height INFINITI QX56 2007 Factory Repair Manual

RSU-1
SUSPENSION
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SECTION RSU
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RSU
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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-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-11
< SERVICE INFORMATION >
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POWER SYSTEM TERMINAL LOOSENESS AND BATTERY INSPECTION
Make sure the battery positive cable, negative cable and ground connection are not loose. In addition, make
sure the battery is sufficiently charged.
CK SUSP INDICATOR LAMP INSPECTION
1. Make sure the CK SUSP indicator lamp turns on for approximately 2 seconds when the ignition switch is
turned ON. If it does not, check the combination meter. Refer to DI-5
.
2. Make sure the lamp turns off approximately 2 seconds after the ignition switch is turned ON. If the lamp
does not turn off, conduct self-diagnosis of the suspension control unit.
3. After conducting the self-diagnosis, be sure to erase the error memory. Refer to RSU-11, "
CONSULT-II
Function (AIR LEVELIZER)" .
Chek Suspension Indicator Lamp TimingINFOID:0000000003532661
X: ON
—: OFF
Control Unit Input/Output Signal StandardINFOID:0000000003532662
CONSULT-II Function (AIR LEVELIZER)INFOID:0000000003532663
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II START PROCEDURE
Refer to GI-36, "CONSULT-II Start Procedure".
ConditionCK SUSP
indicator lampRemarks
Ignition switch OFF – –
Ignition switch ON X Turns off after approximately 2 seconds.
Te r m i n a l
No.Wire color Item ConditionVoltage (V)
(Approx.)
1 V Compressor relay output
Ignition switch ON or STARTBattery voltage
3 W Height sensor signal input 0.2V - 4.8V
5 R Reference voltage 5V
6 G/R Ignition power
Battery voltage
7W/LBattery power —
8 G/W Diagnostic K-line — —
9 SB Exhaust valve output Ignition switch ON or START Battery voltage
10 BR Warning lamp output — —
14 L Height sensor ground — —
15 BR/W Generator L signal input Engine running —
16 B Suspension control unit ground — 0V
AIR LEVELIZER
diagnostic modeDescription
WORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the BCM for setting the status
suitable for required operation, input/output signals are received from the BCM and received data is
displayed.
SELF-DIAG RESULTS Displays suspension control unit self-diagnosis results.
DATA MONITOR Displays suspension control unit input/output data in real time.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
ECU PART NUMBER Suspension control unit part number can be read.

RSU-12
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
SELF-DIAGNOSIS
Display Item List
WORK SUPPORT
Display Item List
DATA MONITOR
Display Item List
Self-diagnostic item Malfunction detecting condition Check system
Vehicle height sensor
[C1801]Vehicle height sensor voltage is less than 0.2V or greater than
4.8V for more than 60 seconds.Refer to RSU-14, "
Height
Sensor System Inspection" .
Compressor relay
[C1802]1. Driving transistor for compressor relay is off and monitor
voltage continues high level for more than 10 seconds.
2. Driving transistor for compressor relay is on and monitor
voltage continues low level for more than 5 seconds.Refer to RSU-17, "
Compres-
sor Motor, Compressor Motor
Relay and Circuit Inspection"
.
Exhaust solenoid
[C1803]1. Driving transistor for exhaust solenoid is off and monitor volt-
age continues high level for more than 10 seconds.
2. Driving transistor for exhaust solenoid is on and monitor volt-
age continues low level for more than 5 seconds.Refer to RSU-15, "
Exhaust
Valve Solenoid System In-
spection" .
Vehicle height adjusting trouble
(compressor)
[C1804]Continuous compressor relay ON time is more than 120 seconds.Refer to RSU-17, "
Compres-
sor Motor, Compressor Motor
Relay and Circuit Inspection"
.
Vehicle height adjusting trouble
(exhaust solenoid)
[C1805]Continuous exhaust solenoid ON time is more than 120 seconds.Refer to RSU-15, "
Exhaust
Valve Solenoid System In-
spection" .
Vehicle height sensor locking trou-
ble
[C1806]Output sensor voltage variation ±0.02V is more than 100 hour
when vehicle height range is normal.Refer to RSU-14, "
Height
Sensor System Inspection".
Sensor 5V trouble
[C1807]Sensor reference voltage is less than 0.8V or more than 6V for 20
seconds.Refer to RSU-14, "
Height
Sensor System Inspection".
Integral time trouble by supplying
air
[C1808]Integral discontinuous time on the compressor is more than 180
seconds.Refer to RSU-17, "
Compres-
sor Motor, Compressor Motor
Relay and Circuit Inspec-
tion".
Item Description Condition
STANDARD HEIGHT LEVELResets the vehicle height to the initialization flag set-
ting stored in the suspension control unit.Vehicle unladen RSU-44, "
Wheelarch Height
(Unladen*1)" , set in a horizontal position and
not moving.
NOTE:
Do not take your eyes off the vehicle while
CONSULT-II is processing.
ADJUST HEIGHT INISets the height initialization flag in the suspension
control unit when the control unit has been replaced
or when the initialization flag has been cleared using
the "CLEAR HEIGHT INI" procedure.Vehicle unladen RSU-44, "
Wheelarch Height
(Unladen*1)" . Move vehicle forward and back-
ward approx. 5 m (16.4 ft) and rock vehicle from
side to side.
NOTE:
Do not move vehicle while CONSULT-II is pro-
cessing.
CLEAR HEIGHT INIClears the initialization flag in the suspension control
unit.Vehicle unladen RSU-44, "
Wheelarch Height
(Unladen*1)" .

