INFINITI QX56 2011 Factory Service Manual

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
Revision: 2010 May2011 QX56

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
JSEIA0217ZZ
1. Air valve 2. Air chamber 3. Rubber
A. Stroke
: Vehicle upper
JSEIA0218ZZ
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.
JSEIA0219ZZ
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SCS-54
< 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
JSEIA0220GB
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
Revision: 2010 May2011 QX56

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.
JSEIA0221GB
Revision: 2010 May2011 QX56

SCS-56
< SYSTEM DESCRIPTION >[AIR LEVELIZER CONTROL SYSTEM]
DIAGNOSIS SYSTEM (AIR
LEVELIZER CONTROL MODULE)
DIAGNOSIS SYSTEM (AIR LE VELIZER CONTROL MODULE)
CONSULT-III FunctionINFOID:0000000006256052
CONSULT-III APPLICATION ITEMS
WORK SUPPORT
CAUTION:
Perform the procedure when the vehicle is stopped.
SELF DIAGNOSTIC RESULTS
Refer to SCS-59, "DTC Index".
When “CRNT” is displayed on self-diagnosis result,
 The system is presently malfunctioning.
When “PAST” is displayed on self-diagnosis result, System malfunction in the past is detect ed, but the system is presently normal.
Freeze frame data (FFD)
DATA MONITOR
Diagnostic test mode Function
Work Support This mode enables a technician to adjust some devices faster and more accurately.
Self Diagnostic Results Retrieve DTC from ECU and display diagnostic items.
Data Monitor Monitor the input/output signal of the control unit in real time.
CAN Diagnosis This mode displays a network diagnosis result about CAN by a diagram.
CAN Diagnostic Support
Monitor It monitors the status of CAN communication.
ECU Identification Display the ECU identification number (part number etc.) of the selected system.
Active Test Send the drive signal from CONSULT-III to the actuator. The operation check can be performed.
Item name Description
STANDARD HEIGHT LEVEL Forcibly sets vehicle height to the set standard vehicle height.
ADJUST HEIGHT INI Sets standard vehicle height.
CLEAR HEIGHT INI Erases standard vehicle height.
Item name Description
IGN COUNTER The number of times that ignition switch is turned ON after the DTC is detected is displayed.
 When “0” is displayed: It indicates that the system is presently malfunctioning.
 When except “0” is displayed: It indicates that system malfunction in the past is detected, but the system
is presently normal.
NOTE:
Each time when ignition switch is turned OFF to ON, numerical number increases in 1 → 2 → 3...38 → 39.
When the operation number of times exceeds 39, the number do not increase and “39” is displayed until
self-diagnosis is erased.
Monitored item (Unit) Remarks
IGN VOLT (V) Displays the power supply voltage of air levelizer control module.
VHCL HT INTLZ STA Displays setting status of standard vehicle height.
VHCL HT INIT SLCT Displays setting status of standard vehicle height.
VHCL HEIGHT SEN (V) Displays the signal voltage of vehicle height sensor.
VHCL HT CNVSN VL (mm) Displays the vehicle height recognized by air levelizer control module.
VHCL HGT FIX TIME (hour) Displays period of time that signal from vehicle height sensor does not change.
Revision: 2010 May2011 QX56

DIAGNOSIS SYSTEM (AIR LEVELIZER CONTROL MODULE)
SCS-57
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ACTIVE TEST
CAUTION:
 Perform the procedure when the vehicle is stopped.
 Be careful that battery is not discharged when pe rforming the procedure while engine is stopped.
VHCL HGT INIT VAL (V)  Displays voltage when standard vehicle height is set.
 Value does not change until setting of standard vehicle height is performed again.
COMPRESSOR Displays operation status of air compressor.
EXH SOLENOID Displays operation status of exhaust solenoid.
ENG SPEED SIG Displays operation status of engine.
WARNING LAMP Displays turning ON st atus of CK SUSP indicator lamp.
Monitored item (Unit) Remarks
Item name Description
COMPRESSOR Air compress or can be operated.
EXHAUST SOLENOID Ehaust solenoid of air compressore can be operated.
WARNING LAMP CK SUSP indicator lamp can be turned ON or OFF.
Revision: 2010 May2011 QX56

