2011 INFINITI QX56 relay

SYSTEMHAC-15
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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- HAC-17, "FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Air Outlet Control"
-HAC-17, "FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Compressor Control"
-HAC-18, "FRONT AUTOMATIC AIR CONDITION ING SYSTEM : Door Control"
-HAC-21, "FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Temperature Control"
- Correction for input value of each sensor
Ambient sensor (setting temperature correction) A/C auto amp. controls passenger room 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.
Front in-vehicle sensor [in-vehicle temperature (front side) correction]
 Passenger room temperature (front side) detected by front in-vehicle sensor is corrected for each front air
conditioning control (driver side and passenger side)
Intake sensor (intake temperature correction)
 A/C auto amp. performs correction to change recognition 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 correc ted for each air conditioning control (driver side and
passenger side).
 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.
Control by ECM
- Cooling fan control
Refer to EC-41, "
COOLING FAN CONTROL : System Description".
- Air conditioning cut control.
Refer to EC-47, "
AIR CONDITIONING CUT CONTRO L : System Description".
Control by IPDM E/R- Relay control
Refer to PCS-5, "
RELAY CONTROL SYSTEM : System Description".
- Cooling fan control
Refer to PCS-8, "
POWER CONTROL SYSTEM : System Description".
 Front A/C control (preset switch) transmits the co mmands for front 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.
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Flow ControlINFOID:0000000006275862
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 front 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 consist 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 front air mix door opening angle.
 A/C auto amp. changes duty ratio of front blower moto r control signal and controls the air flow continuously
so that air flow matches to target air flow.
Revision: 2010 May2011 QX56

SYSTEMHAC-17
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Outlet ControlINFOID:0000000006275864
 While air outlet is in automatic control, A/C auto amp. selects the
front mode door position depending on a target front air mix door
angle and outlet air temperature calculated from sunload.
 If ambient temperature is excessively low, D/F is selected to pre- vent windshield fogging when air outlet is set to FOOT.
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Compressor Control
INFOID:0000000006275865
DESCRIPTION
 When the compressor activation condition is satisfied while blower motor is activated, A/C auto amp. trans-
mits A/C ON signal and blower fan ON signal to ECM via CAN communication.
 ECM judges that the compressor can be activated depending on each sensors state (refrigerant pressure sensor signal, and others). And transmits A/C compress or request signal to IPDM E/R via CAN communica-
tion.
 IPDM E/R turns A/C relay ON and activates the compressor depending on request from ECM.
COMPRESSOR PROTECTION CONTROL AT PRESSURE MALFUNCTION
When high-pressure side value that is detected by refri gerant pressure sensor is as per the following state,
ECM requests IPDM E/R to turn A/C relay OFF and stops the compressor.
 3.12 MPa (31.82 kg/cm
2, 452.4 psi) or more (When the engine speed is less than 1,500 rpm)
 2.74 MPa (27.95 kg/cm
2, 397.3 psi) or more (When the engine speed is 1,500 rpm or more)
 0.14 MPa (1.43 kg/cm
2, 20.3 psi) or less
COMPRESSOR OIL CIRCULATION CONTROL
When the engine starts while the engine coolant temperature is 56 °C (133 °F) or less, ECM activates the com-
pressor for approximately 6 seconds and circulates the compressor lubricant once.
LOW TEMPERATURE PROTECTION CONTROL
 When intake sensor detects that front evaporator fin temperature is
2.5 °C (37 °F) or less, A/C auto amp. requests ECM to turn com-
pressor OFF, and stops the compressor.
 When the front evaporator fin temperature returns to 5.0 °C (41 °F)
or more, the compressor is activated.
OPERATING RATE CONTROL
When set temperature is other than fully cold or air out let is “VENT”, “B/L” or “FOOT” A/C auto amp. controls
the compressor activation depending on ambient temperature.
AIR CONDITIONING CUT CONTROL
When set engine is running is excessively high load conditi on, ECM requests IPDM E/R to turn A/C relay OFF,
and stops the compressor. Refer to EC-47, "
AIR CONDITIONING CUT CONTRO L : System Description" for
details.
JMIIA0730GB
JMIIA0742GB
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (HVAC)HAC-41
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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*: With ACCS (advanced climate control system)
NOTE:
Perform the inspection of each output device after starting the engine because the compressor is operated.
WORK SUPPORT
*: With ACCS (advanced climate control system)
NOTE:
When the battery cable is disconnected from the negative terminal or when the battery voltage becomes 10 V
or less, the setting of WORK SUPPORT may be cancelled.
Rear A/C relay ON ON ON ON OFF OFF ON
Ionizer
*ON ON ON ON ON ON OFF
Front display (Ion mode)
*CLEAN CLEAN QUICK
CLEAN QUICK
CLEAN QUICK
CLEAN QUICK
CLEAN OFF
Te s t i t e m
MODE 1 MODE 2 MODE 3 MODE 4 MODE 5 MODE 6 MODE 7
Work item Description Refer to
TEMP SET CORRECT Setting change of temperature setting trimmer (front) can be per-
formed. HAC-68, "
FRONT AUTO-
MATIC AIR CONDITION-
ING SYSTEM :
Temperature Setting Trim-
mer (Front)"
BLOWER SET Setting change of foot position setting trimmer can be performed.
HAC-68, "
FRONT AUTO-
MATIC AIR CONDITION-
ING SYSTEM : Foot
Position Setting Trimmer"
REC MEMORY SET
Setting change of inlet port memory function (REC) can be per-
formed. HAC-69, "
FRONT AUTO-
MATIC AIR CONDITION-
ING SYSTEM : Inlet Port
Memory Function (REC)"
FRE MEMORY SET
Setting change of inlet port memory function (FRE) can be per-
formed. HAC-69, "
FRONT AUTO-
MATIC AIR CONDITION-
ING SYSTEM : Inlet Port
Memory Function (FRE)"
GAS SENSOR ADJUSTMENT*Setting change of exhaust gas / outside odor detecting sensor sensi-
tivity adjustment function can be performed. HAC-70, "
ACCS (AD-
VANCED CLIMATE CON-
TROL SYSTEM) :
Exhaust Gas / Outside
Odor Detecting Sensor
Sensitivity Adjustment
Function"
CLEAN SW SET*Setting change of auto intake switch interlocking movement change
function can be performed.
HAC-70, "
ACCS (AD-
VANCED CLIMATE CON-
TROL SYSTEM) : Auto
Intake Switch Interlocking
Movement Change Func-
tion"
REAR TEMP SET CORRECT
Setting change of temperature setting trimmer (rear) can be per-
formed. HAC-68, "
FRONT AUTO-
MATIC AIR CONDITION-
ING SYSTEM :
Temperature Setting Trim-
mer (Front)"
Revision: 2010 May2011 QX56

