engine INFINITI QX56 2011 Factory Service Manual

SCS-66
< BASIC INSPECTION >[AIR LEVELIZER CONTROL SYSTEM]
DIAGNOSIS AND REPAIR WORKFLOW
YES >> GO TO 7.
NO >> Check harness and connectors based on the information obtained by interview. Refer to
GI-40,
"Intermittent Incident".
7.FINAL CHECK
With CONSULT-III
1. Check the reference value for “E-SUS”.
2. Recheck the symptom and check that the symp tom is not reproduced on the same conditions.
Is the symptom reproduced?
YES >> GO TO 3.
NO >> INSPECTION END
Diagnostic Work SheetINFOID:0000000006256059
Description
 In general, customers have their own criteria for a pr oblem. Therefore, it is important to understand the
symptom and status well enough by asking the customer about his/her concerns carefully. To systemize all
the information for the diagnosis, prepare the inte rview sheet referring to the interview points.
 In some cases, multiple conditions that appear simultaneously may cause a DTC to be detected.
INTERVIEW SHEET SAMPLE
Interview sheet
Custmer
name MR/MS Registration
number Initial year
registration
Vehicle type VIN
Storage date Engine Mileage km/Mile
Symptom † Does not operate ( ) function
† Warning lamp for ( ) turns ON
† Noise † Vibration
† Other
( )
First occurrence † Recently † Other ( )
Frequency of occurrence † Always † Under a certain conditions of † Sometimes ( time/day)
Climate con-
ditions †
Irrelevant
Weather † Fine † Cloud † Rain † Snow † Others ( )
Temperature † Hot † Warm † Cool † Cold † Temp. [Approx. °C ( °F)]
Relative humidity † High † Moderate † Low
Road conditions † Urban area † Suburb area † Highway
† Mountainous road (uphill or downhill) † Rough road
Operating condition, etc. † Irrelevant
† When engine starts † During idling
† During driving † During acceleration † At constant speed driving
† During deceleration
† During cornering (righ t curve or left curve)
† When steering wheel is steered (to right or to left)
Memo
Revision: 2010 May2011 QX56

STANDARD VEHICLE HEIGHT SETTINGSCS-67
< BASIC INSPECTION > [AIR LEVELIZER CONTROL SYSTEM]
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STANDARD VEHICL E HEIGHT SETTING
DescriptionINFOID:0000000006256060
Air levelizer control module enables precise control, by acquiring memorized standard vehicle height and sig-
nal (vehicle height) from vehicle height sensor. For this reason, always set standard vehicle height after per-
forming the following operations.
 Removal and installation or replacement of vehicle height sensor
 Replacement of air levelizer control module
Work ProcedureINFOID:0000000006256061
1.CLEAR STANDARD VEHICLE HEIGHT
With CONSULT-III
1. Lift up the vehicle. CAUTION:
Check that tires never contact the ground.
2. Start the engine.
3. Select “COMPRESSOR” in “Active Test” in “E-SUS”.
4. Touch “ON” and wait 60 seconds or more.
5. Touch “OFF”.
6. Select “CLEAR HEIGHT INI” in “Work Support” in “E-SUS”.
7. Touch “Start”.
8. Touch “Clear”. NOTE:
CONSULT-III continues indicating "EXECUTING". The completion of the standard vehicle height erasing
can be checked by the CK SUSP indicator lamp ON condition.
Does CK SUSP indicator lamp turn ON?
YES >> GO TO 2.
NO >> Perform step 1 again.
2.ADJUST STANDARD VEHICLE HEIGHT
With CONSULT-III
1. Select “ADJUST HEIGHT INI” in “Work Support” in “E-SUS”.
2. Touch “Start”.
3. Touch “Initial 1”. NOTE:
CONSULT-III continues indicating "EXECUTING". T he completion of the standard vehicle height adjust-
ment can be checked by the CK SUSP indicator lamp OFF condition.
Does CK SUSP indicator lamp turn OFF?
YES >> GO TO 3.
NO >> Perform step 1 again.
3. ADJUST VEHICLE HEIGHT
With CONSULT-III
1. Lift down the vehicle. CAUTION:
Check that the lift is fully lowered.
2. Select “STANDARD HEIGHT LEVEL” in “Work Support” in “E-SUS”.
3. Touch “Start”.
4. Touch “Revert” and wait 120 seconds or more.
5. Although CONSULT-III continues indicating "EXECUTIN G", select “VHCL HGT CNVSN VL” in “Data Mon-
itor” in “E-SUS”.
Is value within
−15 – 15 mm?
YES >> GO TO 4.
NO >> Perform step 1 again.
4.CHECK DTC
With CONSULT-III
Revision: 2010 May2011 QX56

