2006 INFINITI QX56 air suspension

RSU-2Revision: November 20092006 QX56
STABILIZER BAR ..................................................
... 42
Removal and Installation ..................................... ... 42
REMOVAL ........................................................ ... 42
INSPECTION AFTER REMOVAL ..................... ... 42
INSTALLATION ................................................. ... 42
REAR LOAD LEVELING AIR SUSPENSION COM-
PRESSOR ASSEMBLY ............................................ 43 Removal and Installation ..................................... ... 43
REMOVAL ........................................................ ... 43
INSTALLATION ................................................. ... 44HEIGHT SENSOR ..................................................
... 45
Removal and Installation ...................................... ... 45
REMOVAL ......................................................... ... 45
INSTALLATION ................................................. ... 46
CONTROL UNIT ..................................................... ... 47
Removal and Installation ...................................... ... 47
REMOVAL ......................................................... ... 47
INSTALLATION ................................................. ... 47
Initialization Procedure ......................................... ... 47
SERVICE DATA AND SPECIFICATIONS (SDS) ... ... 48
Wheel Alignment .................................................. ... 48
Ball Joint .............................................................. ... 48
Wheelarch Height (Unladen*
1 ) ............................ ... 49

PRECAUTIONSRSU-3
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EES001GX
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER ”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WARNING:

To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Precautions for Rear SuspensionEES001GY

When installing the rubber bushings, the final tightening must be done under unladen condition and with
the tires on level ground. Oil will shorten the life of the rubber bushings, so wipe off any spilled oil immedi-
ately.

Unladen condition means the fuel tank, engine coolant and lubricants are at the full specification. The
spare tire, jack, hand tools, and mats are in their designated positions.

After installing suspension components, check the wheel alignment.

Caulking nuts are not reusable. Always use new caulking nuts for installation. New caulking nuts are pre-
oiled, do not apply any additional lubrication.

NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTINGRSU-5
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTINGPFP:00003
NVH Troubleshooting ChartEES001H1
Use chart below to help you find the cause of the symptom. If necessary, repair or replace these parts.
×: ApplicableReference page
RSU-26RSU-35
—
—
—
RSU-26
RSU-28RSU-42
PR-3, "
NVH Troubleshooting Chart
"
RFD-7, "
NVH Troubleshooting Chart
"
FAX-4, "
NVH Troubleshooting Chart
"
FSU-4, "
NVH Troubleshooting Chart
"
WT-4, "
NVH Troubleshooting Chart
"
WT-4, "
NVH Troubleshooting Chart
"
RAX-4, "
NVH Troubleshooting Chart
"
PS-5, "
NVH Troubleshooting Chart
"
BR-5, "
NVH Troubleshooting Chart
"
Possible cause and SUSPECTED PARTS
Improper installation, looseness
Shock absorber deformation, damage or deflection
Bushing or mounting deterioration
Parts interference
Spring fatigue
Suspension looseness
Incorrect wheel alignment
Stabilizer bar fatigue
PROPELLER SHAFT
DIFFERENTIAL
FRONT AXLE
FRONT SUSPENSION
TIRES
ROAD WHEEL
DRIVE SHAFT
BRAKES
STEERING
Symptom Noise
×××××× ××× ××××××
Shake ×××× × × × ××××××
Vibration ××××× × × ×× × ×
Shimmy ×××× × × ××× ××
Shudder ××× × ××× ××
Poor quality ride or handling ××××× ×× × ×××

