2008 INFINITI QX56 ignition

SUSPENSION CONTROL UNITSCS-27
< ECU DIAGNOSIS >
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ECU DIAGNOSIS
SUSPENSION CONTROL UNIT
Reference ValueINFOID:0000000001731999
TERMINAL LAYOUT
PHYSICAL VALUES
ALNIA0660GB
Te r m i n a l
(Wire color) Description
ConditionReference value
(Approx.)
+ – Signal nameInput/
Output
1
(V) Ground Compressor relay output Output Ignition
switch
ON Air levelizer ra
ising vehicle
ride height Battery voltage
3
(W) Ground Height sensor input
InputIgnition
switch ON —
0.2V - 4.8V
5
(R) Ground VREF output (height sen-
sor) OutputIgnition
switch ON —5
V
6
(G/R) Ground IGN power supply
InputIgnition
switch
ON or
START —
Battery voltage
7
(W/L) Ground BAT power supply
InputIgnition
switch
OFF —
Battery voltage
8
(G/W) Ground Diagnostic K-line Input/
Output ——
—
9
(SB) Ground Exhaust valve output Output Ignition
switch ON Air levelizer lo
wering vehi-
cle ride height (venting) Battery voltage
10
(BR) Ground Warning lamp output Output Ignition
switch ON Warning lamp ON
0V
Warning lamp OFF Battery voltage
14
(L) Ground Height sensor ground Output Ignition
switch
ON —
Less than 0.2V
15
(BR/W) Ground Generator input
InputIgnition
switch ON Charge light ON
0V
Charge light OFF Battery voltage
16
(B) Ground Suspension control unit
ground InputIgnition
switch ON —
Less than 0.2V
Revision: March 2010 2008 QX56

SCS-36
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM INOPERATIVE
SUSPENSION CONTROL SYSTEM INOPERATIVE
DescriptionINFOID:0000000001732003
The suspension control system does not activate. It does not raise or lower the vehicle in response to ride
height changes.
Diagnosis ProcedureINFOID:0000000001732004
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control unit power and ground pass inspection?
YES >> GO TO 2
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition switch ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.CHECK GENERATOR "L" CIRCUIT SIGNAL
CONSULT-III DATA MONITOR
1. Start the engine.
2. Select "ACG L" of AIR LE VELIZER data monitor item.
3. Check the monitor status.
Is the generator "L" signal operating normally?
YES >> GO TO 4.
NO >> Check generator L circuit. Refer to CHG-14, "
Diagnosis Procedure"
4.SUSPENSION AIR COMPRESSOR POWER AND GROUND INSPECTION
Check the suspension air compressor power and ground supply. Refer to SCS-17, "
SUSPENSION AIR COM-
PRESSOR : Diagnosis Procedure".
Does the suspension air compressor power and ground pass inspection?
YES >> System is operating normally.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
ACG L: OFF with charge light OFF
: ON with charge light ON
Revision: March 2010
2008 QX56

SUSPENSION CONTROL SYSTEM DOES NOT RAISE
SCS-37
< SYMPTOM DIAGNOSIS >
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SUSPENSION CONTROL SYST EM DOES NOT RAISE
DescriptionINFOID:0000000001732005
The suspension control system does not raise the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000001732006
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control uni t power and ground pass inspection?
YES >> GO TO 2
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.SUSPENSION AIR COMPRESSOR POWER AND GROUND INSPECTION
Check the suspension air compressor power and ground supply. Refer to SCS-17, "
SUSPENSION AIR COM-
PRESSOR : Diagnosis Procedure".
Does the suspension air compress or power and ground pass inspection?
YES >> Inspect for a weak compressor, leak or restriction in the system. Repair or replace malfunctioning
part.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
Revision: March 2010 2008 QX56

SCS-38
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
DescriptionINFOID:0000000001732007
The suspension control system does not lower the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000001732008
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control unit power and ground pass inspection?
YES >> GO TO 2
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.EXHAUST VALVE SOLENOID CIRCUIT INSPECTION
Check the exhaust valve solenoid circuit. Refer to SCS-23, "
Component Function Check".
Does the exhaust valve solenoid circuit pass inspection?
YES >> Inspect for a restriction in the system . repair or replace the malfunctioning part.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
Revision: March 2010 2008 QX56

PRECAUTIONSSCS-39
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004900823
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 severi ty 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 w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SR and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inoper ative, 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 performed by
an authorized NISSAN/INFINITI dealer.
• Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintentional act ivation of the system. For removal of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipm ent on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
• When working near the Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
• When using air or electric power tools or hammers, always switch the Ignition OFF, disconnect the battery, and wait at least 3 minutes before performing any service.
Precaution for Rear SuspensionINFOID:0000000001732010
• When installing the rubber bushings, the final tightening must be done under unladen condition and with thetires on level ground. Oil will shorten the life of the rubber bushings, so wipe off any spilled oil immediately.
• 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.
Revision: March 2010 2008 QX56

