suspension INFINITI QX56 2010 Factory Repair Manual

SCS-6
< FUNCTION DIAGNOSIS >
SUSPENSION CONTROL SYSTEM
Component Parts Location
INFOID:0000000005148148
:Front
Component DescriptionINFOID:0000000005148149
1. Suspension control unit B3 (view with upper and lower luggage side finishers
LH removed) 2. Suspension air compressor C9 (view
under vehicle behind LH rear suspen-
sion) 3. Height sensor C8 (view under vehicle
at LH rear suspension)
4. Compressor motor relay E130, E131 (view with battery removed)
ALEIA0044ZZ
Part name Description
Suspension control unit • Monitors height sensor input to determine vehicle height.
• Actuates the compressor motor relay or exhaust valve solenoid to raise or
lower the vehicle accordingly.
• Sends a ground signal to the combination meter to activate the CK SUSP indicator lamp.
Suspension air compressor (with built in exhaust valve
solenoid) • When the compressor is actuated, it pumps air into the system to raise the
rear suspension.
• When the exhaust valve solenoid is actuated, it vents air from the system to lower the rear suspension.
Height sensor Provides vehicle height input to the suspension control unit.
Revision: April 20092010 QX56

DIAGNOSIS SYSTEM (SUSPENSION CONTROL UNIT)
SCS-7
< FUNCTION DIAGNOSIS >
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DIAGNOSIS SYSTEM (SUS PENSION CONTROL UNIT)
CONSULT-III FunctionINFOID:0000000005148150
CONSULT-III can display each diagnostic item using the diagnostic test modes shown following.
WORK SUPPORT
Display Item List
DATA MONITOR
Display Item List
ACTIVE TEST
CAUTION:
Do not perform active test while driving.
Display Item List
AIR LEVELIZER diagnosis mode Description
WORK SUPPORT Supports inspection and adjustment. Commands are transmitted to the suspension control
unit for setting the status suitable for required operation, input/output signals are received
from the suspension control unit 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 The part number of suspension control unit can be checked.
ItemDescription Condition
STANDARD HEIGHT LEVEL Resets the vehicle height to the initialization flag
setting stored in the suspension control unit. Vehicle unladen, set in a horizontal position and
not moving.
NOTE:
Do not take your eyes off the vehicle while CON-
SULT-III is processing.
ADJUST HEIGHT INI Sets the height initialization flag in the suspen-
sion control unit when the control unit has been
replaced or when the initialization flag has been
cleared using the "CLEAR HEIGHT INI" proce-
dure. Vehicle unladen, move vehicle forward and back-
ward approx. 5 m (16.4 ft) and rock vehicle side
to side.
NOTE:
Do not move vehicle wh
ile CONSULT-III is pro-
cessing.
CLEAR HEIGHT INI Clears the initialization flag in the suspension
control unit. Vehicle unladen.
Display item [unit] ALL
SIGNALS SELECTION FROM MENU
HEIGT SEN [V] XX
HEIGT CALC [mm] XX
SEN FIX TIME [HR] XX
HEIGT INI VAL [V] XX
COMPRESSOR [ON/OFF] XX
EXH SOLENOID [ON/OFF] XX
ACG L [ON/OFF] XX
Test Item Description
COMPRESSOR ON/OFF
Revision: April 20092010 QX56

SCS-8
< FUNCTION DIAGNOSIS >
DIAGNOSIS SYSTEM (SUSPENSION CONTROL UNIT)
CAUTION:
The "COMPRESSOR active test will remain ON until it is turned off using CONSULT-III. Allowing the
compressor to run for an extended period of time may cause damage to the suspension control sys-
tem components due to excessive pressure.
NOTE:
• "TEST IS STOPPED" is displayed approximately 10 seconds after operation starts for all active test items except "COMPRESSOR".
• After "TEST IS STOPPED" is display ed, to perform test again, repeat step 6.
EXHAUST SOLENOID ON/OFF
WARNING LAMP ON/OFF
Revision: April 20092010 QX56

C1801 VEHICLE HEIGHT SENSORSCS-9
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COMPONENT DIAGNOSIS
C1801 VEHICLE HEIGHT SENSOR
DescriptionINFOID:0000000005148151
The vehicle height sensor operates on a 5 volt referenc e signal from the suspension control unit. The suspen-
sion control unit also provides ground to the height sensor. Depending on vehicle height, the height sensor
signal should have between 0.2V and 4.8V.
DTC LogicINFOID:0000000005148152
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000005148153
1.CHECK HEIGHT SENSOR OPERATION
CONSULT-III
1. Turn ignition switch ON
2. Select "HEIGT SEN" of AIR L EVELIZER data monitor test item.
Is the HEIGHT SEN voltage within the given range?
YES >> Height sensor is operating normally.
NO >> Refer to SCS-23, "
Diagnosis Procedure".
DTC CONSULT-III Diagnostic item is detected when ... Probable malfunction location
C1801 VEHICLE HEIGHT SEN-
SOR Vehicle height sensor voltage is less than 0.2V
or greater than 4.8V for more than 60 seconds. • Height sensor power/ground supply. Refer to
SCS-18, "
HEIGHT SENSOR : Diagnosis
Procedure".
• Height sensor signal circuit. Refer to SCS-
23, "Component Function Check".
HEIGHT SEN : 0.2V - 4.8V
Revision: April 20092010 QX56

