2009 INFINITI QX56 suspension

SCS-36
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM INOPERATIVE
SUSPENSION CONTROL SYSTEM INOPERATIVE
DescriptionINFOID:0000000003772355
The suspension control system does not activate. It does not raise or lower the vehicle in response to ride
height changes.
Diagnosis ProcedureINFOID:0000000003772356
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control unit power and ground pass inspection?
YES >> GO TO 2.
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition switch ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3.
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.CHECK GENERATOR "L" CIRCUIT SIGNAL
CONSULT-III DATA MONITOR
1. Start the engine.
2. Select "ACG L" of AIR LE VELIZER data monitor item.
3. Check the monitor status.
Is the generator "L" signal operating normally?
YES >> GO TO 4.
NO >> Check generator L circuit. Refer to CHG-12, "
Diagnosis Procedure".
4.SUSPENSION AIR COMPRESSOR POWER AND GROUND INSPECTION
Check the suspension air compressor power and ground supply. Refer to SCS-17, "
SUSPENSION AIR COM-
PRESSOR : Diagnosis Procedure".
Does the suspension air compressor power and ground pass inspection?
YES >> System is operating normally.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
ACG L: OFF with charge light OFF
: ON with charge light ON
Revision: December 20092009 QX56

SUSPENSION CONTROL SYSTEM DOES NOT RAISE
SCS-37
< SYMPTOM DIAGNOSIS >
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SUSPENSION CONTROL SYST EM DOES NOT RAISE
DescriptionINFOID:0000000003772357
The suspension control system does not raise the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000003772358
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control uni t power and ground pass inspection?
YES >> GO TO 2.
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3.
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.SUSPENSION AIR COMPRESSOR POWER AND GROUND INSPECTION
Check the suspension air compressor power and ground supply. Refer to SCS-17, "
SUSPENSION AIR COM-
PRESSOR : Diagnosis Procedure".
Does the suspension air compress or power and ground pass inspection?
YES >> Inspect for a weak compressor, leak or restriction in the system. Repair or replace malfunctioning
part.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
Revision: December 20092009 QX56

SCS-38
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
DescriptionINFOID:0000000003772359
The suspension control system does not lower the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000003772360
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control unit power and ground pass inspection?
YES >> GO TO 2.
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3.
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.EXHAUST VALVE SOLENOID CIRCUIT INSPECTION
Check the exhaust valve solenoid circuit. Refer to SCS-23, "
Component Function Check".
Does the exhaust valve solenoid circuit pass inspection?
YES >> Inspect for a restriction in the system . repair or replace the malfunctioning part.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
Revision: December 20092009 QX56

PRECAUTIONSSCS-39
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000005867805
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SR and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
• When working near the Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
• When using air or electric power tools or hammers, always switch the Ignition OFF, disconnect the battery, and wait at least 3 minutes before performing any service.
Precaution for Rear SuspensionINFOID:0000000003772362
• When installing the rubber bushings, the final tightening must be done under unladen condition and with thetires on level ground. Oil will shorten the life of the rubber bushings, so wipe off any spilled oil immediately.
• Unladen condition means the fuel tank, engine coolant and lubricants are at the full specification. The spare tire, jack, hand tools, and mats are in their designated positions.
• After installing suspension components, check the wheel alignment.
• Caulking nuts are not reusable. Always use new caulking nuts for installation. New caulking nuts are pre-
oiled, do not apply any additional lubrication.
Revision: December 20092009 QX56

