2009 INFINITI QX56 air suspension

CK SUSP WARNING INDICATOR CONTROL CIRCUITSCS-25
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CK SUSP WARNING INDICATOR CONTROL CIRCUIT
DescriptionINFOID:0000000003772348
The CK SUSP warning lamp is controlled by a ground signal provided to the combination meter by the sus-
pension control unit.
Component Function CheckINFOID:0000000003772349
1.CHECK WARNING LAMP OPERATION
CONSULT-III
1. Turn ignition ON.
2. Select "WARNING LAMP" of AI R LEVELIZER active test items.
3. While operating test item, check that the warning lamp activates.
Does the warning lamp operate properly?
YES >> Warning lamp is operating normally.
NO >> Refer to SCS-25, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000003772350
1.PERFORM SUSPENSION CONTROL SYSTEM SELF-DIAGNOSIS
CONSULT-III
1. Turn ignition ON.
2. Perform SELF DIAGNOSIS function of AIR LEVELIZER system.
Are any DTC's present?
YES >> Refer to SCS-33, "DTC Index".
NO >> • If warning lamp is always ON, GO TO 2. • If warning lamp is always OFF, GO TO 3
2.CHECK SUSPENSION CONTROL UNIT WARNING LAMP CONTROL
1. Turn ignition OFF.
2. Disconnect the suspension control unit connector B3.
3. Turn ignition ON.
Does the CK SUSP warning lamp turn ON?
YES >> GO TO 3.
NO >> Replace the suspension control unit. Refer to RSU-26, "
Removal and Installation".
3.CHECK CONTINUITY OF WARNING LAMP CONTROL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3 and combina- tion meter connector M24.
3. Check continuity between suspension control unit connector B3 (A) terminal 10 and combination meter connector M24 (B) termi-
nal 15.
4. Check continuity between suspension control unit connector B3 (A) terminal 10 and ground.ON : Warning lamp turns ON
OFF : Warning lamp turns OFF
AB
Continuity
Connector Terminal Connector Terminal
B3 10 M24 15 Yes
ALLIA0693GB
Revision: December 20092009 QX56

SUSPENSION CONTROL UNITSCS-27
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ECU DIAGNOSIS
SUSPENSION CONTROL UNIT
Reference ValueINFOID:0000000003772351
TERMINAL LAYOUT
PHYSICAL VALUES
AWLIA1640ZZ
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: December 20092009 QX56

SCS-34
< ECU DIAGNOSIS >
SUSPENSION CONTROL UNIT
Compressor relay [C1802]• Driving transistor for compre
ssor relay is OFF and monitor
voltage continues at a high level for more than 10 seconds.
• Driving transistor for compre ssor relay is ON and monitor
voltage continues at a low level for more than 5 seconds. SCS-10, "DiagnosisProcedure".
Exhaust solenoid [C1803] • Driving transistor for exhaust valve solenoid is OFF and
monitor voltage continues at a high level for more than 10
seconds.
• Driving transistor for exhaust valve solenoid is ON and mon- itor voltage continues at a low level for more than 5 seconds. SCS-11,
"DiagnosisProcedure".
Vehicle height adjusting malfunc-
tion (compressor)[C1804] Continuous compressor relay ON time is more than 120 sec-
onds. SCS-12,
"DiagnosisProcedure".
Vehicle height adjusting malfunc-
tion (exhaust solenoid)[C1805] Continuous exhaust valve solenoid ON time is more than 120
seconds. SCS-13,
"DiagnosisProcedure".
Vehicle height sensor locking mal-
function [C1806] Output sensor voltage variation
±0.02V is more than 100 sec-
onds when vehicle height range is normal. SCS-14, "
Diagnosis Proce-
dure".
Sensor 5V malfunction [C1807] Sensor reference voltage is less than 0.8V or more than 6V for
20 seconds. SCS-15,
"DiagnosisProcedure"
Integral time malfunction by sup-
plying air [C1808]A suspension air compressor ON request has been in effect
for 180 seconds and the suspension air compressor has not
activated during that time. SCS-16,
"DiagnosisProcedure".
Revision: December 20092009 QX56

SUSPENSION CONTROL SYSTEMSCS-35
< SYMPTOM DIAGNOSIS >
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SYMPTOM DIAGNOSIS
SUSPENSION CONTROL SYSTEM
Symptom TableINFOID:0000000003772354
AIR LEVELIZER
Symptom Possible causeReference page
Inoperative • Suspension control unit
• Compressor motor relay
• Suspension air compressorSCS-36, "
Diagnosis Proce-
dure"
System does not raise • Suspension control unit
• Height sensor
• Compressor motor relay
• Suspension air compressor
• Leak in system
• Restriction in systemSCS-37, "Diagnosis Proce-
dure"
System does not lower
• Suspension control unit
• Height sensor
• Compressor motor relay
• Suspension air compressor
• Restriction in systemSCS-38, "Diagnosis Proce-
dure"
CK SUSP indicator lamp always ON with key ON
• CK SUSP indicator lamp control circuit
• Suspension control unitSCS-25, "Description"
Revision: December 20092009 QX56

SCS-36
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM INOPERATIVE
SUSPENSION CONTROL SYSTEM INOPERATIVE
DescriptionINFOID:0000000003772355
The suspension control system does not activate. It does not raise or lower the vehicle in response to ride
height changes.
Diagnosis ProcedureINFOID:0000000003772356
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-12, "
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: December 20092009 QX56

SUSPENSION CONTROL SYSTEM DOES NOT RAISE
SCS-37
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SUSPENSION CONTROL SYST EM DOES NOT RAISE
DescriptionINFOID:0000000003772357
The suspension control system does not raise the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000003772358
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: December 20092009 QX56

SCS-38
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
DescriptionINFOID:0000000003772359
The suspension control system does not lower the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000003772360
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: December 20092009 QX56

PRECAUTIONSSCS-39
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000005867805
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:0000000003772362
• 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: December 20092009 QX56