2011 INFINITI QX56 ABS

SCS-2
ACCUMULATOR ......................................................34
ACCUMULATOR : Exploded View .........................35
ACCUMULATOR : Removal and Installation ..........35
ACCUMULATOR : Inspection ................................38
ACCUMULATOR : Disposal ...................................38
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE ...38
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Exploded View ......................................................
39
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Removal and Installation ......................................
39
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Inspection .............................................................
43
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Disposal ................................................................
43
REAR TUBE ASSEMBLY ...................................... ...43
REAR TUBE ASSEMBLY : Exploded View ............44
REAR TUBE ASSEMBLY : Removal and Installa-
tion ....................................................................... ...
44
REAR TUBE ASSEMBLY : Inspection ...................46
AIR LEVELIZER CONTROL SYSTEM
PRECAUTION ....... ....................... ...............
47
PRECAUTIONS .............................................. ...47
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" .............................................................. ...
47
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect ..................................
47
Precaution for Procedure without Cowl Top Cover ...48
Precaution for Air Levelizer Control System ...........48
SYSTEM DESCRIPTION ............................49
DESCRIPTION ................................................ ...49
Description ........................................................... ...49
COMPONENT PARTS .......................................50
Component Parts Location .................................. ...50
Component Description ..........................................50
Air Levelizer Control Module ..................................51
Vehicle Height Sensor ............................................51
Air Compressor .......................................................51
Air Compressor Relay ............................................51
CK SUSP Indicator Lamp .......................................51
STRUCTURE AND OPERATION ......................52
Rear Shock Absorber .......................................... ...52
Vehicle Height Sensor ............................................53
SYSTEM .......................................................... ...54
System Diagram .................................................. ...54
System Description .................................................54
Fail-safe ..................................................................55
DIAGNOSIS SYSTEM (AIR LEVELIZER
CONTROL MODULE) ........................................
56
CONSULT-III Function ........................................ ...56
ECU DIAGNOSIS INFORMATION .............58
AIR LEVELIZER CONTROL MODULE .......... ...58
Reference Value .................................................. ...58
Fail-safe ..................................................................59
DTC Inspection Priority Chart .................................59
DTC Index ...............................................................59
WIRING DIAGRAM ....................................61
AIR LEVELIZER CONTROL SYSTEM ........... ...61
Wiring Diagram .................................................... ...61
BASIC INSPECTION ..................................65
DIAGNOSIS AND REPAIR WORKFLOW ...... ...65
Work Flow ............................................................ ...65
Diagnostic Work Sheet ...........................................66
STANDARD VEHICLE HEIGHT SETTING .......67
Description ........................................................... ...67
Work Procedure ......................................................67
DTC/CIRCUIT DIAGNOSIS ........................69
C1801 VHCL HEIGHT SENSOR .................... ...69
DTC Logic ............................................................ ...69
Diagnosis Procedure ..............................................69
Component Inspection ............................................70
C1802 AIR SUS COMPRS RELAY ...................72
DTC Logic ............................................................ ...72
Diagnosis Procedure ..............................................72
C1803 AIR SUSPENSION EXH SOL ................74
DTC Logic ............................................................ ...74
Diagnosis Procedure ..............................................74
Component Inspection ............................................75
C1804 VHCL HEIGHT ADJ UP .........................77
DTC Logic ............................................................ ...77
Diagnosis Procedure ..............................................77
Component Inspection (Air Compressor Relay) .....79
Component Inspection (Air Compressor) ............. ...79
C1805 VHCL HEIGHT ADJ DOWN ...................80
DTC Logic ............................................................ ...80
Diagnosis Procedure ..............................................80
C1806 VHCL HEIGHT SEN FIX ........................81
DTC Logic ............................................................ ...81
Diagnosis Procedure ...............................................81
C1807 VHCL HEIGHT SEN VOLT ....................82
DTC Logic ............................................................ ...82
Diagnosis Procedure ..............................................82
C1808 AIR SUS COMPRS FNCTN ...................84
DTC Logic ............................................................ ...84
Diagnosis Procedure ..............................................84
U1000 CAN COMM CIRCUIT ............................87
Revision: 2010 May2011 QX56

SCS-6
< PREPARATION >[HBMC]
PREPARATION
PREPARATION
PREPARATION
Special Service ToolsINFOID:0000000006255997
The actual shapes of Kent-Moore tool
s may differ from those of special service tools illustrated here.
Commercial Service ToolsINFOID:0000000006414888
Tool number
(Kent-Moore No.)
Tool name Description
KV40107700
(—)
Suspension oil pump  Air bleeding
 System diagnosis
KV40108000
(—)
Oil pressure gauge System pressure check
KV40108400
(—)
Leak check plug Shock absorber leakage check
JSEIA0183ZZ
JSEIA0184ZZ
JSEIA0185ZZ
Tool name
Description
Power tool Loosening bolts and nuts
PBIC0190E
Revision: 2010 May2011 QX56

DESCRIPTIONSCS-7
< SYSTEM DESCRIPTION > [HBMC]
C
D
F
G H
I
J
K L
M A
B
SCS
N
O P
SYSTEM DESCRIPTION
DESCRIPTION
DescriptionINFOID:0000000006255998
 Hydraulic body-motion control s ystem is adopted, which makes shock absorber stroke appropriately by
hydraulic pressure according to driving scenes.
 The adoption of this system allows the reduction in a ro ll angle (i.e. vehicle body tilt angle at cornering) to
improve steering stability and ride quality during travel on level roads. Furthermore, the use of this system
improves the running performance on rough roads by shock absorption and quality tire adhesion through
maximized stroke.
Revision: 2010 May2011 QX56

