2011 INFINITI QX56 heating

HAC-134
< SYMPTOM DIAGNOSIS >[AUTOMATIC AIR CONDITIONING]
FRONT AUTOMATIC AIR CONDITIONING SYSTEM
Compressor does not operate. Circuit between magnet clutch and
IPDM E/R
 Magnet clutch
 IPDM E/R (A/C relay)
 Circuit between ECM and refriger- ant pressure sensor
 Refrigerant pressure sensor
 CAN communication circuit
 A/C auto amp. HAC-142, "Diagnosis Procedure"
 Insufficient cooling.
 No cool air comes out. (Air flow volume is normal.)
 Magnet clutch control system
 Drive belt slipping
 Refrigerant cycle
 Air leakage from each duct
 A/C auto amp. connection recogni-
tion signal circuit
 Temperature settin g trimmer (front)HAC-138, "FRONT AIR CONDI-
TIONER : Diagnosis Procedure"
 Insufficient heating.
 No warm air comes out. (Air flow volume is nor-
mal.)  Engine cooling system
 Heater hose
 Heater core
 Air leakage from each duct
 Temperature settin
g trimmer (front)HAC-140, "FRONT AIR CONDI-
TIONER : Diagnosis Procedure"
Noise is heard when front
air conditioning system op-
erates. During compressor
operation
Refrigerant cycle
HA-27, "
Symptom Table"
During front blower
motor operation Mixing any foreign object in front
blower motor
 Front blower motor fan breakage
 Front blower motor rotation inferiori- ty HAC-122, "Component Inspection
(Front Blower Motor)"
 Memory function does not operate.
 Setting temperature is not memorized.
 Battery power supply system of A/C
auto amp.
 A/C auto amp. HAC-110, "A/C AUTO AMP. : Diag-
nosis Procedure"
Symptom Corresponding malfunction part Reference
Revision: 2010 May2011 QX56

HAC-136
< SYMPTOM DIAGNOSIS >[AUTOMATIC AIR CONDITIONING]
REAR AUTOMATIC AIR CONDITIONING SYSTEM
 Insufficient heating.
 No warm air comes out. (Air flow volume is nor-
mal.)  Engine cooling system
 Heater hose
 Rear heater core
 Air leakage from each duct
 Temperature setting trimmer (rear)
HAC-141, "REAR AIR CONDI-
TIONER : Diagnosis Procedure"
Noise is heard when rear blower motor operates.
 Mixing any foreign object in rear
blower motor
 Rear blower motor fan breakage
 Rear blower motor rotation inferiori- ty HAC-132, "Component Inspection"
Symptom Corresponding malfunction part Reference
Revision: 2010 May2011 QX56

HAC-140
< SYMPTOM DIAGNOSIS >[AUTOMATIC AIR CONDITIONING]
INSUFFICIENT HEATING
INSUFFICIENT HEATING
FRONT AIR CONDITIONER
FRONT AIR CONDITIONER : DescriptionINFOID:0000000006275990
Symptom Insufficient heating
 No warm air comes out. (Air flow volume is normal.)
FRONT AIR CONDITIONER
: Diagnosis ProcedureINFOID:0000000006275991
NOTE:
Perform self-diagnoses with on board diagnosis and CO NSULT-III before performing symptom diagnosis. If
DTC is detected, perform the corresponding diagnosis.
1.CHECK COOLING SYSTEM
1. Check engine coolant level and check leakage. Refer to CO-8, "
Inspection".
2. Check reservoir tank cap. Refer to CO-11, "
RESERVOIR TANK CAP : Inspection".
3. Check water flow sounds of the engine coolant. Refer to CO-9, "
Refilling".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Refill engine coolant and repair or repl ace parts depending on the inspection results.
2.CHECK HEATER HOSE
Check installation of heater hose by visually or touching.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace parts depending on the inspection results.
3.CHECK FRONT HEATER CORE
1. Check temperature of inlet hose and outlet hose of front heater core.
2. Check that inlet side of front heater core is hot and t he outlet side is slightly lower than/almost equal to the
inlet side.
CAUTION:
Always perform the temperature in spection in a short period of time because the engine coolant
temperature is very hot.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace front heater core. Refer to HA-44, "
HEATER CORE : Removal and Installation".
4.CHECK AIR LEAKAGE FROM EACH DUCT
Check duct and nozzle, etc. of front air conditioning system for air leakage.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace parts depending on the inspection results.
5.CHECK SETTING OF TEMPERATURE SETTING TRIMMER (FRONT)
1. Check setting value of temperature setting trimmer (front). Refer to HAC-68, "
FRONT AUTOMATIC AIR
CONDITIONING SYSTEM : Temperature Setting Trimmer (Front)".
2. Check that temperature setting trimmer (front) is set to “ − direction”.
NOTE:
The control temperature can be set by t he temperature setting trimmer (front).
3. Set difference between the set temperature and control temperature to “0”.
Are the symptoms solved?
YES >> INSPECTION END
NO >> Replace A/C auto amp.. Refer to HAC-146, "
Removal and Installation".
REAR AIR CONDITIONER
Revision: 2010 May2011 QX56

