2004 INFINITI QX56 air suspension

STEERING WHEEL
PS-7
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Revision: August 20072004 QX56
STEERING WHEELPFP:48430
On-Vehicle Inspection and ServiceEGS000MQ
CHECKING CONDITION OF INSTALLATION

Check installation condition of steering gear assembly, front suspension, axle and steering column.

Check if movement exists when steering wheel is moved up and down, to the left and right and to the axial
direction.

Check if the mounting nuts for steering gear assembly are loose.
Refer to PS-15, "
POWER STEERING GEAR AND LINKAGE" .
CHECKING STEERING WHEEL PLAY
1. Turn tires straight ahead, start engine, then turn steering 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 steering wheel is in the neutral position.
2. If it is not in the neutral position, remove steering wheel and reinstall it correctly.
3. If the neutral position cannot be attained by repositioning the steering wheel two teeth or less on steering
stem, loosen tie-rod lock nuts of steering outer sockets, 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-33, "
Tire" .
5. Check steering wheel turning force using Tool when steering
wheel has been turned 360° from the neutral position.
6. If steering wheel turning force is out of specification, inspect
steering column. Refer to PS-11, "
INSPECTION AFTER
REMOVAL" .
7. If steering column meets specification, repair steering gear.
Refer to PS-17, "
Disassembly and Assembly" .
CHECKING FRONT WHEEL TURNING ANGLE
When checking front wheel turning angle, refer to FSU-8, "FRONT WHEEL TURNING ANGLE" . End play of the axial direction for steering wheel : 0 mm (0 in)
LGIA0024E
Steering wheel play on the outer circumference : 0 − 35 mm (0 − 1.38 in)
Tool number : J-44372
Steering wheel
turning force: 39 N (4 kg-f, 9 lb-f) or less
WGIA0035E

RAX-4
NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTING
Revision: August 20072004 QX56
NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTINGPFP:00003
NVH Troubleshooting ChartEDS001AS
Use chart below to help you find the cause of the symptom. If necessary, repair or replace these parts.
×: ApplicableReference page
—
RAX-8—
RAX-5—
RFD-5, "
NVH Troubleshooting Chart
"
FAX -4, "
NVH Troubleshooting Chart
" (FAX), FSU-4, "
NVH Troubleshooting Chart
" (FSU)
RSU-5, "
NVH Troubleshooting Chart
"
WT-3, "
NVH Troubleshooting Chart
"
WT-3, "
NVH Troubleshooting Chart
"
PR-3, "
NVH Troubleshooting Chart
"
BR-5, "
NVH Troubleshooting Chart
"
PS-5, "
NVH Troubleshooting Chart
"
Possible cause and SUSPECTED PARTS
Excessive joint angle
Joint sliding resistance
Imbalance
Improper installation, looseness
Parts interference
DIFFERENTIAL
FRONT AXLE AND FRONT SUSPENSION
REAR SUSPENSION
TIRES
ROAD WHEEL
PROPELLER SHAFT
BRAKES
STEERING
SymptomNoise×× ×× ×× ×××××
Shake× × ×× × ×××××
Vibration×× ×× × × × ×
Shimmy×× ×××××
Shudder× × ×× ××
Poor quality ride or handling×× ×× ×× ×

NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTING
RFD-5
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Revision: August 20072004 QX56
NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTINGPFP:00003
NVH Troubleshooting ChartEDS002JJ
Use the chart below to help you find the cause of the symptom. If necessary, repair or replace these parts.
×: Applicable Reference page
RFD-17RFD-19RFD-19RFD-12—
MA-10, "
Fluids and Lubricants
"
PR-3, "
NVH Troubleshooting Chart
"
FA X - 4
(FAX), RAX-4
(RAX), FSU-4
(FSU), RFD-5
(RSU)
WT-3, "
NVH Troubleshooting Chart
"
WT-3, "
NVH Troubleshooting Chart
"
FA X - 4 , "
NVH Troubleshooting Chart
" (front)
RAX-4, "
NVH Troubleshooting Chart
" (rear)
BR-5, "
NVH Troubleshooting Chart
"
PS-5, "
NVH Troubleshooting Chart
"
Possible cause and SUSPECTED PARTS
Rough gear tooth
Improper gear contact
Tooth surfaces worn
Incorrect backlash
Companion flange excessive runout
Improper gear oil
PROPELLER SHAFT
AXLE AND SUSPENSION
TIRES
ROAD WHEEL
DRIVE SHAFT
BRAKES
STEERING
Symptom FINAL DRIVE Noise×××××××××××××