SCS-8
< SYSTEM DESCRIPTION >[HBMC]
COMPONENT PARTS
COMPONENT PARTS
Component Parts LocationINFOID:0000000006255999
Component DescriptionINFOID:0000000006256000
1. Middle tube assembly RH 2. Accumulator assembly RH 3. Front tube assembly A
4. Front tube assembly B 5. Accumulator assembly LH 6. PPMU pipe A
7. PPMU assembly 8. Middle tube assembly LH 9. PPMU pipe B
10. Rear tube assembly A 11. Rear tube assembly B
:Vehicle front
JSEIA0228ZZ
Component parts Reference
Shock absorber SCS-9, "
Shock Absorber"
AccumulatorSCS-11, "Accumulator"
PPMUSCS-10, "PPMU"
PPMU pipe A
SCS-11, "PPMU Pipe"PPMU pipe B
Revision: 2010 May2011 QX56

STRUCTURE AND OPERATIONSCS-9
< SYSTEM DESCRIPTION > [HBMC]
C
D
F
G H
I
J
K L
M A
B
SCS
N
O P
STRUCTURE AND OPERATION
Hydraulic Body-Moti on Control SystemINFOID:0000000006256001
Shock AbsorberINFOID:0000000006256002
The use of accumulator-generated pressure responsive to driving conditions or pressure generated by oil flow
to the upper/lower chamber improves the steering stabili ty at curving, in addition to the running performance
and a ride quality during off-road travel.
FRONT SIDE
Oil enters from oil inlet outlet hole (A) and flows into lower chamber (3) via outside oil path of cylinder inside.
Oil enters from oil inlet outlet hole (B) and flows into upper chamber (1). With the pressure difference between
oil flowed into the upper chamber and lower chamber, the piston (2) moves up and down and conveys a force
generated through this motion to the tires.
1. Middle tube assembly RH 2. Accumulator assembly RH 3. Front tube assembly A
4. Front tube assembly B 5. Accumulator assembly LH 6. PPMU pipe A
7. PPMU assembly 8. Middle tube assembly LH 9. PPMU pipe B
10. Rear tube assembly A 11. Rear tube assembly B
:Vehicle front
JSEIA0228ZZ
Revision: 2010 May2011 QX56

STRUCTURE AND OPERATIONSCS-11
< SYSTEM DESCRIPTION > [HBMC]
C
D
F
G H
I
J
K L
M A
B
SCS
N
O P
When system pressure decreases, influent oil is dist ributed to both pipes by gas spring reaction force of
nitrogen gas via PPMU pipe A and PPMU pipe B to control sudden decrease in system pressure.
AccumulatorINFOID:0000000006256004
Influent oil from both front and rear shock absorbers on the outer ring flows simultaneously into the oil cham-
ber during cornering, and gas spring reaction force of ni trogen gas increases pressure, according to the influ-
ent oil level. As for inner ring side, the gas spring conv eys oil from the oil chamber to both front and rear shock
absorbers and decreases pressure, according to the oil level.
PPMU PipeINFOID:0000000006256005
PPMU and right and left tubes are connected. When oil in creases according to increase of system pressure,
increased amount of oil is sent to PPMU. When system pressure decreases, oil discharged from PPMU is sent
to right and left tubes.
1. Oil chamber 2. Bellows 3. Gas chamber
JSEIA0175ZZ
1. Oil chamber 2. Gas chamber 3. Bellows
JSEIA0176ZZ
Revision: 2010 May2011 QX56

SCS-12
< SYSTEM DESCRIPTION >[HBMC]
SYSTEM
SYSTEM
System DiagramINFOID:0000000006256006
System DescriptionINFOID:0000000006256007
 Drivability during cornering and driving on rough road
is improved by mechanically generating oil pressure
by connecting 4 units of shock absor bers to front, rear, right, and left by piping lines of 2 systems.
 Oil filling and system diagnosis can be performed using PPMU.
OPERATING PRINCIPLE
During cornering (Front and rear wheels in the outer side of corner: compressing)
When shock absorber in the outer side of corner is compressed during cornering, oil moves along piping path
and overflowing oil from piping path flows in accumulato r in the outer side of corner. Then, pressure increases
by action of gas spring of nitrogen gas acco rding to amount of oil that flows in.
Pressure in the inner side of corner decreases, since oil is discharged from accumulator by stroke (extending
direction) of shock absorber.
The pressure difference generates stabilizer-like action to maintain balance in vehicle posture for a steady
driving at cornering.
JSEIA0179GB
Revision: 2010 May2011 QX56

SYSTEMSCS-13
< SYSTEM DESCRIPTION > [HBMC]
C
D
F
G H
I
J
K L
M A
B
SCS
N
O P
During rough road driving (Front wheel LH: compressing, front wheel RH: extending, rear wheel LH: extending, rear
wheel RH: compressing)
Discharged oil from each shock absorber moves along piping
path, but oil does not overflow from piping path,
since oil moves in between each shock absorber. Oil does not flow in accumulator and system pressure does
not increase.
Since the oil from the contracted shock absorber flow s into the shock absorber upper chamber, stabilizer-like
action is not generated. This improves the adhes ion level and the running performance on rough roads.
JSEIA0177GB
Revision: 2010 May2011 QX56