TROUBLE DIAGNOSISRSU-7
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
TROUBLE DIAGNOSISPFP:00000
How to Perform Trouble Diagnoses for Quick and Accurate RepairEES001H3
INTRODUCTION
The rear load leveling air suspension system uses an electronic con-
trol unit to control major functions. The control unit accepts input sig-
nals from the height sensor and controls compressor and exhaust
valve operation.
It is much more difficult to diagnose a rear load leveling air suspen-
sion system problem that occurs intermittently rather than continu-
ously. Most intermittent problems are caused by poor electrical
connections or faulty wiring. In this case, careful checking of suspi-
cious circuits may help prevent the replacement of good parts.
Before undertaking actual checks, take just a few minutes to talk with
a customer who approaches with an air suspension system com-
plaint. The customer is a very good source of information on such
problems, especially intermittent ones. Through discussion with the
customer, find out what symptoms are present and under what con-
ditions they occur.
Start your diagnosis by looking for basic mechanical problems first.
This is one of the best ways to troubleshoot concerns on an air sus-
pension system equipped vehicle. Also check related Service Bulle-
tins for information.
CLARIFY CONCERN

A customer's description of a vehicle concern may vary depend-
ing on the individual. It is important to clarify the customer's con-
cern.

Ask the customer about what symptoms are present under what
conditions. Use this information to reproduce the symptom.
SEF233G
SEF234G
SBR339B

RSU-12
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Basic InspectionEES001H6
AIR HOSES
1. Check for pinched or damaged air hoses between the suspension air reservoir and each load leveling rear
air suspension shock absorber. Reposition, repair or replace hoses as necessary.
2. Check the air hose connections at the suspension air reservoir and at the shock absorbers for leaks. If connections are leaking, repair or replace hoses as necessary.
POWER SYSTEM TERMINAL LOOSENESS AND BATTERY INSPECTION
Make sure the battery positive cable, negative cable and ground connection are not loose. In addition, make
sure the battery is sufficiently charged.
CK SUSP INDICATOR LAMP INSPECTION
1. Make sure the CK SUSP indicator lamp turns on for approximately 2 seconds when the ignition switch is
turned ON. If it does not, check the combination meter. Refer to DI-5, "
COMBINATION METERS" .
2. Make sure the lamp turns off approximately 2 seconds after the ignition switch is turned ON. If the lamp does not turn off, conduct self-diagnosis of the suspension control unit.
3. After conducting the self-diagnosis, be sure to erase the error memory. Refer to RSU-13, "
CONSULT-II
Function (AIR LEVELIZER)" .
CK SUSP Indicator Lamp TimingEES001H7
X: ON
—: OFF
Control Unit Input/Output Signal StandardEES001H8
ConditionCK SUSP
indicator lamp Remarks
Ignition switch OFF ––
Ignition switch ON X Turns off after approximately 2 seconds.
Te r m i n a l
No. Wire color
Item ConditionVoltage (V)
(Approx.)
1 V Compressor relay output
Ignition switch ON or STARTBattery voltage
3 W Height sensor signal input 0.2V - 4.8V
5 R Reference voltage 5V
6 G/R Ignition power
Battery voltage
7W /LB atte ry p ow er —
8 G/W Diagnostic K-line ——
9 SB Exhaust valve output Ignition switch ON or STARTBattery voltage
10 BR Warning lamp output ——
14 L Height sensor ground ——
15 BR/W Generator L signal input Engine running—
16 B Suspension control unit ground —0V

TROUBLE DIAGNOSISRSU-13
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
CONSULT-II Function (AIR LEVELIZER)EES001H9
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II OPERATION
1. Turn ignition switch OFF.
2. Connect CONSULT-II and CONSULT-II CONVERTER to the
data link connector.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II
CONVERTER, malfunctions might be detected in self-diag-
nosis depending on control unit which carries out CAN
communication.
3. Turn ignition switch ON.
4. Touch "START (NISSAN BASED VHCL)".
5. Touch "AIR LEVELIZER" in the "SELECT SYSTEM" screen. If "AIR LEVELIZER" is not indicated, go to GI-40, "
CONSULT-II
Data Link Connector (DLC) Circuit" .
AIR LEVELIZER
diagnostic mode Description
WORK SUPPORT Supports inspections and adjustments. Commands are transmitted to the BCM for setting the status
suitable for required operation, input/output signals are received from the BCM and received data is
displayed.
SELF-DIAG RESULTS Displays suspension control unit self-diagnosis results. DATA MONITOR Displays suspension control unit input/output data in real time.ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
ECU PART NUMBER Suspension control unit part number can be read.
BBIA0369E
BCIA0029E
BCIA0030E