SCS-10
< COMPONENT DIAGNOSIS >
C1802 COMPRESSOR RELAY
C1802 COMPRESSOR RELAY
DescriptionINFOID:0000000005148154
The compressor motor relay is controlled by the suspension control unit. The suspension control unit supplies
voltage to the coil side of the relay to activate it. T he compressor motor relay, when activated, supplies power
to the suspension air compressor.
DTC LogicINFOID:0000000005148155
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000005148156
1.CHECK COMPRESSOR MOTOR RELAY OPERATION
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-III. Allowing the
compressor to run for an extended period of time may cause damage to the air levelizer system com-
ponents due to excessive air pressure.
CONSULT-III
1. Turn ignition ON.
2. Select "COMPRESSOR" of AIR LEVELIZER active test items.
3. While operating test item, check that the suspension air compressor turns ON.
Does the suspension air compressor operate properly?
YES >> Compressor motor relay and suspension air compressor are operating normally.
NO >> Refer to SCS-20, "
Diagnosis Procedure".
DTC CONSULT-III Diagnostic item is detected when ... Probable malfunction location
C1802 COMPRESSOR RELAY • Driving transistor for the compressor
relay is
OFF and monitor voltage continues at a high
level for more than 10 seconds.
• Driving transistor for the compressor relay is
ON and monitor voltage continues at a low
level for more than 5 seconds. Compressor motor relay. Refer to
SCS-20,
"Component Function Check".
ON : Compressor turns ON
OFF : Compressor turns OFF
Revision: April 20092010 QX56

C1803 EXHAUST SOLENOIDSCS-11
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C1803 EXHAUST SOLENOID
DescriptionINFOID:0000000005148157
The exhaust valve solenoid controls the vent function of the suspensi on control system. The exhaust valve
solenoid is built into the suspension air compressor. The suspension control unit supplies voltage to the
exhaust valve solenoid to activate it.
DTC LogicINFOID:0000000005148158
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000005148159
1.CHECK EXHAUST SOLENOID OPERATION
CAUTION:
While operating this active test, the suspension control system wil l vent air pressure and the vehicle
ride height will lower. Ensure th e area around the vehicle is free from obstructions before beginning
test.
CONSULT-III
1. Ensure the suspension control system has air pressure and is not drooping in the rear.
2. Select "EXHAUST SOLENOID" of AIR LEVELIZER active test items.
3. While operating test item, check that the exhaust va lve solenoid opens to vent air from the system. The
vehicle should lower when the exhaust valve solenoid is activated.
Does the system vent properly?
YES >> Exhaust valve solenoid is operating normally.
NO >> Refer to SCS-24, "
Description".
DTC CONSULT-III Diagnostic item is detected when ... Probable malfunction location
C1803 EXHAUST SOLENOID • Driving transistor for the exhaust valve sole-
noid is OFF and monitor voltage continues at
a high level for more than 10 seconds.
• Driving transistor for the exhaust valve sole- noid is ON and monitor voltage continues at
a low level for more than 5 seconds. Open or short circuit in the exhaust valve sole-
noid control circuit. Refer to
SCS-24, "
Compo-
nent Function Check".
ON : Air vents and vehicle ride height lowers
OFF : No air vents and vehicle ride height remains constant
Revision: April 20092010 QX56

SCS-12
< COMPONENT DIAGNOSIS >
C1804 HEIGHT ADJUSTING MALFUNCTION (COMPRESSOR)
C1804 HEIGHT ADJUSTING MA LFUNCTION (COMPRESSOR)
DescriptionINFOID:0000000005148160
The compressor motor relay is controlled by the sus pension control unit. The suspension control unit supplies
voltage to the coil side of the relay to activate it. T he compressor motor relay, when activated, supplies power
to the suspension air compressor.
DTC LogicINFOID:0000000005148161
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000005148162
1.CHECK COMPRESSOR MOTOR RELAY OPERATION
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-III. Allowing the
compressor to run for an extended period of time may cause damage to the air levelizer system com-
ponents due to excessive air pressure.
CONSULT-III
1. Turn ignition ON.
2. Select "COMPRESSOR" of AIR LEVELIZER active test items.
3. While operating test item, check that the suspension air compressor turns ON.
Does the suspension air compressor operate properly?
YES >> Compressor motor relay and suspension air compressor are operating normally.
NO >> Refer to SCS-20, "
Diagnosis Procedure".
DTC CONSULT-III Diagnostic item is detected when ... Probable malfunction location
C1804 VEHICLE HEIGHT AD-
JUSTING MALFUNC-
TION (COMPRESSOR) Continuous compressor relay ON time is more
than 120 seconds.
Compressor motor relay. Refer to
SCS-20,
"Component Function Check".
ON : Compressor turns ON
OFF : Compressor turns OFF
Revision: April 20092010 QX56