ST-12
< SYMPTOM DIAGNOSIS >
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
SYMPTOM DIAGNOSIS
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NVH Troubleshooting ChartINFOID:0000000003775124
Use chart below to help you find the cause of the symp tom. If necessary, repair or replace these parts.
×: ApplicableReference page
ST-13, "Checking Fluid Level"
ST-13, "Air Bleeding Hydraulic System"
ST-37ST-37ST-37ST-13ST-36ST-38
EM-13, "Checking Drive Belts"
ST-36ST-36ST-38ST-36ST-20ST-38
DLN-184, "NVH Troubleshooting Chart"DLN-208, "NVH Troubleshooting Chart"FAX-5, "NVH Troubleshooting Chart"FSU-5, "NVH Troubleshooting Chart"WT-36, "NVH Troubleshooting Chart"WT-36, "NVH Troubleshooting Chart"FAX-5, "NVH Troubleshooting Chart"BR-6, "NVH Troubleshooting Chart"
Possible cause and suspect-
ed parts
Fluid level
Air in hydraulic system
Outer socket ball joint swinging force
Outer socket ball joint rotating torque
Outer socket ball joint end play
Steering fluid leakage
Steering wheel play
Steering gear rack sliding force
Drive belt looseness
Improper steering wheel
Improper installation or looseness of tilt lock lever
Mounting rubber deterioration
Steering column deformation or damage
Improper installation or looseness of steering column
Steering linkage looseness
PROPELLER SHAFT
FRONT FINAL DRIVE
WHEEL HUB
SUSPENSION
TIRES
ROAD WHEEL
DRIVE SHAFT
BRAKES
Symptom
Noise
× × ××××× × × ××××××× ×
Shake ××× × ××××× ×
Vibration ××××× × ××× ×
Shimmy ××× × ×××× ×
Shudder × × ×××× ×
Revision: December 20092009 QX56

STEERING WHEELST-15
< ON-VEHICLE REPAIR >
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ON-VEHICLE REPAIR
STEERING WHEEL
On-Vehicle Inspection and ServiceINFOID:0000000004187602
CHECKING CONDITION OF INSTALLATION
 Check installation condition of steering gear assemb ly, front suspension, axle and steering column.
 Check if movement exists when steering wheel is mo ved up and down, to the left and right and to the axial
direction.
 Check if the nuts for steering gear assembly are loose. Refer to ST-23, "Removal and Installation"
.
CHECKING STEERING WHEEL PLAY
1. Turn tires straight ahead, start engine, then turn steer ing wheel to the left and right lightly, and measure
steering wheel movement on the outer circumference when steering wheel is turned up to the point where
tires start moving.
CHECKING NEUTRAL POSITION ON STEERING WHEEL
 Check neutral position on steering wheel after confirming that front wheel alignment is correct. Refer to FSU-
6, "Front Wheel Alignment".
1. Turn tires straight ahead, check if st eering wheel is in the neutral position.
2. If it is not in the neutral position, remo ve steering wheel and reinstall it correctly.
3. If the neutral position cannot be attained by repositi oning the steering wheel two teeth or less on steering
stem, loosen tie-rod lock nuts of steering outer socket s, then adjust tie-rods by the same amount in the
opposite direction.
CHECKING STEERING WHEEL TURNING FORCE
1. Park vehicle on a level, dry surface and set parking brake.
2. Start engine.
3. Bring power steering fluid up to operating temperature of 60 °– 80 °C (140 °– 176 °F).
4. Tires need to be inflated to specified pressure. Refer to WT-45, "Tire"
.
End play of the axial direction for steering wheel : Refer to
ST-
36, "Steering
Wheel"
LGIA0024E
Steering wheel play on the outer circumference : Refer to ST-36, "Steering
Wheel"
Revision: December 20092009 QX56