RSU-14
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Height Sensor System InspectionINFOID:0000000003532664
INSPECTION PROCEDURE
1.SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
YES >> GO TO 3.
NO >> GO TO 2.
2.DATA MONITOR CHECK
Conduct data monitor of "HEIGT SEN" to check if the status is normal.
OK or NG
OK >> Inspection End.
NG >> GO TO 3.
3.CONNECTOR INSPECTION
1. Disconnect suspension control unit connector B3 and height sensor C8.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace as necessary.
4.CHECK HEIGHT SENSOR POWER
1. Reconnect the suspension control unit connector.
2. Turn the ignition switch ON.
3. Check voltage between height sensor connector C8 terminal 1
and ground.
OK or NG
OK >> GO TO 5.
NG >> Check harness or connector for open or short. If OK,
replace suspension control unit. Refer to RSU-42
.
5.CHECK HEIGHT SENSOR GROUND
1. Turn ignition switch OFF.
Self-diagnosis results
C1801
C1806
C1807
HEIGT SEN 0.2V - 4.8V
Voltage : Approx. 5V
WEIA0084E

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
RSU-15
< SERVICE INFORMATION >
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2. Check continuity between height sensor connector C8 terminal
3 and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6.CHECK HEIGHT SENSOR SIGNAL CIRCUIT
1. Disconnect suspension control unit connector.
2. Check continuity between height sensor connector C8 terminal
2 and suspension control unit connector B3 terminal 3.
3. Check continuity between height sensor connector C8 terminal
2 and ground.
OK or NG
OK >> Replace the height sensor. Refer to RSU-40.
NG >> Repair harness or connector.
Exhaust Valve Solenoid System InspectionINFOID:0000000003532665
INSPECTION PROCEDURE
1.SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
YES >> If code C1803 was retrieved during self-diagnosis, GO TO 3. If code C1805 was retrieved during
self-diagnosis, GO TO 2.
NO >> Inspection End.
2.CHECK SYSTEM OPERATION
1. Load vehicle to standard laden condition (with driver, front passenger, 2 passengers in second row seats
and no cargo).
2. Conduct active test of "COMPRESSOR" to raise vehicle ride height to +20mm.
CAUTION:3 - Ground Continuity should exist.
WEIA0085E
2 - 3 Continuity should exist.
WEIA0086E
2 - Ground Continuity should not exist.
WEIA0087E
Self-diagnosis results
C1803
C1805

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
RSU-17
< SERVICE INFORMATION >
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5. Check continuity between suspension air compressor connector
C9 terminal 1 and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-42.
NG >> Repair harness or connector.
Compressor Motor, Compressor Motor Relay and Circuit InspectionINFOID:0000000003532666
INSPECTION PROCEDURE
1.SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
YES >> If code C1802 was retrieved during self-diagnosis, GO TO 3. If code C1804 or C1808 was
retrieved during self-diagnosis, GO TO 2.
NO >> Inspection End.
2.CHECK SYSTEM OPERATION
1. Load vehicle to standard laden condition (with driver, front passenger, 2 passengers in second row seats
and no cargo).
2. Conduct active test of "EXHAUST SOLENOID" to lower vehicle ride height to -20mm.
3. Return the rear load leveling air suspension system to normal operating mode.
4. Check self-diagnostic results.
Is code C1804 or C1808 displayed again?
YES >> GO TO 3.
NO >> Inspection End.
3.CONNECTOR INSPECTION
1. Disconnect suspension control unit connector B3 and suspension air compressor C9.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> If code C1804 or C1808 was retrieved during self-diagnosis, GO TO 4. If code C1802 was
retrieved during self-diagnosis, GO TO 6.
NG >> Repair or replace as necessary.
4.AIR HOSE INSPECTION
Inspect for pinched or damaged air hoses between the suspension air reservoir and each load leveling rear air
suspension shock absorber.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace as necessary.
5.SUSPENSION AIR COMPRESSOR INSPECTION1 - Ground Continuity should exist.
WEIA0089E
Self-diagnosis results
C1802
C1804
C1808