SCS-58
< ECU DIAGNOSIS INFORMATION >[AIR LEVELIZER CONTROL SYSTEM]
AIR LEVELIZER CONTROL MODULE
ECU DIAGNOSIS INFORMATION
AIR LEVELIZER CONTROL MODULE
Reference ValueINFOID:0000000006256053
VALUES ON DIAGNOSIS TOOL
TERMINAL LAYOUT
PHYSICAL VALUES
Item name Condition Value/Status (Approx.)
IGN VOLT Ignition switch ON 10 – 16 V
VHCL HT INTLZ STA Completion of the standard vehicle height setting CMPLT
Other than the above INCMP
VHCL HT INIT SLCT Completion of the standard vehicle height setting 1
Other than the above 0
VHCL HEIGHT SEN Lift up the vehicle 2.8 – 3.8 V
VHCL HT CNVSN VL Lift down the vehicle −15 – 15 mm
VHCL HGT FIX TIME Lift up the vehicle 0 h
VHCL HGT INIT VAL Completion of the standard vehicle height setting 2.800 – 3.800 V
Other than the above 0 V
COMPRESSOR When the air compressor is operating On
Other than the above Off
EXH SOLENOID When exhaust solenoid is operating On
Other than the above Off
ENG SPEED SIG Engine running RUN
Other than the above STOP
WARNING LAMP When CK SUSP indicator lamp is ON On
Other than the above Off
JSDIA0057ZZ
Terminal
(Wire color) Description
ConditionReference value
(Approx.)
+ − Signal name Input/
Output
2
(B) Ground GND — Always Less than 1
Ω
3
(V) Ground Air compressor relay Output IGN ON Air compressor: ON 9 – 16 V
Air compressor: OFF Less than 2 V
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(L/W) Ground Vehicle height sensor
(GND) — Always Less than 1
Ω
Revision: 2010 May2011 QX56

AIR LEVELIZER CONTROL MODULESCS-59
< ECU DIAGNOSIS INFORMATION > [AIR LEVELIZER CONTROL SYSTEM]
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Fail-safeINFOID:0000000006256054
If malfunction is detected, control stops.
The system may enter fail-safe mode under certain condi tions (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.
DTC Inspection Priority ChartINFOID:0000000006256055
If some DTCs are displayed at the same time, per form inspections one by one based on the following priority
chart.
DTC IndexINFOID:0000000006256056
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(W) Ground Vehicle height sensor
(SIGNAL) InputIGN ON 0.2 – 4.6 V
IGN OFF 0 V
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(P) 16
(L) CAN-L
Input/
Output — 54 – 69
Ω
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(P/L) Ground Air levelizer co
ntrol module
power supply InputIGN ON 10 – 16 V
IGN OFF 0 V
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(V/W) Ground Exhaust solenoid Output IGN ON Exhaust solenoid: ON 9 – 16 V
Exhaust solenoid: OFF Less than 2 V
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(R) Ground Vehicle height sensor
(Power supply)
OutputIGN ON 4.5 – 5.5 V
IGN OFF 0 V
16
(L) 7
(P) CAN-H Input/
Output — 54 – 69
Ω
Te r m i n a l
(Wire color) Description
ConditionReference value
(Approx.)
+ − Signal name Input/
Output
Priority Detected items (DTC)
1  U1000 CAN COMM CIRCUIT
 U1010 CONTROL UNIT (CAN)
2  C1801 VHCL HEIGHT SENSOR
 C1802 AIR SUS COMPRS RELAY
 C1803 AIR SUS EXH SOL
 C1806 VHCL HEIGHT SEN FIX
 C1807 VHCL HEIGHT SEN VOLT
3  C1804 VHCL HEIGHT ADJ UP
 C1805 VHCL HEIGHT ADJ DOWN
 C1808 AIR SUS COMPRS FNCTN
DTC CONSULT-III display Reference page
C1801 VHCL HEIGHT SENSOR SCS-69
C1802 AIR SUS COMPRS RELAYSCS-72
C1803 AIR SUS EXH SOLSCS-74
C1804 VHCL HEIGHT ADJ UPSCS-77
C1805 VHCL HEIGHT ADJ DOWNSCS-80
C1806 VHCL HEIGHT SEN FIXSCS-81
C1807 VHCL HEIGHT SEN VOLTSCS-82
C1808 AIR SUS COMPRS FNCTNSCS-84
Revision: 2010 May2011 QX56

SCS-60
< ECU DIAGNOSIS INFORMATION >[AIR LEVELIZER CONTROL SYSTEM]
AIR LEVELIZER CONTROL MODULE
U1000 CAN COMM CIRCUIT
SCS-87
U1010 CONTROL UNIT (CAN)SCS-88
Revision: 2010 May2011 QX56