WT-1
SUSPENSION
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SECTION WT
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O PCONTENTS
ROAD WHEELS & TIRES
BASIC INSPECTION ....... .............................3
DIAGNOSIS AND REPAIR WORKFLOW ..... .....3
Repair Work Flow ................................................ ......3
INSPECTION AND ADJUSTMENT .....................5
Preliminary Check ............................................... ......5
Transmitter Wake Up Operation ...............................5
ID Registration Procedure .........................................6
FUNCTION DIAGNOSIS ...............................8
TPMS .............................................................. .....8
System Diagram .................................................. ......8
System Description ...................................................8
System Component .................................................10
DIAGNOSIS SYSTEM (BCM) ............................11
CONSULT-III Function (BCM) ............................. ....11
Self-Diagnosis (With CONSULT-III) ........................12
Self-Diagnosis (Without CONSULT-III) ...................13
COMPONENT DIAGNOSIS .........................14
C1708 - C1711 DATA FROM TRANSMITTER
NOT BEING RECEIVED ................................. ....
14
Description .......................................................... ....14
DTC Logic ...............................................................14
Data from Transmitter Not Being Received ............14
Special Repair Requirement ...................................15
C1712 - C1715, C1720 - C1723, C1724 -
C1727 TRANSMITTER MALFUNCTION ....... ....
16
Description .......................................................... ....16
DTC Logic ...............................................................16
Transmitter Malfunction ...........................................16
Special Repair Requirement ...................................17
C1716 - C1719 TRANSMITTER PRESSURE
MALFUNCTION .............................................. ....
18
Description .......................................................... ....18
DTC Logic ...............................................................18
Transmitter Pressure Malfunction ............................18
Special Repair Requirement ................................ ....18
C1729 VEHICLE SPEED SIGNAL ....................19
Description ...............................................................19
DTC Logic ................................................................19
Vehicle Speed Signal ..............................................19
C1735 IGNITION SIGNAL .................................20
Description ...............................................................20
DTC Logic ................................................................20
Diagnosis Procedure ...............................................20
ECU DIAGNOSIS .........................................21
BCM (BODY CONTROL MODULE) .................21
Reference Value .................................................. ....21
Wiring Diagram ........................................................23
Self-Diagnosis (With CONSULT-III) ........................26
Self-Diagnosis (Without CONSULT-III) ...................27
SYMPTOM DIAGNOSIS ..............................29
TPMS .................................................................29
Symptom Table ................................................... ....29
LOW TIRE PRESSURE WARNING LAMP
DOES NOT TURN ON .......................................
30
Low Tire Pressure Warning Lamp Does Not Come
On When Ignition Switch Is Turned On ...................
30
LOW TIRE PRESSURE WARNING LAMP
STAYS ON ........................................................
31
Low Tire Pressure Warning Lamp Stays On When
Ignition Switch Is Turned On ............................... ....
31
LOW TIRE PRESSURE WARNING LAMP
BLINKS .............................................................
32
Low Tire Pressure Warning Lamp Flashes When
Ignition Switch Is Turned On ...................................
32
HAZARD WARNING LAMPS FLASH ..............33
Revision: December 20092009 QX56

WT-36
< SYMPTOM DIAGNOSIS >
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NVH Troubleshooting ChartINFOID:0000000003772398
Use the chart below to help you find the cause of the sy mptom. If necessary, repair or replace these parts.
×: ApplicableReference page
WT-40WT-41WT-45WT-40—
—
WT-45
FA X - 5 , "
NVH Troubleshooting Chart
" (FFD),
RAX-5, "
NVH Troubleshooting Chart
" (RFD)
FA X - 5 , "
NVH Troubleshooting Chart
" (FAX),
FSU-5, "
NVH Troubleshooting Chart
" (FSU)
RAX-5, "
NVH Troubleshooting Chart
" (RAX),
RSU-5, "
NVH Troubleshooting Chart
" (RSU)
Refer to TIRES in this chart.
Refer to ROAD WHEEL in this chart.
BR-6, "
NVH Troubleshooting Chart
"
ST-12, "
NVH Troubleshooting Chart
"
Possible cause and SUSPECTED PARTS
Out-of-round
Imbalance
Incorrect tire pressure
Uneven tire wear
Deformation or damage
Non-uniformity
Incorrect tire size
DIFFERENTIAL
FRONT AXLE AND FRONT SUSPENSION
REAR AXLE AND REAR SUSPENSION
TIRES
ROAD WHEEL
BRAKE
STEERING
Symptom TIRESNoise
× ××××× × × × × ××
Shake × ×××× × × × × ××
Vibration ××× ×××
Shimmy × ×××××× × × × ××
Shudder × ×××× × × × × ××
Poor quality ride or
handling × ×××× × × × ×
ROAD
WHEEL Noise
×× × ××× ×××
Shake ×× × ×× ×××
Shimmy, shudder ×× × ×× ×××
Poor quality ride or
handling ×× ×
×× ×
Revision: December 20092009 QX56