height INFINITI QX56 2011 Factory Service Manual

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Description ..........................................................
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87
DTC Logic ...............................................................87
Diagnosis Procedure ...............................................87
U1010 CONTROL UNIT (CAN) ..........................88
Description .......................................................... ....88
DTC Logic ...............................................................88
Diagnosis Procedure ...............................................88
POWER SUPPLY AND GROUND CIRCUIT ......89
Diagnosis Procedure .......................................... ....89
CK SUSP INDICATOR LAMP CIRCUIT ............90
Description .......................................................... ....90
Component Function Check ....................................90
Diagnosis Procedure ...............................................90
SYMPTOM DIAGNOSIS ..............................91
VEHICLE HEIGHT CANNOT BE RAISED ..... ....91
Description .......................................................... ....91
Diagnosis Procedure ...............................................91
VEHICLE HEIGHT CANNOT BE LOWERED ....92
Description ..............................................................92
Diagnosis Procedure ........................................... ....92
CK SUSP INDICATOR LAMP DOES NOT
TURN OFF ........................................ .................
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Description ........................................................... ....93
Diagnosis Procedure ...............................................93
REMOVAL AND INSTALLATION ...............94
AIR LEVELIZER CONTROL MODULE ............94
Exploded View ..................................................... ....94
Removal and Installation .........................................94
Adjustment ...............................................................94
AIR COMPRESSOR/AIR TUBE ........................95
Exploded View .........................................................95
Removal and Installation .........................................95
Inspection ................................................................97
VEHICLE HEIGHT SENSOR ............................98
Exploded View .........................................................98
Removal and Installation .........................................98
Adjustment ...............................................................99
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DIFFERENCE IN APPEARANCESCS-29
< SYMPTOM DIAGNOSIS > [HBMC]
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SYMPTOM DIAGNOSIS
DIFFERENCE IN APPEARANCE
DescriptionINFOID:0000000006256016
While the vehicle is stopped, the difference of vehicle height of right side and left side (between wheel center
and wheel arch) is 25 mm (0.98 in) or more.
Inspection ProcedureINFOID:0000000006256017
1.CHECK APPEARANCE
1. Visually check that the exterior parts (e.g. suspension spring) have no malfunctions.
2. Visually check tube and pipe for crush or oil leakage.
Is the check result normal?
YES >> GO TO 2.
NO >> Repair or replace damaged parts.
2.CHECK CLOGGING OF ORIFICE IN PPMU
1. Install an oil pressure gauge (SST: KV40108000) (A) to oil injec- tion jack.
CAUTION:
 Clean surrounding areas of oi l injection jack using steam
before starting oper ation, since there may be mud on it.
 Clean oil pressure gauge (special service tool:
KV40108000) jack with steam before use.
 Jack must be securely inserted until a click sound can be heard.
 Pressure reducing valve (B) of the oil pressure gauge
must be closed.
2. Loosen needle valves A and C of PPMU by approximately 2 rotations for check changes in vehicle height.
CAUTION:
Never loosen the needle valve more than required.
3. Tighten needle valve A and C of PPMU to the specified torque after the inspection.
Does the vehicle height change 10 mm (0.39 in) or more?
YES >> For detailed inspection of clogging of orifice in PPMU, refer to SCS-27, "
Work Procedure".
NO >> INSPECTION END
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Tightening torque : 8.3 N· m (0.85 kg-m, 73 in-lb)
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SCS-48
< PRECAUTION >[AIR LEVELIZER CONTROL SYSTEM]
PRECAUTIONS
5. When the repair work is completed, re-connect bot
h battery cables. With the brake pedal released, turn
the push-button ignition switch from ACC position to ON position, then to LOCK position. (The steering
wheel will lock when the push-button igniti on switch is turned to LOCK position.)
6. Perform self-diagnosis check of all control units using CONSULT-III.
Precaution for Procedure without Cowl Top CoverINFOID:0000000006256139
When performing the procedure after removing cowl top cover, cover
the lower end of windshield with urethane, etc.
Precaution for Air Levelizer Control SystemINFOID:0000000006256038
 Never allow water and dust to enter the inside of air compressor.
 Never disassemble the vehicle height sensor.
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Revision: 2010 May2011 QX56