C1801 VHCL HEIGHT SENSORSCS-69
< DTC/CIRCUIT DIAGNOSIS > [AIR LEVELIZER CONTROL SYSTEM]
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DTC/CIRCUIT DIAGNOSIS
C1801 VHCL HEIGHT SENSOR
DTC LogicINFOID:0000000006256062
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Turn ignition switch ON and wait 60 seconds or more.
2. Perform “Self Diagnostic Results” in “E-SUS”.
Is
“C1801” detected ?
YES >> Go to SCS-69, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256063
1.CHECK APPEARANCE
Visually check for malfunction of suspension components, installing malfunction, or deformation of vehicle
height sensor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repaire or replace damaged parts.
2.CHECK POWER SUPPLY CIRCUIT (PART 1)
1. Disconnect vehicle height sensor connector.
2. Turn ignition switch ON. CAUTION:
Never start the engine.
3. Check voltage between vehicle height sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.CHECK POWER SUPPLY CIRCUIT (PART 2)
1. Turn ignition switch OFF.
2. Disconnect air levelizer control module connector.
DTC Display itemI Malfunction detected condition Possible cause
C1801 VHCL HEIGHT SENSOR Signal voltage of the vehicle height sensor remains 0.2
V or less or 4.6 V or more continuously for 60 seconds
during sensor voltage (4.5 – 5.5 V) output by the air lev-
elizer control module.  Harness or connectors
(Sensor circuit is open.)
 Vehicle height sensor
 Air levelizer control module
 Rear suspension component parts
Vehicle height sensor —Voltage
Connector Terminal
C13 1 Ground 4.5 – 5.5 V
Revision: 2010 May2011 QX56

SCS-72
< DTC/CIRCUIT DIAGNOSIS >[AIR LEVELIZER CONTROL SYSTEM]
C1802 AIR SUS COMPRS RELAY
C1802 AIR SUS COMPRS RELAY
DTC LogicINFOID:0000000006256065
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Turn ignition switch ON and wait 10 seconds or more.
2. Select “COMPRESSOR” in “Active Test” in “E-SUS”.
3. Touch “ON” and wait 5 seconds or more.
4. Select “Self Diagnostic Result” in “E-SUS”.
Is
“C1802” detected ?
YES >> Go to SCS-72, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256066
1.CHECK AIR COMPRESSOR ON SIGNAL FROM AIR LEVELIZER CONTROL MODULE
CONSULT-III
1. Disconnect air compressor relay connector.
2. Turn ignition switch ON. CAUTION:
Never start the engine.
3. Select “COMPRESSOR” in “Active Test” in “E-SUS”.
4. Touch “ON”.
5. While operating test item, check voltage betw een air compressor relay harness connector and ground.
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN AIR LEVELIZER CO NTROL MODULE AND AIR COMPRESSOR RELAY
1. Turn ignition switch OFF.
2. Disconnect air levelizer control module connector.
DTC Display item Malfunction detected condition Possible cause
C1802 AIR SUS COMPRS RELAY  Output voltage of the air compressor relay remains
9 V or less continuously for 5 seconds during air
compressor ON signal output by the air levelizer
control module.
 Output voltage of the air compressor relay remains
2 V or more continuously for 10 seconds during air
compressor OFF signal output by the air levelizer
control module.  Harness or connector
 Air compressor relay
 Air levelizer control module
Air compressor relay
—Voltage
Connector Terminal
E116 2 Ground 9 – 16 V
Revision: 2010 May2011 QX56

