Infiniti QX56 (Z62). Manual - part 1104

STRUCTURE AND OPERATION

SCS-53

< SYSTEM DESCRIPTION >

[AIR LEVELIZER CONTROL SYSTEM]

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Vehicle Height Sensor

INFOID: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

SCS-54

< SYSTEM DESCRIPTION >

[AIR LEVELIZER CONTROL SYSTEM]

SYSTEM

SYSTEM

System Diagram

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System Description

INFOID:0000000006256050

• Based on the signal from the vehicle height sensor, the 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 indicator lamp signal

ABS actuator and electric unit (con-
trol unit)

Transmits the following signal via CAN communication line to air levelizer control module.
• Vehicle speed signal

SYSTEM

SCS-55

< SYSTEM DESCRIPTION >

[AIR LEVELIZER CONTROL SYSTEM]

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Vehicle height raises [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 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 status is +1 mm (+0.04 in) of standard vehicle height.

Fail-safe

INFOID: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 returns to normal by starting engine after unloading load.

JSEIA0221GB

SCS-56

< SYSTEM DESCRIPTION >

[AIR LEVELIZER CONTROL SYSTEM]

DIAGNOSIS SYSTEM (AIR LEVELIZER CONTROL MODULE)

DIAGNOSIS SYSTEM (AIR LEVELIZER CONTROL MODULE)

CONSULT-III Function

INFOID: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 detected, 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.