RSU-1
REAR SUSPENSION
E SUSPENSION
CONTENTS
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SECTION RSU
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B
RSU
Revision: August 20072004 QX56 PRECAUTIONS .......................................................... 3
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 3
Precautions for Rear Suspension ............................ 3
Wiring Diagrams and Trouble Diagnosis .................. 3
PREPARATION ........................................................... 4
Commercial Service Tools ........................................ 4
NOISE, VIBRATION, AND HARSHNESS (NVH)
TROUBLESHOOTING ................................................ 5
NVH Troubleshooting Chart ..................................... 5
CAN COMMUNICATION ............................................ 6
System Description .................................................. 6
TROUBLE DIAGNOSIS .............................................. 7
How to Perform Trouble Diagnoses for Quick and
Accurate Repair ....................................................... 7
INTRODUCTION ................................................... 7
CLARIFY CONCERN ............................................ 7
WORK FLOW ........................................................ 8
Component Parts and Harness Connector Location ..... 9
Wiring Diagram — A/SUSP — ............................... 10
Basic Inspection ..................................................... 12
AIR HOSES ......................................................... 12
POWER SYSTEM TERMINAL LOOSENESS
AND BATTERY INSPECTION ............................ 12
CK SUSP INDICATOR LAMP INSPECTION ...... 12
CK SUSP Indicator Lamp Timing ........................... 12
Control Unit Input/Output Signal Standard ............. 12
CONSULT-II Function (AIR LEVELIZER) ............... 13
CONSULT-II OPERATION .................................. 13
WORK SUPPORT ............................................... 14
SELF-DIAGNOSIS .............................................. 14
DATA MONITOR ................................................. 15
ACTIVE TEST ..................................................... 16
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC
ITEMS ....................................................................... 17
Height Sensor System Inspection .......................... 17
Exhaust Valve Solenoid System Inspection ........... 19
Compressor Motor, Compressor Motor Relay and Circuit Inspection .................................................... 20
TROUBLE DIAGNOSES FOR SYMPTOMS ............ 23
Load Leveling Rear Air Suspension System Does
Not Operate ............................................................ 23
CK SUSP Indicator Lamp Stays On When Ignition
Switch Is Turned On ............................................... 24
REAR SUSPENSION ASSEMBLY ........................... 25
Components ........................................................... 25
On-Vehicle Inspection and Service ......................... 26
SHOCK ABSORBER INSPECTION .................... 26
Wheel Alignment Inspection ................................... 27
PRELIMINARY INSPECTION ............................. 27
GENERAL INFORMATION AND RECOMMEN-
DATIONS ............................................................. 27
THE ALIGNMENT PROCESS ............................. 28
CAMBER ............................................................. 28
TOE-IN ................................................................ 28
REAR SUSPENSION MEMBER ............................... 30
Removal and Installation ........................................ 30
REMOVAL ........................................................... 31
INSPECTION AFTER REMOVAL ....................... 32
INSTALLATION ................................................... 33
SHOCK ABSORBER ................................................ 34
Removal and Installation ........................................ 34
REMOVAL ........................................................... 34
INSTALLATION ................................................... 34
INSPECTION AFTER INSTALLATION ................ 34
SUSPENSION ARM .................................................. 35
Removal and Installation ........................................ 35
REMOVAL ........................................................... 35
INSPECTION AFTER REMOVAL ....................... 35
INSTALLATION ................................................... 36
FRONT LOWER LINK .............................................. 37
Removal and Installation ........................................ 37
REMOVAL ........................................................... 37
INSPECTION AFTER REMOVAL ....................... 37
INSTALLATION ................................................... 38

RSU-2Revision: August 20072004 QX56 REAR LOWER LINK & COIL SPRING ..................... 39
Removal and Installation ........................................ 39
REMOVAL ........................................................... 39
INSPECTION AFTER REMOVAL ........................ 40
INSTALLATION .................................................... 40
STABILIZER BAR ..................................................... 41
Removal and Installation ........................................ 41
REMOVAL ........................................................... 41
INSTALLATION .................................................... 41
Inspection ............................................................... 41
REAR LOAD LEVELING AIR SUSPENSION COM-
PRESSOR ASSEMBLY ............................................ 42
Removal and Installation ........................................ 42
REMOVAL ........................................................... 42
INSTALLATION .................................................... 43HEIGHT SENSOR .....................................................44
Removal and Installation .........................................44
REMOVAL ............................................................44
INSTALLATION ....................................................45
CONTROL UNIT ........................................................46
Removal and Installation .........................................46
REMOVAL ............................................................46
INSTALLATION ....................................................46
Initialization Procedure ............................................46
SERVICE DATA AND SPECIFICATIONS (SDS) ......47
Wheel Alignment .....................................................47
Ball Joint .................................................................47
Wheelarch Height (Unladen*
1 ) ...............................48