C1805 HEIGHT ADJUSTING MALFUNCTION (EXH SOLENOID)
SCS-13
< COMPONENT DIAGNOSIS >
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C1805 HEIGHT ADJUSTING MALF UNCTION (EXH SOLENOID)
DescriptionINFOID:0000000005148163
The exhaust valve solenoid controls the vent function of the suspensi on control system. The exhaust valve
solenoid is built into the suspension air compressor. The suspension control unit supplies voltage to the
exhaust valve solenoid to activate it.
DTC LogicINFOID:0000000005148164
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000005148165
1.CHECK EXHAUST SOLENOID OPERATION
CAUTION:
While operating this active test, the suspension control system wil l vent air pressure and the vehicle
ride height will lower. Ensure th e area around the vehicle is free from obstructions before beginning
test.
CONSULT-III
1. Ensure the suspension control system has air pressure and is not drooping in the rear.
2. Select "EXHAUST SOLENOID" of AIR LEVELIZER active test items.
3. While operating test item, check that the exhaust va lve solenoid opens to vent air from the system. The
vehicle should lower when the exhaust valve solenoid is activated.
Does the system vent properly?
YES >> Exhaust valve solenoid is operating normally.
NO >> Refer to SCS-24, "
Description".
DTC CONSULT-III Diagnostic item is detected when ... Probable malfunction location
C1805 VEHICLE HEIGHT AD-
JUSTING MALFUNC-
TION (EXHAUST
SOLENOID) Continuous exhaust valve solenoid ON time is
more than 120 seconds.
Short to power in the exhaust valve solenoid
control circuit. Refer to
SCS-24, "
Component
Function Check".
ON : Air vents and vehicle ride height lowers
OFF : No air vents and vehicle ride height remains constant
Revision: April 20092010 QX56

SCS-14
< COMPONENT DIAGNOSIS >
C1806 VEHICLE HEIGHT SENSOR LOCKING MALFUNCTION
C1806 VEHICLE HEIGHT SENSOR LOCKING MALFUNCTION
DescriptionINFOID:0000000005148166
The vehicle height sensor operates on a 5 volt referenc e signal from the suspension control unit. The suspen-
sion control unit also provides ground to the height sensor.
DTC LogicINFOID:0000000005148167
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000005148168
1.CHECK HEIGHT SENSOR OPERATION
CONSULT-III
1. Turn ignition switch ON
2. Select "HEIGT SEN" of AIR LEVELIZER data monitor test item.
Is the HEIGHT SEN voltage within the given range?
YES >> Height sensor is operating normally.
NO >> Refer to SCS-23, "
Diagnosis Procedure".
DTC CONSULT-III Diagnostic item is detected when ... Probable malfunction location
C1806 VEHICLE HEIGHT SEN-
SOR LOCKING MAL-
FUNCTION Output sensor voltage variation
±0.02V is more
than 100 seconds when vehicle height range is
normal. • Height sensor power/ground supply. Refer to
SCS-18, "
HEIGHT SENSOR : Diagnosis
Procedure".
• Charging system malfunction. Refer to CHG-
8, "Inspection Procedure".
HEIGHT SEN : 0.2V - 4.8V with no more than ± 0.02V
variation
Revision: April 20092010 QX56

C1807 SENSOR 5V MALFUNCTIONSCS-15
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C1807 SENSOR 5V MALFUNCTION
DescriptionINFOID:0000000005148169
The vehicle height sensor operates on a 5 volt referenc e signal from the suspension control unit. The suspen-
sion control unit also provides ground to the height sensor.
DTC LogicINFOID:0000000005148170
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000005148171
Regarding Wiring Diagram information, refer to SCS-29, "Wiring Diagram".
1.POWER SUPPLY CIRCUIT CHECK
1. Disconnect height sensor connector C8.
2. Turn the ignition switch ON.
3. Check voltage between the height sensor connector C8 terminal 1 and ground.
Is 5V present?
YES >> System is working normally.
NO >> Check harness or connector for open or short. If OK, replace the suspension control unit. Refer to RSU-26, "
Removal and Installation".
DTC CONSULT-IIIDiagnostic item is detected when ... Probable malfunction location
C1807 SENSOR 5V MALFUNC-
TION Sensor reference voltage is less than 0.8V or
more than 6V for 20 seconds. • Height sensor power/ground supply. Refer to
SCS-18, "
HEIGHT SENSOR : Diagnosis
Procedure".
• Charging system malfunction. Refer to CHG-
8, "Inspection Procedure".
(+)
(-) Voltage
Connector Terminal
C8 1 Ground 5V
ALEIA0026GB
Revision: April 20092010 QX56