SE-6
< FUNCTION DIAGNOSIS >
THIRD ROW POWER FOLDING SEAT
FUNCTION DIAGNOSIS
THIRD ROW POWER FOLDING SEAT
System DescriptionINFOID:0000000001735711
The third row power folding seat system is capable of allowing a user to fold up or down either the left or right
third row seat using a set of front or rear mounted switches.
THIRD ROW POWER FOLDIN G SEAT CONTROL UNIT
The third row power folding seat control unit is located in the control
unit/cross beam assembly underneath the LH third row seat. It
receives signals from the third row power folding seat switches, TCM
and the Hall effect switches mounted in the LH and RH seat motors.
The control unit has self-diagnosis capability through chime codes
and may be accessed by turning the ignition switch ON and OFF
three times. The control unit drives the LH and RH seat motors to
fold them up and down.
THIRD ROW POWER FOLDING SEAT SWITCH
The third row power folding seat switches are located in pairs on the
luggage side finisher RH. A switch must be held in order for the seat
to move.
THIRD ROW POWER FOLDING SEAT MOTORS
The third row power folding seat motors are located in the seat
motor/hinge assembly. There are two motors, one for LH and one
for RH seat folding operations. Power and ground are provided to
the motors by the third row power fo lding seat control unit. The con-
trol unit reverses polarity to the motors to raise or lower the seat.
The motors also contain Hall effe ct switches. These switches send
signals back to the control unit which help it determine fully open and
closed positions.
ALJIA0085ZZ
ALJIA0086ZZ
ALJIA0087ZZ
Revision: March 2010 2008 QX56

SE-18
< COMPONENT DIAGNOSIS >
THIRD SEAT
THIRD SEAT
Power Supply and Ground Circuit Check for Third Row Power Folding Seat Control
Unit
INFOID:0000000001735718
1.CHECK FUSES AND FUSIBLE LINK
Check for blown fuses or fusible link.
Are any fuses or fusible links blown?
YES >> Install new fuse. Eliminate cause of malfunction if fuse blows again.
NO >> GO TO 2
2.POWER SUPPLY CIRCUIT CHECK
1. Disconnect third row power folding seat control unit connectors B401 and B402.
2. Check voltage between third row power folding seat control unit harness connectors B401, B402 terminals 1, 8, 13, 14 and
ground.
Are the inspection results normal?
YES >> GO TO 3
NO >> Check harness for open between third row power folding seat control unit and fuse or fusible link.
3.GROUND CIRCUIT CHECK
1. Turn ignition switch OFF.
2. Check continuity between third row power folding seat control unit harness connector B402 terminals 16, 18, 21 and ground.
Do all terminals have ground?
YES >> Inspection End.
NO >> Check harness for ground.
Unit Power source Fuse or Fusible Link Location
Third row power folding seat control unit Battery
F
Fuse and fusible link box
19 Fuse block (J/B)
Ignition switch ON or START 14
TerminalsIgnition switch position
(+) (–) OFF ON START
Connector Terminal
A: B401 1
Ground Battery
voltage
80 VBattery
voltage
B: B402 13
Battery
voltage
14 Battery
voltage
ALJIA0274ZZ
Te r m i n a l s
Continuity
(+)
(–)
Connector Terminal
B402 16
Ground Yes
18
21
ALJIA0275ZZ
Revision: March 2010 2008 QX56

THIRD SEATSE-19
< COMPONENT DIAGNOSIS >
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Third Row Power Folding Seat SwitchINFOID:0000000001735719
1.CHECK THIRD ROW POWER FOLD ING SEAT SWITCH OPERATION
1. Turn ignition switch OFF.
2. Disconnect third row power folding seat switch.
3. Check continuity between third row power folding seat switch terminals 2, 3 and 4.
Do you have continuity?
YES >> Inspection End.
NO >> Replace third row power folding seat switch.
Third Row Power Folding Seat MotorINFOID:0000000001735720
1.CHECK MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect third row power folding seat motor connector B403 or B426.
3. Check operation by applying battery voltage to motor terminals 3 and 4.
CAUTION:
• Do not operate motor for more than 3 seconds.
• Be careful not to overheat the harness.
• Third row power folding seat control unit may have to
relearn fold up/down positions after testing.
Does the motor rotate in both directions?
YES >> GO TO 2.
NO >> Replace third row power seat motor. Refer to SE-60, "
Exploded View".
2.CHECK RESISTANCE IN MOTOR
Terminals Condition Continuity
2 4 Press switch button to fold up. Yes
3 4 Press switch button to fold down. Yes
ALJIA0089ZZ
LH (60%) seat
Terminal MotorSeat
3 (Battery positive) - 4 (Battery negative) Rotates counter-clockwise Up
4 (Battery positive) - 3 (Battery negative) Rotates clockwise Down
AWJIA0359ZZ
RH (40%) seat
Terminal MotorSeat
3 (Battery positive) - 4 (Battery negative) Rotates counter-clockwise Down
4 (Battery positive) - 3 (Battery negative) Rotates clockwise Up
Revision: March 2010 2008 QX56