INSUFFICIENT HEATINGHAC-141
< SYMPTOM DIAGNOSIS > [AUTOMATIC AIR CONDITIONING]
C
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F
G H
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M A
B
HAC
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REAR AIR CONDITIONER : DescriptionINFOID:0000000006275992
Symptom
 Insufficient heating
 No warm air comes out. (Air flow volume is normal.)
REAR AIR CONDITIONER : Diagnosis ProcedureINFOID:0000000006275993
CAUTION:
Perform the self-diagnoses with on board diagnosi s and CONSULT-III before performing symptom
diagnosis. If any malfunction result or DTC is detected, perform the corresponding diagnosis.
1.CHECK COOLING SYSTEM
1. Check engine coolant level and check leakage. Refer to CO-8, "
Inspection".
2. Check reservoir tank cap. Refer to CO-11, "
RESERVOIR TANK CAP : Inspection".
3. Check water flow sounds of the engine coolant. Refer to CO-9, "
Refilling".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Refill the engine coolant and repair or replace the parts depending on the inspection results.
2.CHECK HEATER HOSE
Check installation of heater hose by visually or touching.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace parts depending on the inspection results.
3.CHECK REAR HEATER CORE
1. Check temperature of inlet hose and outlet hose of rear heater core.
2. Check that the inlet side of rear heater core is hot and the outlet side is slightly lower than/almost equal to
the inlet side.
CAUTION:
Always perform the temperature inspection in a sh ort period of time because the engine coolant
temperature is very hot.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace rear heater core. Refer to HA-48, "
HEATER CORE : Removal and Installation".
4.CHECK AIR LEAKAGE FROM EACH DUCT
Check duct and nozzle, etc. of the rear air conditioning system for air leakage.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace parts depending on the inspection results.
5.CHECK SETTING OF TEMPERATURE SETTING TRIMMER (REAR)
1. Check setting value of temperature setting trimmer (rear). Refer to HAC-69, "
REAR AUTOMATIC AIR
CONDITIONING SYSTEM : Temperature Setting Trimmer (Rear)".
2. Check that the temperature setting trimmer is set to “ − direction”.
NOTE:
The control temperature can be set by the temperature setting trimmer (rear).
3. Set the difference between the set temperature (rear) and control temperature to “0”.
Are the symptoms solved?
YES >> INSPECTION END
NO >> Replace A/C auto amp.. Refer to HAC-146, "
Removal and Installation".
Revision: 2010 May2011 QX56

LU-2
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Liquid GasketINFOID:0000000006289611
LIQUID GASKET APPLICATION PROCEDURE
1. Remove old liquid gasket adhering to the liquid gasket application surface and the mating surface.• Remove liquid gasket completely from the liquid gasket application surface, mounting bolts, and boltholes.
2. Wipe the liquid gasket application surface and the ma ting surface with white gasoline (lighting and heating
use) to remove adhering moisture, grease and foreign materials.
3. Apply liquid gasket to the liquid gasket application surface. Use Genuine RTV Silicone Seal ant or equivalent. Refer to GI-22, "
Recommended Chemical Prod-
ucts and Sealants".
 Within five minutes of liquid gasket application, install the mating component.
 If liquid gasket protrudes, wipe it off immediately.
 Do not retighten mounting bolts or nuts after the installation.
 After 30 minutes or more have passed from the installation, fill engine oil and engine coolant.
Revision: 2010 May2011 QX56