A/C AUTO AMP.HAC-45
< ECU DIAGNOSIS INFORMATION > [AUTOMATIC AIR CONDITIONING]
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*1: With ACCS (advanced climate control system)
*2: A/C auto amp. is not used for control.
Fail-safeINFOID:0000000006275887
FAIL-SAFE FUNCTION
If a communication error exists between the A/C auto am p., 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 temperature 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
DTC IndexINFOID:0000000006275888
34
(L/O) GroundRear blower motor control
signal Output Ignition switch ON
 Rear fan speed: 1st
speed (manual)
37
(B) —Ground — — —
38
(G/W) Ground Rear A/C relay control signal Output Ignition
switch
ONRear blower
motor: ON
0 V
Rear blower
motor: OFF 12 V
Te r m i n a l N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ − Signal name Input/
Output
JSIIA0096ZZ
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
DTC Items
(CONSULT-III screen terms) Reference
U1000 CAN COMM CIRCUIT HAC-72, "
DTC Logic"
U1010 CONTROL UNIT (CAN)HAC-73, "DTC Logic"
B2578 IN-VEHICLE SENSORHAC-74, "DTC Logic"
B2579 IN-VEHICLE SENSORHAC-74, "DTC Logic"
B257B AMBIENT SENOR HAC-77, "DTC Logic"
B257C AMBIENT SENOR HAC-77, "DTC Logic"
B2581 INTAKE SENSORHAC-80, "DTC Logic"
B2582 INTAKE SENSORHAC-80, "DTC Logic"
Revision: 2010 May2011 QX56

HAC-122
< DTC/CIRCUIT DIAGNOSIS >[AUTOMATIC AIR CONDITIONING]
FRONT BLOWER MOTOR
NOTE:
Calculate drive signal duty ratio as shown in the figure.
T2 = Approx. 1.6 ms
Is the inspection result normal?
YES >> Replace front blower motor. Refer to VTL-16, "FRONT A/C UNIT : Removal and Installation".
NO >> Replace A/C auto amp.. Refer to HAC-146, "
Removal and Installation".
6.CHECK BLOWER RELAY GROUND CIRCUIT
Check continuity between fuse bl ock (J/B) harness connector and ground.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair harness or connector.
7.CHECK BLOWER RELAY
Check blower relay. Refer to HAC-123, "
Component Inspection (Blower Relay)".
Is the inspection result normal?
YES >> Repair harness or connector between front blower motor and fuse block (J/B).
NO >> Replace blower relay.
Component Inspection (Front Blower Motor)INFOID:0000000006275969
1.CHECK FRONT BLOWER MOTOR-I
1. Remove front blower motor.
2. Check that there is not any mixing foreign object in the front blower motor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace front blower motor. Refer to VTL-16, "
FRONT A/C UNIT : Removal and Installation".
2.CHECK FRONT BLOWER MOTOR-II
Check that there is not breakage or damage in the front blower motor.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Replace front blower motor. Refer to VTL-16, "
FRONT A/C UNIT : Removal and Installation".
3.CHECK FRONT BLOWER MOTOR-III
Check that front blower motor turns smoothly.
Is the inspection result normal?
YES >> INSPECTION END
Front blower motor Condition Duty ratio
(Approx.)
Connector Terminal Fan speed (manual)
VENT mode
M272 2 1st 25 %
2nd 33 % 3rd 41 %4th 51 %
5th 61 %
6th 69 %
7th 81 %
JPLIA1210GB
Fuse block (J/B) —Continuity
Connector Terminal
M3 7C Ground Existed
Revision: 2010 May2011 QX56

