2008 INFINITI QX56 suspension

RSU-20
< REMOVAL AND INSTALLATION >
REAR LOWER LINK & COIL SPRING
REAR LOWER LINK & COIL SPRING
Removal and InstallationINFOID:0000000004900761
REMOVAL
1. Remove the wheel and tire assembly using power tool. Refer to WT-48, "Rotation" .
2. Use CONSULT-III "EXHAUST SOLENOID" active test to release the air pressure from the rear load level-
ing air suspension system.
3. For removing the LH rear lower link and coil spring, remove the height sensor arm bracket bolt from the LH rear lower link.
4. Remove speed sensor harness and brackets from rear lower link.
5. Set a suitable jack to relieve the coil spring tension from the rear lower link.
WARNING:
Do not compress the coil sp ring when setting the jack.
6. Loosen the rear lower link adjusting bolt and nut connected to the rear suspension member, using power tool.
7. Remove the rear lower link bolt and nut from the knuckle using power tool.
LEIA0080E
LEIA0077E
LEIA0009E
LEIA0077E
Revision: March 2010 2008 QX56

REAR LOWER LINK & COIL SPRINGRSU-21
< REMOVAL AND INSTALLATION >
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8. Slowly lower the suitable jack to release the coil spring tension. Then remove the upper rubber seat, coil spring, and lower rubber seat from the rear lower link.
9. Remove the rear lower link adjusting bolt and nut from the rear suspension member using power tool, then remove the rear
lower link.
INSPECTION AFTER REMOVAL
Check the coil spring and rubber seats for deformation, cracks, or other damage and replace if necessary.
INSTALLATION
Installation is in the reverse order of removal.
• Tighten the nuts and bolts to specification. Refer to RSU-9, "
Component" .
• When installing the upper and lower rubber seats for the rear coil springs, the arrow embossed on the rubber seats must point out
toward the wheel and tire assembly.
• After installing the rear lower link and coil spring, check the wheel alignment and adjust if necessary. Refer to RSU-6, "
Wheel Align-
ment Inspection"
LEIA0009E
LEIA0076E
Revision: March 2010 2008 QX56

REAR LOAD LEVELING AIR SUSPENSION COMPRESSOR ASSEMBLYRSU-23
< REMOVAL AND INSTALLATION >
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REAR LOAD LEVELING AIR SUSPENSION COMPRESSOR ASSEMBLY
Removal and InstallationINFOID:0000000004900763
Rear Load Leveling Air Suspension System
REMOVAL
1. Use CONSULT-III "EXHAUST SOLENOID" active test to release the air pressure from the rear load level-
ing air suspension system.
2. Disconnect the electrical connectors for the rear load leveling air suspension compressor assembly.
3. Unclip the rubber cover to access the rear load leveling air suspension compressor assembly.
4. Disconnect the rear load leveling air suspension hoses at the rear load leveling air suspension compressor assembly.
• To disconnect the hoses, push in on the lock ring using a suit-
able tool and pull the hose out.
AWEIA0054GB
1. Rear load leveling air suspension
hose, RH 2. Shock absorber, RH 3. Height sensor
4. Rear load leveling air suspension hose, LH 5. Shock absorber, LH
6. Rear load leveling air suspension
compressor assembly
Front
LEIA0074E
Revision: March 2010 2008 QX56

RSU-24
< REMOVAL AND INSTALLATION >
REAR LOAD LEVELING AIR SUSPENSION COMPRESSOR ASSEMBLY
5. Remove the four bolts that mount the rear load leveling air sus-
pension compressor assembly to the underbody.
INSTALLATION
Installation is in the reverse order of removal.
• To connect the rear load leveling air suspension hoses, the lockring must be fully seated in the fitt ing. Insert the hose “B” into the
lock ring “A” until the lock ring “A” is touching the hose “B” as
shown. Pull on the hose to check that it is securely inserted.
LEIA0090E
LEIA0078E
Revision: March 2010 2008 QX56

CONTROL UNITRSU-25
< REMOVAL AND INSTALLATION >
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CONTROL UNIT
Removal and InstallationINFOID:0000000004900764
REMOVAL
1. Remove the rear LH interior trim panel. Refer to INT-14, "Removal and Installation" .
2. Disconnect the battery negative terminal.
3. Disconnect the suspension control unit electrical connector.
4. Remove the two bolts and remove the suspension control unit.
INSTALLATION
Installation is in the reverse order of removal.
Initialization ProcedureINFOID:0000000004900765
1. If control unit has been replaced, proceed to step 2. If control unit has not been replaced, use CONSULT-
III “CLEAR HEIGHT INI” work support function to cl ear initialization flag and value. The CK SUSP warning
lamp should illuminate. Using CONSULT-III “EXHAUST SOLENOID” active test, release the air pressure
from the rear load leveling air suspension system.
2. Roll vehicle forward and backward.
3. Use CONSULT-III “ADJUST HEIGHT INI” work support function to set initialization condition.
4. Confirm that CK SUSP warning lamp is OFF.
LEIA0100E
Suspension control unit bolt s : 6 N·m (0.6 kg-m, 53 in-lb)
Revision: March 2010 2008 QX56