SBC-8
< SYSTEM DESCRIPTION >
SYSTEM
 When the vehicle inclined excessively
 When comfort function operates
OPERATION CONDITION
Operation while driving
 Operation start and stop conditions of pre-crash seat belt system are as shown in the following table.
 The activation and deactivation conditions of pre-crush seat belt are as per the following.
NOTE:
For details of intelligent brake assist system.Refer to BRC-152, "
INTELLIGENT BRAKE ASSIST : System
Description".
Comfort function
 Seat belt is retracted and the looseness is reduced in the state as shown in the following table.
 Operation start and stop conditions of pre-crash seat belt system are as shown in the following table.
Operation Prohibition Condition
Pre-crash seat belt system does not operate in the following conditions.
 When seat belt is not fastened (only the seat belt that is not fastened does not operate)
 When motor is overheat due to contentious operation*1
 When the system is in fail-safe mode *1: System operation is temporarily deactivated to av oid overheating, when comfort function is continuously
operated (18 times or more) during a short period of time by fastening and unfastening seat belts or opening
and closing doors.
MALFUNCTION WARNING
When system malfunction is detected, comfort function is deactivated to warn customer of system malfunc-
tion.
Operation item Operation start condition Operation stop condition
During emergency brake operation  Vehicle speed is 15 km/h (9 MPH) or more
 Emergency braking status is detected
 During acceleration
 When stopped
When ABS continuously operates  ABS continuously operates for 2 seconds or
more
 Brake pedal is in depressed state
When intelligent brake assistance oper-
ates System detects that intelligent brake assistance is
in operating status
2 seconds after operation start
When lateral slippage during cornering
occurs  Vehicle speed is 30 km/h (19 MPH) or more
 System detects that the vehicle is in lateral slip-
page state
 System detects that the vehicle is driving on a curve  Vehicle stopped
 1 second or more after maintaining
steering wheel angle in straight driv-
ing state
When steering wheel is rotated for emer-
gency  Vehicle speed is 60 km/h (36 MPH) or more
 Steering wheel angle is 90 degrees or more
 System detects that steering wheel is rotated for
emergency
When the vehicle inclined excessively  Vehicle speed is 30 km/h (19 MPH) or more
 System detects that the vehicle inclined exces-
sively  During acceleration
 Vehicle stopped
Operation item Activating condition Deactivating condition
Door open  Seat belt is in not fastened state
 Door is operated to open from closed
 Vehicle stopped  Seat belt retract is complete
 13 seconds after start retracting
Seat belt is fastened  When door is closed
 Seat belt is fastened  Seat belt is unfastened
 1 second after operation
Seat belt is release Seat belt is unfastened  Seat belt retract is complete
 10 seconds after start retracting
Revision: 2010 May2011 QX56

SBC-16
< ECU DIAGNOSIS INFORMATION >
PRE-CRASH SEAT BELT CONTROL UNIT (DRIVER SIDE)
DTC Index
INFOID:0000000006237885
DTC Trouble diagnosis name
(CONSULT-III display) DTC detection condition Reference
U0126 STRG ANG SEN SIG Steering angle sensor malfunction is received SBC-33
U0428 STRG ANGL CAL Steering angle sensor calibration incomplete signal is receivedSBC-34
U1000 CAN COMM CIRCUITPre-crash seat belt control unit cannot transmit and receive CAN
communication signal for 2 seconds or more SBC-35
B2451 SEAT BLT MTR DR CIRC Motor or control unit malfunction
 Seat belt motor circuit is open or shorted
SBC-36
B2452 SEAT BLT MTR AS CIRC Motor or control unit malfunction
 Seat belt motor circuit is open or shorted SBC-37
B2453 BR_STROKE_SEN_CIRC
 Brake pedal stroke sensor malfunction
 Brake pedal stroke sensor circuit is open or shorted SBC-38
B2454 SEAT BLT PWR DR CIRC Motor power su
pply circuit is open or shortedSBC-41
B2455 CONTROL UNIT DR Malfunction in pre-crash seat belt control unit SBC-42
B2456 SEAT BLT PWR AS CIRC Motor power supply circuit is open or shortedSBC-43
B2457 CONTROL UNIT AS Malfunction in pre-crash seat belt control unit SBC-44
B2458 LOCAL COMM Local communication line open or shortedSBC-45
B2461 VHCL SPEED SIGNAL Vehicle speed signal malfunction is received SBC-47
B2463 ROLLOVER SIGNAL Rollover signal malfunction is received SBC-48
B2466 DR/AS CONTROL UNIT Control unit is out of the vehicle specificationSBC-49
B2470 SYS HEAT PROTC DRDeactivation for cooling to prevent system heating due to continuous
operation SBC-50
B2471 SYS HEAT PROTC ASDeactivation for cooling to prevent system heating due to continuous
operation
SBC-51
Revision: 2010 May2011 QX56

SBC-50
< DTC/CIRCUIT DIAGNOSIS >
B2470 SYS HEAT PROTC DR
B2470 SYS HEAT PROTC DR
DescriptionINFOID:0000000006237924
When fastening and unfastening seat belt or opening and closing door is repeated continuously for a short
period of time, the system temporarily deactivates the retracting function of seat belt to prevent excessive
heating. The system recovers automatically.
DTC LogicINFOID:0000000006237925
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-50, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006237926
1.CHECK THE VEHICLE CONDITION WITH CONSULT-III DATA MONITOR
1. Check “HEAT PROTC LH” in “D ATA MONITOR” with CONSULT-III.
2. Wait until “OFF” appears.
3. Perform the “self-diagnosis result” with CONSULT-III, after performing the check.
4. Touch “ERASE”.
5. Perform DTC Confirmation Procedure. Refer to SBC-50, "
DTC Logic".
Is DTC B2470 displayed again?
YES >> GO TO 2.
NO >> INSPECTION END
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
B2470 SYS HEAT PROTC DR Deactivate s to prevent excessive heating Comfort function activates continuously in a
short period of time.
Revision: 2010 May2011 QX56