DESCRIPTIONSCS-49
< SYSTEM DESCRIPTION > [AIR LEVELIZER CONTROL SYSTEM]
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SYSTEM DESCRIPTION
DESCRIPTION
DescriptionINFOID:0000000006256039
 Corrects sinkage of vehicle rear that occurs in laden or towing conditions.
 Maintains vehicle height at a constant level and improv es riding comfort by charging or discharging air in air
chamber of rear shock absorber, according to signal from vehicle height sensor installed to rear suspension.
Revision: 2010 May2011 QX56

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< SYSTEM DESCRIPTION >[AIR LEVELIZER CONTROL SYSTEM]
COMPONENT PARTS
COMPONENT PARTS
Component Parts LocationINFOID:0000000006256040
Component DescriptionINFOID:0000000006256041
1. Combination meter
Refer to MWI-6, "
METER SYSTEM
: Component Parts Location".2. CK SUSP indicator lamp 3. Air levelizer control module
4. Air compressor relay 5. Air chamber 6. Air compressor
7. Vehicle height sensor
A. Inside of luggage side finisher low- er (LH) B. Engine room (RH) C. Rear shock absorber
D. Vehicle rear (LH)
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Component parts Reference
Air levelizer control module SCS-51, "
Air Levelizer Control Module"
Vehicle height sensorSCS-51, "Vehicle Height Sensor"
Air compressor
SCS-51, "Air Compressor"Exhaust solenoid
Revision: 2010 May2011 QX56

COMPONENT PARTSSCS-51
< SYSTEM DESCRIPTION > [AIR LEVELIZER CONTROL SYSTEM]
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Air Levelizer Control ModuleINFOID:0000000006256042
 Operates ON/OFF of air compressor (exhaust solenoid) , according to signal from vehicle height sensor.
 Transmits CK SUSP indicator lamp signal to the combination meter via CAN communication, when setting of standard vehicle height is incomplete.
 If malfunction is detected, the syste m enters fail-safe mode. Refer to SCS-59, "
Fail-safe".
Vehicle Height SensorINFOID:0000000006256043
Measures vehicle height of vehicle rear and transmits th is information to air levelizer control module according
to electric signal.
Air CompressorINFOID:0000000006256044
Operates according to signal from air levelizer control module via air compressor relay, and charges air in air
chamber of rear shock absorber.
EXHAUST SOLENOID
Operates according to signal from air levelizer control module, and discharges air in air chamber of rear shock
absorber.
Air Compressor RelayINFOID:0000000006256045
Turns ON according to signal from air levelizer control module, and operates air compressor.
CK SUSP Indicator LampINFOID:0000000006256046
 Turns ON for 2 seconds when ignition switch is turned ON, for the purpose of bulb check.
 Turns ON when setting of standard vehicle height is incomplete.
NOTE:
Does not turn ON when the system is malfunctioning.
Air compressor relay SCS-51, "Air Compressor Relay"
CK SUSP indicator lampSCS-51, "CK SUSP Indicator Lamp"
Component parts Reference
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SCS-52
< SYSTEM DESCRIPTION >[AIR LEVELIZER CONTROL SYSTEM]
STRUCTURE AND OPERATION
STRUCTURE AND OPERATION
Rear Shock AbsorberINFOID:0000000006256047
 Discharges air in air chamber (2) from air valve (1)
when vehicle height of vehicle rear is higher than stan-
dard vehicle height, has shock absorber stroke in compressed direction, lowers vehicle height, and returns it
to standard vehicle height.
 Also charges air in air chamber from air valve when height of vehicle rear is lower than standard vehicle
height, has shock absorber stroke in extending directi on, raises vehicle height, and returns it to standard
vehicle height.
 Charged air, because of rubber (3) that is hard and loca ted on side surface, does not expand in lateral direc-
tion, but expands in vertical direction, and enables shock absorber to extend or retract.
Without Hydraulic Body-Motion Control System
With Hydraulic Body-M otion Control System
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1. Air valve 2. Air chamber 3. Rubber
A. Stroke
: Vehicle upper
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1. Air valve 2. Air chamber 3. Rubber
A. Stroke
: Vehicle upper
Revision: 2010 May2011 QX56