TROUBLE DIAGNOSISRSU-15
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
WORK SUPPORT
Operation Procedure
1. After turning OFF the ignition switch, connect CONSULT-II and the CONSULT-II CONVERTER to the data
link connector.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
2. Touch "START (NISSAN BASED VHCL)", "AIR LEVELIZER", "WORK SUPPORT" in order on the CON- SULT-II screen.
If "AIR LEVELIZER" is not indicated, go to GI-40, "
CONSULT-II Data Link Connector (DLC) Circuit" .
CAUTION:
When "START (NISSAN BASED VHCL)" is touched immediately after starting the engine or turning
on the ignition switch, "AIR LEVELIZER" might not be displayed in the "SELECT SYSTEM" screen.
In this case, repeat the operation from step 2.
3. Select "STANDARD HEIGHT LEVEL", "ADJUST HEIGHT INI" or "CLEAR HEIGHT INI" on the "SELECT WORK ITEM" screen.
NOTE:
Read and perform screen instructions if "STANDARD HEIGHT LEVEL" or "ADJUST HEIGHT INI" is
selected.
4. Touch "START" to begin the desired work support.
Display Item List
Vehicle height adjusting trouble
(compressor)
[C1804] Continuous compressor relay ON time is more than 120 sec-
onds. Refer to
RSU-21, "Compres-
sor Motor, Compressor
Motor Relay and Circuit
Inspection" .
Vehicle height adjusting trouble
(exhaust solenoid)
[C1805] Continuous exhaust solenoid ON time is more than 120 seconds. Refer to
RSU-19, "
Exhaust
Valve Solenoid System
Inspection" .
Vehicle height sensor locking trou-
ble
[C1806] Output sensor voltage variation ±
0.02V is more than 100 hour
when vehicle height range is normal. Refer to
RSU-18, "
Height
Sensor System Inspection" .
Sensor 5V trouble
[C1807] Sensor reference voltage is less than 0.8V or more than 6V for
20 seconds. Refer to
RSU-18, "
Height
Sensor System Inspection" .
Integral time trouble by supplying
air
[C1808] Integral discontinuous time on the compressor is more than 180
seconds. Refer to
RSU-21, "
Compres-
sor Motor, Compressor
Motor Relay and Circuit
Inspection" .
Self-diagnostic item
Malfunction detecting condition Check system
ItemDescription Condition
STANDARD HEIGHT LEVEL Resets the vehicle height to the initialization flag
setting stored in the suspension control unit. Vehicle unladen
RSU-49, "
Wheelarch Height
(Unladen*1 )" , set in a horizontal position and
not moving.
NOTE:
Do not take your eyes off the vehicle while
CONSULT-II is processing.
ADJUST HEIGHT INI Sets the height initialization flag in the suspension
control unit when the control unit has been replaced
or when the initialization flag has been cleared
using the "CLEAR HEIGHT INI" procedure. Vehicle unladen
RSU-49, "
Wheelarch Height
(Unladen*1 )" . Move vehicle forward and
backward approx. 5 m (16.4 ft) and rock vehi-
cle from side to side.
NOTE:
Do not move vehicle while CONSULT-II is pro-
cessing.
CLEAR HEIGHT INI Clears the initialization flag in the suspension con-
trol unit. Vehicle unladen
RSU-49, "
Wheelarch Height
(Unladen*1 )" .

TROUBLE DIAGNOSISRSU-17
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-II. Allowing the
compressor to run for an extended period of time may cause damage to air suspension system com-
ponents due to excessive pressure in the air suspension system.
NOTE:

"TEST IS STOPPED" is displayed approximately 10 seconds after operation starts for all active test items
except "COMPRESSOR".

After "TEST IS STOPPED" is displayed, to perform test again, repeat Step 6.
EXHAUST SOLENOIDOFF/ON
WARNING LAMP OFF/ON
Test Item
Description