FRONT BLOWER MOTORHAC-123
< DTC/CIRCUIT DIAGNOSIS > [AUTOMATIC AIR CONDITIONING]
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NO >> Replace front blower motor. Refer to VTL-16, "FRONT A/C UNIT : Removal and Installation".
Component Inspection (Blower Relay)INFOID:0000000006275970
1.CHECK BLOWER RELAY
1. Turn ignition switch OFF.
2. Remove blower relay.
3. Check continuity between blower relay terminal 3 and 5 when voltage is supplied between terminal 1 and 2.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace blower relay.
Terminal Voltage Continuity
35 ON Existed
OFF Not existed
JSIIA1551ZZ
Revision: 2010 May2011 QX56

HAC-128
< DTC/CIRCUIT DIAGNOSIS >[AUTOMATIC AIR CONDITIONING]
REAR A/C SOLENOID VALVE
REAR A/C SOLENOID VALVE
Diagnosis ProcedureINFOID:0000000006275976
1.CHECK FUSE
1. Turn ignition switch OFF.
2. Check 10A fuse [No.4, located in fuse block (J/B)]. NOTE:
Refer to PG-140, "
Fuse, Connector and Terminal Arrangement".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace the blown fuse after repairing the affected circuit if a fuse is blown.
2.CHECK REAR A/C SOLENOID VALVE POWER SUPPLY
1. Disconnect rear A/C solenoid valve connector.
2. Turn ignition switch ON and front air conditioning system ON.
3. Check voltage between rear A/C solenoid valve harness connector and ground when rear blower motor is operated.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 4.
3.CHECK REAR A/C SOLENOID VALVE GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between rear A/C solenoid valve harness connector and ground.
Is the inspection result normal?
YES >> Replace rear expansion valve assembly. Refer to HA-49, "EXPANSION VALVE : Removal and
Installation".
NO >> Repair harness or connector.
4.CHECK REAR A/C RELAY POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect rear A/C relay connector.
3. Turn ignition switch ON.
4. Check voltage between rear A/C relay harness connector and ground.
Is the inspection result normal?
YES >> GO TO 5.
+
−Condition Vo l ta g e
(Approx.)
Rear A/C solenoid valve
Connector Terminal
B207 1 Ground Rear blower motor ON Battery voltage
OFF 0 V
Rear A/C sole noid valve
—Continuity
Connector Terminal
B207 2 Ground Existed
+ −Vol tag e
(Approx.)
Rear A/C relay
Connector Terminal
E87 1
Ground Battery voltage
3
Revision: 2010 May2011 QX56

REAR A/C SOLENOID VALVEHAC-129
< DTC/CIRCUIT DIAGNOSIS > [AUTOMATIC AIR CONDITIONING]
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NO >> Repair harness or connector between rear A/C relay and fuse block (J/B).
5.CHECK REAR A/C RERAY CONTROL CIRCUIT FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector.
3. Check continuity between rear A/C relay har ness connector and A/C auto amp. harness connector.
Is the inspection result normal?
YES >> GO TO 6.
NO >> Repair harness or connector.
6.CHECK REAR A/C RELAY CONTROL CIRCUIT FOR SHORT
Check continuity between rear A/C relay harness connector and ground.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair harness or connector.
7.CHECK REAR A/C SOLENOID VALVE POWER SUPPLY CIRCUIT
Check continuity between rear A/C relay harness c onnector and rear A/C solenoid valve harness connector.
Is the inspection result normal?
YES >> GO TO 8.
NO >> Repair harness or connector.
8.CHECK REAR A/C RELAY
Check rear A/C relay. Refer to HAC-129, "
Component Inspection".
Is the inspection result normal?
YES >> Replace A/C auto amp.. Refer to HAC-146, "Removal and Installation".
NO >> Replace rear A/C relay.
Component InspectionINFOID:0000000006275977
1.CHECK REAR A/C RELAY
1. Remove rear A/C relay.
Rear A/C relay A/C auto amp. Continuity
Connector Terminal Connector Terminal
E87 2 M50 38 Existed
Rear A/C relay —Continuity
Connector Terminal
E87 2 Ground Not existed
Rear A/C relay Rear A/C solenoid valve Continuity
Connector Terminal Connector Terminal
E87 5 B207 1 Existed
Revision: 2010 May2011 QX56