service INFINITI QX56 2007 Factory Service Manual

RSU-1
SUSPENSION
C
D
F
G
H
I
J
K
L
M
SECTION RSU
A
B
RSU
N
O
PCONTENTS
REAR SUSPENSION
SERVICE INFORMATION ............................2
PRECAUTIONS ...................................................2
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ...................................................................
2
Precaution for Rear Suspension ...............................2
PREPARATION ...................................................3
Commercial Service Tool ..........................................3
NOISE, VIBRATION AND HARSHNESS
(NVH) TROUBLESHOOTING .............................
4
NVH Troubleshooting Chart ......................................4
CAN COMMUNICATION .....................................5
System Description ...................................................5
TROUBLE DIAGNOSIS ......................................6
How to Perform Trouble Diagnosis for Quick and
Accurate Repair ........................................................
6
Component Parts and Harness Connector Loca-
tion ............................................................................
8
Wiring Diagram - A/SUSP - .......................................9
Basic Inspection ......................................................10
Chek Suspension Indicator Lamp Timing ...............11
Control Unit Input/Output Signal Standard ..............11
CONSULT-II Function (AIR LEVELIZER) ...............11
TROUBLE DIAGNOSIS FOR SELF-DIAG-
NOSTIC ITEMS ..................................................
14
Height Sensor System Inspection ...........................14
Exhaust Valve Solenoid System Inspection ............15
Compressor Motor, Compressor Motor Relay and
Circuit Inspection .....................................................
17
TROUBLE DIAGNOSES FOR SYMPTOMS ......19
Load Leveling Rear Air Suspension System Does
Not Operate .............................................................
19
Chek Suspension Indicator Lamp Stays On When
Ignition Switch Is Turned On ...................................
20
REAR SUSPENSION ASSEMBLY ...................21
Component ..............................................................21
On-Vehicle Inspection and Service .........................22
Wheel AlignmentInspection .....................................23
REAR SUSPENSION MEMBER .......................26
Removal and Installation .........................................26
SHOCK ABSORBER ........................................30
Removal and Installation .........................................30
SUSPENSION ARM ..........................................31
Removal and Installation .........................................31
FRONT LOWER LINK .......................................33
Removal and Installation .........................................33
REAR LOWER LINK & COIL SPRING .............35
Removal and Installation .........................................35
STABILIZER BAR .............................................37
Removal and Installation .........................................37
REAR LOAD LEVELING AIR SUSPENSION
COMPRESSOR ASSEMBLY ............................
38
Removal and Installation .........................................38
HEIGHT SENSOR .............................................40
Removal and Installation .........................................40
CONTROL UNIT ................................................42
Removal and Installation .........................................42
Initialization Procedure ............................................42
SERVICE DATA AND SPECIFICATIONS
(SDS) .................................................................
43
Wheel Alignment .....................................................43
Ball Joint ..................................................................43
Wheelarch Height (Unladen*1) ................................44

RSU-2
< SERVICE INFORMATION >
PRECAUTIONS
SERVICE INFORMATION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000003532652
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.
WARNING:
• 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 performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal
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 har-
ness connectors.
Precaution for Rear SuspensionINFOID:0000000003532653
• 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 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.

PREPARATION
RSU-3
< SERVICE INFORMATION >
C
D
F
G
H
I
J
K
L
MA
B
RSU
N
O
P
PREPARATION
Commercial Service ToolINFOID:0000000003532654
Tool nameDescription
Power tool• Removing wheel nuts
• Removing brake caliper assembly
• Removing rear suspension component
parts
PBIC0190E

RSU-4
< SERVICE INFORMATION >
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NVH Troubleshooting ChartINFOID:0000000003532655
Use chart below to help you find the cause of the symptom. If necessary, repair or replace these parts.
×: ApplicableReference page
RSU-21RSU-30
—
—
—
RSU-21
RSU-23RSU-37
PR-3, "
NVH Troubleshooting Chart
"
RFD-7, "
NVH Troubleshooting Chart
"
FAX-4, "
NVH Troubleshooting Chart
"
FSU-4, "
NVH Troubleshooting Chart
"
WT-4, "
NVH Troubleshooting Chart
"
WT-4, "
NVH Troubleshooting Chart
"
FAX-4, "
NVH Troubleshooting Chart
"
BR-4, "
NVH Troubleshooting Chart
"
PS-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
FRONT SUSPENSION
TIRES
ROAD WHEEL
DRIVE SHAFT
BRAKES
STEERING
SymptomNoise×××××× ××× ××××××
Shake×××× × × × ××××××
Vibration××××× × × ×× × ×
Shimmy×××× × × ××× ××
Shudder ××× × ××× ××
Poor quality ride or handling××××× ×× × ×××

CAN COMMUNICATION
RSU-5
< SERVICE INFORMATION >
C
D
F
G
H
I
J
K
L
MA
B
RSU
N
O
P
CAN COMMUNICATION
System DescriptionINFOID:0000000003532656
Refer to EC-32 .

RSU-6
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
How to Perform Trouble Diagnosis for Quick and Accurate RepairINFOID:0000000003532657
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 depending
on the individual. It is important to clarify the customer's concern.
• Ask the customer about what symptoms are present under what
conditions. Use this information to reproduce the symptom.
SEF233G
SEF234G
SBR339B

TROUBLE DIAGNOSIS
RSU-7
< SERVICE INFORMATION >
C
D
F
G
H
I
J
K
L
MA
B
RSU
N
O
P
WORK FLOW
WEIA0077E

RSU-8
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Component Parts and Harness Connector Location
INFOID:0000000003532658
WEIA0140E

TROUBLE DIAGNOSIS
RSU-9
< SERVICE INFORMATION >
C
D
F
G
H
I
J
K
L
MA
B
RSU
N
O
P
Wiring Diagram - A/SUSP -INFOID:0000000003532659
WEWA0049E

RSU-10
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Basic Inspection
INFOID:0000000003532660
AIR HOSES
1. Check for pinched or damaged air hoses between the suspension air reservoir and each load leveling rear
air suspension shock absorber. Reposition, repair or replace hoses as necessary.
2. Check the air hose connections at the suspension air reservoir and at the shock absorbers for leaks. If
connections are leaking, repair or replace hoses as necessary.
WEWA0070E