SCS-74
< DTC/CIRCUIT DIAGNOSIS >[AIR LEVELIZER CONTROL SYSTEM]
C1803 AIR SUSPENSION EXH SOL
C1803 AIR SUSPENSION EXH SOL
DTC LogicINFOID:0000000006256067
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Turn ignition switch ON and wait 10 seconds or more.
2. Select “EXHAUST SOLENOID” in “Active Test” in “E-SUS”.
3. Touch “ON” and wait 5 seconds or more.
4. Select “Self Diagnostic Result” in “E-SUS”.
Is
“C1803” detected ?
YES >> Go to SCS-74, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256068
1.CHECK EXHAUST SOLENOID ON SIGNAL FROM AIR LEVELIZER CONTROL MODULE
CONSULT-III
1. Disconnect air compressor harness connector.
2. Turn ignition switch ON. CAUTION:
Never start the engine.
3. Select “EXHAUST SOLENOID” in “Active Test” in “E-SUS”.
4. Touch “ON”.
5. While operating test item, check voltage bet ween air compressor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN AIR LEVELIZE R CONTROL MODULE AND AIR COMPRESSOR
1. Turn ignition switch OFF.
2. Disconnect air levelizer control module harness connector.
DTC Display item Malfunction detected condition Possible cause
C1803 AIR SUS EXH SOL  Output voltage of the exhaust solenoid remains 9 V
or less continuously for 5 seconds during exhaust
solenoid ON signal output by the air levelizer con-
trol module.
 Output voltage of the exhaust solenoid remains 2 V
or more continuously for 10 seconds during ex-
haust solenoid ON signal output by the air levelizer
control module.  Harness or connector
 Exhaust solenoid
 Air levelizer control module
Air compressor
—Voltage
Connector Terminal
C12 4 Ground 9 – 16 V
Revision: 2010 May2011 QX56

C1804 VHCL HEIGHT ADJ UPSCS-77
< DTC/CIRCUIT DIAGNOSIS > [AIR LEVELIZER CONTROL SYSTEM]
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C1804 VHCL HEIGHT ADJ UP
DTC LogicINFOID:0000000006256070
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Set vehicle in the unloaded vehicle status.
2. Start the engine and wait 150 seconds or more.
3. Perform “Self Diagnostic Result” in “E-SUS”.
Is
“C1804” detected ?
YES >> Go to SCS-77, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256071
1.CHECK APPEARANCE
Visually check for malfunction of suspension component s, damage of air chamber of rear shock absorber,
installation malfunction, or defo rmation of vehicle height sensor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repaire or replace damaged parts.
2.CHECK AIR LEAK
Apply soapy water to air tube, connecting portions between air tube and each component, and air chamber of
rear shock absorber. Check for air leakage.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repaire or replace damaged parts.
3.CHECK AIR COMPRESSOR RELAY POWER SUPPLY
1. Turn ignition switch OFF.
2. Check 30A fuse (#I).
3. Disconnect air compressor relay connector.
4. Check voltage between air compressor relay harness connector and ground.
DTC Display item Malfunction detected condition Possible cause
C1804 VHCL HEIGHT ADJ UP The vehicle height is 15 mm (0.59 in) or more lower
than the reference height despite the output of air
compressor ON signal continuously for 120 seconds
by the air levelizer control module.  Harness or connector
Air compressor
 Air compressor relay
 Air levelizer control module
 Rear shock absorber (air cham-
ber)
 Vehicle height sensor
 Air tube
 Rear suspension component parts
 Overloaded
Revision: 2010 May2011 QX56