PRECAUTIONS
RSU-3
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RSU
Revision: August 20072004 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EES0010X
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 severity 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 whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WA RN ING:

To avoid rendering the SRS inoperative, 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 per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Precautions for Rear SuspensionEES0010Y

When installing the rubber bushings, the final tightening must be done under unladen condition and with
the tires on level ground. Oil will shorten the life of the rubber bushings, so wipe off any spilled oil immedi-
ately.

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.
Wiring Diagrams and Trouble DiagnosisEES0010Z
When you read wiring diagrams, refer to the following:

GI-15, "How to Read Wiring Diagrams".

PG-4, "POWER SUPPLY ROUTING CIRCUIT" for power distribution circuit.
When you perform trouble diagnosis, refer to the following:

GI-11, "How to Follow Trouble Diagnoses".

GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident".

NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTING
RSU-5
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RSU
Revision: August 20072004 QX56
NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTINGPFP:00003
NVH Troubleshooting ChartEES00111
Use chart below to help you find the cause of the symptom. If necessary, repair or replace these parts.
×: Applicable Reference page
RSU-25RSU-34
—
—
—
RSU-25
RSU-27RSU-41
PR-3, "
NVH Troubleshooting Chart
"
RFD-5, "
NVH Troubleshooting Chart
"
FAX -4, "
NVH Troubleshooting Chart
" (FAX)
FSU-4, "
NVH Troubleshooting Chart
" (FSU)
WT-3, "
NVH Troubleshooting Chart
"
WT-3, "
NVH Troubleshooting Chart
"
RAX-4, "
NVH Troubleshooting Chart
"
PS-5, "
NVH Troubleshooting Chart
"
BR-5, "
NVH Troubleshooting Chart
"
Possible cause and SUSPECTED PARTS
Improper installation, looseness
Shock absorber deformation, damage or deflection
Bushing or mounting deterioration
Parts interference
Spring fatigue
Suspension looseness
Incorrect wheel alignment
Stabilizer bar fatigue
PROPELLER SHAFT
DIFFERENTIAL
FRONT AXLE AND FRONT SUSPENSION
TIRES
ROAD WHEEL
DRIVE SHAFT
BRAKES
STEERING
SymptomNoise×××××× ××× ×××××
Shake×××× × × × ×××××
Vibration××××× × × × × ×
Shimmy×××× × × ×× ××
Shudder ××× × ×× ××
Poor quality ride or handling××××× ×× × ××

TROUBLE DIAGNOSIS
RSU-7
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RSU
Revision: August 20072004 QX56
TROUBLE DIAGNOSISPFP:00000
How to Perform Trouble Diagnoses for Quick and Accurate RepairEES00113
INTRODUCTION
The rear load leveling air suspension system uses an electronic con-
trol unit to control major functions. The control unit accepts input sig-
nals from the height sensor and controls compressor and exhaust
valve operation.
It is much more difficult to diagnose a rear load leveling air suspen-
sion system problem that occurs intermittently rather than continu-
ously. Most intermittent problems are caused by poor electrical
connections or faulty wiring. In this case, careful checking of suspi-
cious circuits may help prevent the replacement of good parts.
Before undertaking actual checks, take just a few minutes to talk with
a customer who approaches with an air suspension system com-
plaint. The customer is a very good source of information on such
problems, especially intermittent ones. Through discussion with the
customer, find out what symptoms are present and under what con-
ditions they occur.
Start your diagnosis by looking for basic mechanical problems first.
This is one of the best ways to troubleshoot concerns on an air sus-
pension system equipped vehicle. Also check related Service Bulle-
tins for information.
CLARIFY CONCERN

A customer's description of a vehicle concern may vary depend-
ing on the individual. It is important to clarify the customer's con-
cern.

Ask the customer about what symptoms are present under what
conditions. Use this information to reproduce the symptom.
SEF 2 33 G
SEF 2 34 G
SBR3 39 B