RSU-26
< REMOVAL AND INSTALLATION >
HEIGHT SENSOR
HEIGHT SENSOR
Removal and InstallationINFOID:0000000004900766
Rear Load Leveling Air Suspension System
REMOVAL
1. Use CONSULT-III “EXHAUST SOLENOID” active test to release the air pressure from the rear load level-
ing air suspension system.
2. Disconnect the electrical connector for the height sensor.
3. Remove the two height sensor bolts and height sensor arm bracket bolt.
4. Remove the height sensor.
INSTALLATION
Installation is in the reverse order of removal.
AWEIA0054GB
1. Rear load leveling air suspension hose, RH 2. Shock absorber, RH
3. Height sensor
4. Rear load leveling air suspension hose, LH 5. Shock absorber, LH
6. Rear load leveling air suspension
compressor assembly
Front
LEIA0080E
Revision: March 2010 2008 QX56

SERVICE DATA AND SPECIFICATIONS (SDS)RSU-29
< SERVICE DATA AND SPECIFICATIONS (SDS)
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Wheelarch Height (Unladen*1)INFOID:0000000004918900
Unit: mm (in)
*1: Fuel, engine coolant and engine oil full. Spare tire, jack, hand tools and mats in designated positions.
*2: Verify the vehicle height. If vehicle height is not within ± 10 mm (0.39 in) of the specification, perform the control unit initialization pro-
cedure. Refer to SCS-7, "
CONSULT-III Function" .
Suspension type
Air leveling*
2
Applied model2WD 4WD
Front wheelarch height (Hf) 920
(36.22) 937
(36.89)
Rear wheelarch height (Hr) 917
(36.10) 937
(36.89)
LEIA0085E
Revision: March 2010 2008 QX56

SCS-1
SUSPENSION
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SECTION SCS
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SUSPENSION CONTROL SYSTEM
BASIC INSPECTION ....... .............................3
DIAGNOSIS AND REPAIR WORKFLOW ..... .....3
Work Flow ........................................................... ......3
FUNCTION DIAGNOSIS ...............................5
SUSPENSION CONTROL SYSTEM .............. .....5
System Diagram .................................................. ......5
System Description ...................................................5
Component Parts Location ........................................6
Component Description .............................................6
DIAGNOSIS SYSTEM (SUSPENSION CON-
TROL UNIT) .........................................................
7
CONSULT-III Function ..............................................7
COMPONENT DIAGNOSIS ..........................9
C1801 VEHICLE HEIGHT SENSOR .............. .....9
Description .......................................................... ......9
DTC Logic .................................................................9
Diagnosis Procedure ................................................9
C1802 COMPRESSOR RELAY .........................10
Description ..............................................................10
DTC Logic ...............................................................10
Diagnosis Procedure ..............................................10
C1803 EXHAUST SOLENOID ...........................11
Description ..............................................................11
DTC Logic ...............................................................11
Diagnosis Procedure ..............................................11
C1804 HEIGHT ADJUSTING MALFUNCTION
(COMPRESSOR) ............................................ ....
12
Description .......................................................... ....12
DTC Logic ...............................................................12
Diagnosis Procedure ..............................................12
C1805 HEIGHT ADJUSTING MALFUNCTION
(EXH SOLENOID) ..............................................
13
Description ........................................................... ....13
DTC Logic ................................................................13
Diagnosis Procedure ..............................................13
C1806 VEHICLE HEIGHT SENSOR LOCK-
ING MALFUNCTION .........................................
14
Description ........................................................... ....14
DTC Logic ................................................................14
Diagnosis Procedure ...............................................14
C1807 SENSOR 5V MALFUNCTION ...............15
Description ...............................................................15
DTC Logic ................................................................15
Diagnosis Procedure ..............................................15
C1808 INTEGRAL TIME MALFUNCTION
SUPPLYING AIR ...............................................
16
Description ...............................................................16
DTC Logic ................................................................16
Diagnosis Procedure ..............................................16
POWER SUPPLY AND GROUND CIRCUIT ....17
SUSPENSION CONTROL UNIT ................................17
SUSPENSION CONTROL UNI T : Diagnosis Pro-
cedure .................................................................. ....
17
SUSPENSION AIR COMPRESSOR ..........................17
SUSPENSION AIR COMPRESSOR : Diagnosis
Procedure ............................................................ ....
17
HEIGHT SENSOR .................................................. ....18
HEIGHT SENSOR : Diagnosis Procedure ..............18
COMPRESSOR MOTOR RELAY .....................20
Description ...............................................................20
Component Function Check ....................................20
Diagnosis Procedure ...............................................20
HEIGHT SENSOR SIGNAL CIRCUIT ...............22
Description ...............................................................22
Component Function Check ....................................22
Diagnosis Procedure ...............................................22
Revision: March 2010 2008 QX56