2007 INFINITI QX56 suspension

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
RSU-17
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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.
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Self-diagnosis results
C1802
C1804
C1808

RSU-18
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Apply 12V to suspension air compressor terminal 2 and ground to
suspension air compressor terminal 1.
OK or NG
OK >> GO TO 6.
NG >> Replace the suspension air compressor. Refer to RSU-
38.
6.CHECK SUSPENSION AIR COMPRESSOR POWER AND GROUND
1. Connect suspension control unit connector B3.
2. Turn the ignition switch ON.
3. Check voltage between suspension air compressor connector
C9 terminal 2 and ground.
4. Turn ignition switch OFF.
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.System air pressure should vent.
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Voltage : Approx. 12V
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1 - Ground Continuity should exist.
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TROUBLE DIAGNOSES FOR SYMPTOMS
RSU-19
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TROUBLE DIAGNOSES FOR SYMPTOMS
Load Leveling Rear Air Suspension System Does Not OperateINFOID:0000000003532667
1.CHECK WARNING LAMP ACTIVATION
Make sure warning lamp remains off while driving.
OK or NG
OK >> GO TO 2.
NG >> Carry out self-diagnosis. Refer to RSU-11, "
CONSULT-II Function (AIR LEVELIZER)" .
2.CHECK FUSES AND FUSIBLE LINK
Check that the following fuses and fusible link are not blown.
OK or NG
OK >> GO TO 3.
NG >> If fuse or fusible link is blown, be sure to eliminate cause of malfunction before installing new fuse
or fusible link.
3.CHECK SUSPENSION CONTROL UNIT POWER AND GROUND
1. Turn the ignition switch ON.
2. Check voltage between suspension control unit connector B3
terminal 6 and ground and between suspension control unit con-
nector B3 terminal 7 and ground.
3. Turn the ignition switch OFF.
4. Check continuity between suspension control unit connector B3
terminal 16 and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4.CHECK GENERATOR SIGNAL INPUT
1. Start the engine.
Unit Terminals Signal name Fuse and fusible link No.
Suspension control unit6 Ignition switch ON or START 12 (10A)
7
Battery power29 (10A)
Compressor motor relay 5 g (30A)
Combination meter24 Ignition switch ON or START 14 (10A)
8 Battery power 19 (10A)
Voltage : Approx. 12V
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16 - Ground Continuity should exist.
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RSU-20
< SERVICE INFORMATION >
TROUBLE DIAGNOSES FOR SYMPTOMS
2. Check voltage between suspension control unit connector B3
terminal 15 and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-42.
NG >> Repair the circuit.
Chek Suspension Indicator Lamp Stays On When Ignition Switch Is Turned On
INFOID:0000000003532668
1.CARRY OUT SELF-DIAGNOSIS
Carry out self-diagnosis. Refer to RSU-11, "
CONSULT-II Function (AIR LEVELIZER)".
Are malfunctions detected in self-diagnosis?
YES >> Refer to RSU-11, "CONSULT-II Function (AIR LEVELIZER)" .
NO >> Refer to DI-26
. Voltage : Approx. 12V
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REAR SUSPENSION ASSEMBLY
RSU-21
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REAR SUSPENSION ASSEMBLY
ComponentINFOID:0000000003532669
Rear Suspension
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1. Seat belt latch anchor 2. Stabilizer bar bushing 3. Stabilizer bar clamp
4. Stabilizer bar 5. Connecting rod 6. Front lower link
7. Knuckle 8. Bushing 9. Rear lower link

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
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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
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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.
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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" .
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