cabin microfilter and a combination of each of the following functions.
- HAC-28, "
ACCS (ADVANCED CLIMATE CONT ROL SYSTEM) : Automatic Intake Control (Exhaust Gas /
Outside Odor Detecting Mechanism)"
-HAC-29, "ACCS (ADVANCED CLIMATE CONTROL SYSTEM) : Plasmacluster Control"
NOTE:
 Plasmacluster
™ ion technology developed by Sharp Corporation is installed in this item.
 Plasmacluster
™ is a trademark of Sharp Corporation.
 Various operations of ACCS (advanced climate contro l system) are transmitted from preset switch to AV
control unit via communication line and from AV contro l unit to A/C auto amp. via CAN communication. A/C
auto amp. sends each indication information to AV c ontrol unit via CAN communication. AV control unit dis-
plays each indication information that is received.
ACCS (ADVANCED CLIMATE CONTROL SYSTE M) : Automatic Intake Control (Ex-
haust Gas / Outside Odor Detecting Mechanism)
INFOID:0000000006275877
DESCRIPTION
In addition to air inlet automatic control of front automatic air conditioning system, A/C auto amp. controls
automatically air inlet according to signal from ex haust gas / outside odor detecting sensor, so that unpleasant
outside odor does not enter in passenger room.
OPERATION DESCRIPTION
 When pressing auto intake switch while front blower motor is operated and DEF switch is OFF, auto intake switch indicator lamp and intake switch indicator lamp turn ON. Air inlet is fixed to recirculation for approxi-
mately 5 minutes, and then is switched to automatic intake control (exhaust gas / outside odor detecting
mechanism).
 Air inlet switches to recirculation when exhaust gas or outside odor is detected while automatic intake control
(exhaust gas / outside odor detecting mechanism) is operated. After that, air inlet switches to fresh air intake
when exhaust gas or outside odor becomes not detectable.
NOTE:
JMIIA0819GB
Revision: 2010 May2011 QX56

SYSTEMHAC-29
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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 Sensitivity of exhaust gas / out side odor detecting sensor can be changed by “GAS SENSOR ADJUST-
MENT” in “WORK SUPPORT” mode of CONSULT-III. Refer to HAC-70, "
ACCS (ADVANCED CLIMATE
CONTROL SYSTEM) : Exhaust Gas / Outside Odor Detecting Sensor Sensitivity Adjustment Function".
 Automatic intake control (exhaust gas / outside odor detecting mechanism) does not operate when ambient
temperature is −2 °C (28 °F) or less. In this case, control is only for control of automatic air inlet of automatic
air conditioning system.
ACCS (ADVANCED CLIMATE CONTROL SYSTEM) : Plasmacluster Control
INFOID:0000000006275878
DESCRIPTION
Plasmacluster™ control eliminates microbes and reduces odor on interior surface by including high density
Plasmacluster
™ ion in air conditioning outlet air flow.
OPERATION DESCRIPTION
 Plasmacluster™ control operates by interlocking to blower motor. Plasmacluster™ control operates when
blower motor operates.
 Control status is displayed on front air conditioning system display screen. Refer to HAC-37, "
ACCS
(ADVANCED CLIMATE CONTROL SYSTEM) : Switch Name and Function".
NOTE:
 Plasmacluster
™ ion technology developed by Sharp Corporation is installed in this item.
 Plasmacluster
™ is a trademark of Sharp Corporation.
Revision: 2010 May2011 QX56