RSU-22
< SERVICE INFORMATION >
REAR SUSPENSION ASSEMBLY
Rear Load Leveling Air Suspension System
On-Vehicle Inspection and ServiceINFOID:0000000003532670
Check all of the component mountings for any excessive looseness, or back lash. Check the components for
any excessive wear, damage, or abnormal conditions. Repair or replace the components as necessary.
SHOCK ABSORBER INSPECTION
• Check the shock absorbers for any air leaks or damage, and replace as necessary.
• Check the hoses for any air leaks or damage, and replace as necessary.
10. Shock absorber 11. Suspension arm 12. Lower rubber seat
13. Coil spring 14. Upper rubber seat 15. Rear suspension member
16. Spare tire bracket 17. Bound bumper
AWEIA0076ZZ
1. Rear load leveling air suspension
hose, RH2. Shock absorber, RH 3. Height sensor
4. Rear load leveling air suspension
hose, LH5. Shock absorber, LH 6. Rear load leveling air suspension
compressor assembly
⇐Front

REAR SUSPENSION ASSEMBLY
RSU-23
< SERVICE INFORMATION >
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Wheel AlignmentInspectionINFOID:0000000003532671
Rear Wheel Alignment Adjusting Bolts
PRELIMINARY INSPECTION
WARNING:
Always adjust the alignment with the vehicle on a flat surface. Use CONSULT-II “EXHAUST SOLE-
NOID” active test to release the air pressure from the rear load leveling air suspension system.
NOTE:
If alignment is out of specification, inspect and replace any damaged or worn rear suspension parts before
making any adjustments.
1. Check and adjust the wheel alignment with the vehicle under unladen conditions. “Unladen conditions”
means that the fuel, coolant, and lubricant are full; and that the spare tire, jack, hand tools and mats are in
their designated positions.
2. Check the tires for incorrect air pressure and excessive wear.
3. Check the wheels for runout and damage. Refer to WT-5, "
Inspection" .
4. Check the wheel bearing axial end play.
5. Check the shock absorbers. Refer to RSU-30, "
Removal and Installation" .
6. Check each mounting point of the suspension components for any excessive looseness or damage.
7. Check each link, arm, and the rear suspension member for any damage.
8. Check the vehicle height. Refer to RSU-44, "
Wheelarch Height (Unladen*1)" .
• If vehicle height is not within ± 10 mm (0.39 in) of the specification, perform the control unit initialization
procedure. Refer to RSU-42, "
Initialization Procedure" .
GENERAL INFORMATION AND RECOMMENDATIONS
1. A Four-Wheel Thrust Alignment should be performed.
• This type of alignment is recommended for any NISSAN vehicle.
• The four-wheel “thrust” process helps ensure that the vehicle is properly aligned and the steering wheel
is centered.
• The alignment machine itself should be capable of accepting any NISSAN vehicle.
• The alignment machine should be checked to ensure that it is level.
2. Make sure the alignment machine is properly calibrated.
• Your alignment machine should be regularly calibrated in order to give correct information.
WEIA0102E
1. Rear lower link adjusting bolt, LH 2. Front lower link adjusting bolt, LH 3. Front lower link adjusting bolt, RH
4. Rear lower link adjusting bolt, RH
Axial end play : 0 mm (0 in)

RSU-24
< SERVICE INFORMATION >
REAR SUSPENSION ASSEMBLY
• Check with the manufacturer of your specific alignment machine for their recommended Service/Cali-
bration Schedule.
THE ALIGNMENT PROCESS
IMPORTANT: Use only the alignment specifications listed in this Service Manual. Refer to FSU-19, "Wheel
Alignment (Unladen*1) *6" .
1. When displaying the alignment settings, many alignment machines use “indicators”: (Green/red, plus or
minus, Go/No Go). Do NOT use these indicators.
• The alignment specifications programmed into your alignment machine that operate these indicators
may not be correct.
• This may result in an ERROR.
2. Some newer alignment machines are equipped with an optional “Rolling Compensation” method to “com-
pensate” the sensors (alignment targets or head units). Do NOT use this “Rolling Compensation”
method.
• Use the “Jacking Compensation” method. After installing the alignment targets or head units, raise the
vehicle and rotate the wheels 1/2 turn both ways.
• See Instructions in the alignment machine you are using for more information.
CAMBER
1. Measure camber of both the right and left wheels with a suitable
alignment gauge and adjust as necessary to specification.
2. If outside of the specified value, adjust the camber using the
adjusting bolt in the front lower link.
CAUTION:
After adjusting the camber then check the toe-in.
NOTE:
Camber changes about 0° 5' with each graduation of the adjust-
ing bolt.
3. Tighten the adjusting bolt nuts to specification.
TOE-IN
1. Bounce the rear of the vehicle up and down two to three times to stabilize the vehicle height. Refer to
FSU-20, "
Wheelarch Height (Unladen*1)" .
2. Push the vehicle straight ahead about 5 m (16 ft).
3. Put a mark on the base line of the tread (rear side) of both of the
tires at the same height as the center of the hub. This will be the
measuring points.
4. Measure the distance “A” (rear side) across from tire to tire.Camber : Refer to FSU-19, "
Wheel Alignment (Unlad-
en*1) *6" .
SRA096A
LEIA0041E
SFA614B