STRUCTURE AND OPERATIONSCS-53
< SYSTEM DESCRIPTION > [AIR LEVELIZER CONTROL SYSTEM]
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Vehicle Height SensorINFOID:0000000006256048
Vehicle height sensor is installed between rear suspension member
(1) and rear lower link (2).
Since arm (A) portion and rod (B) portion are ball joint type, distance
between rear suspension member and rear lower link shortens when
vehicle height of vehicle rear lowers because of laden or towing con-
ditions, and arm portion changes to the status that is higher in its left
side as shown in the figure.
This angle change in arm portion is transmitted to the air levelizer
control module according to electric signal.
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< SYSTEM DESCRIPTION >[AIR LEVELIZER CONTROL SYSTEM]
SYSTEM
SYSTEM
System DiagramINFOID:0000000006256049
System DescriptionINFOID:0000000006256050
 Based on the signal from the vehicle height sensor, t
he air levelizer control module operates the air com-
pressor (exhaust solenoid) and controls vehicle height so that it remains at a constant height. This operation
occurs if vehicle height of vehicle rear is judged to be 15 mm (0.59 in) or more or 15 mm (0.59 in) or less
than standard vehicle height, continuously for 30 seconds, when engine is started.
 If malfunction is detected, the system enters fail-safe mode. Refer to SCS-59, "
Fail-safe".
INPUT/OUTPUT SIGNAL
Air levelizer control module transmits and receives following signals between each control unit via CAN com-
munication line.
OPERATING PRINCIPLE
System Time Table
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Component parts Control signal
ECM Transmits the following signal via CAN communication line to air levelizer control module.
 Engine speed signal
Combination meter Receives the following signal via CAN communication line from air levelizer control module.
 CK SUSP indicato
r lamp signal
ABS actuator and elec tric unit (con-
trol unit) Transmits the following signal via CAN communication line to air levelizer control module.
 Vehicle speed signal
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SYSTEMSCS-55
< SYSTEM DESCRIPTION > [AIR LEVELIZER CONTROL SYSTEM]
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Vehicle height raises [When starting engi
ne, if vehicle height of vehicle rear continues for 30 seconds or more in a
status that is 15 mm (0.59 in) or less than standard vehicle height]
1. Vehicle height sensor detects vehicle height status, and transmits this information to air levelizer control
module.
2. Air levelizer control module turns air compressor relay ON and operates air compressor.
3. Air compressor charges air in air chamber of shock absorber.
4. Vehicle height raises, and control is complete when status is −1 mm ( −0.04 in) of standard vehicle height
value.
Vehicle height lowers [When starting engine, if vehicle height of vehicle rear continues for 30 seconds or more in a
status that is 15 mm (0.59 in) or more of standard vehicle height]
1. Vehicle height sensor detects vehicle height status, and transmits this information to air levelizer control
module.
2. Air levelizer control module turns exhaust solenoid of air compressor ON.
3. Air compressor discharges air from air chamber of shock absorber.
4. Vehicle height lowers, and control is complete when st atus is +1 mm (+0.04 in) of standard vehicle height.
Fail-safeINFOID:0000000006256051
If malfunction is detected, control stops.
The system may enter fail-safe mode under certain conditions (for example, over-laden conditions) when elec-
tronic circuit is normal.
In this case, always check that the system re turns to normal by starting engine after unloading load.
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Revision: 2010 May2011 QX56