SCS-80
< DTC/CIRCUIT DIAGNOSIS >[AIR LEVELIZER CONTROL SYSTEM]
C1805 VHCL HE
IGHT ADJ DOWN
C1805 VHCL HEIGHT ADJ DOWN
DTC LogicINFOID:0000000006256074
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Start the engine and wait 150 seconds or more.
2. Perform “Self Diagnostic Result” in “E-SUS”.
Is
“C1805” detected ?
YES >> Go to SCS-80, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256075
1.CHECK APPEARANCE
Visually check for malfunction of suspension components, crush of air tube, installation malfunction, or defor-
mation of vehicle height sensor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repaire or replace damaged parts.
2.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> Perform “STANDARD VEHICLE HEIGHT SETTING”. Refer to SCS-67, "Work Procedure".
NO >> Repair or replace damaged part.
DTC Display item Malfunction detected condition Possible cause
C1805 VHCL HEIGHT ADJ DOWN The vehicle height is 15 mm (0.59 in) or more raise than
the reference height despite the output of exhaust sole-
noid ON signal continuously for 120 seconds by the air
levelizer control module.  Harness or connector
 Vehicle height sensor
Air compressor
(exhaust sole-
noid)
Air tube
 Rear suspension component
parts
Revision: 2010 May2011 QX56

C1806 VHCL HEIGHT SEN FIXSCS-81
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C1806 VHCL HEIGHT SEN FIX
DTC LogicINFOID:0000000006256076
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK VEHICLE HEIGHT SENSOR FIXATION
With CONSULT-III
1. Start the engine.
2. Select “VHCL HEIGHT SEN” in “Data Monitor” in “E-SUS”.
3. Drive vehicle and maintain the following conditions for 5 minutes or more.
Does the value of
“VHCL HEIGHT SEN” change?
YES >> INSPECTION END
NO >> Go to SCS-81, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000006256077
1.CHECK APPEARANCE
Visually check for installation malfunction, or deformation of vehicle height sensor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repaire or replace damaged parts.
2.CHECK VEHICLE HEIGHT SENSOR
Check the vehicle height sensor. Refer to SCS-70, "
Component Inspection".
Is the inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
NO >> Replace the vehicle height sensor. Refer to SCS-98, "
Removal and Installation".
DTC Display item Malfunction detected condition Possible cause
C1806 VHCL HEIGHT SEN FIX The signal voltage of the vehicle height sensor does
not change for cumulated time of 100 hours under the
condition that the air levelizer control module outputs
sensor voltage (4.5 – 5.5 V) with vehicle speeds 2
km/h (2 MPH) or more.  Harness or connector
 Vehicle height sensor
Vehicle speed : 5 km/h (3 MPH) or more
Revision: 2010 May2011 QX56

SCS-82
< DTC/CIRCUIT DIAGNOSIS >[AIR LEVELIZER CONTROL SYSTEM]
C1807 VHCL HEIGHT SEN VOLT
C1807 VHCL HEIGHT SEN VOLT
DTC LogicINFOID:0000000006256078
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Turn ignition switch ON and wait 20 seconds or more.
2. Perform “Self Diagnostic Results” in “E-SUS”.
Is
“C1807” detected ?
YES >> Go to SCS-82, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256079
1.CHECK POWER SUPPLY CIRCUIT (PART 1)
1. Disconnect vehicle height sensor connector.
2. Turn ignition switch ON. CAUTION:
Never start the engine.
3. Check voltage between the vehicle height sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK POWER SUPPLY CIRCUIT (PART 2)
1. Turn ignition switch OFF.
2. Disconnect air levelizer control module connector.
3. Check continuity between air levelizer control m odule harness connector and vehicle height sensor har-
ness connector.
DTC Display item Malfunction detected condition Possible cause
C1807 VHCL HEIGHT SEN VOLT The sensor power supply is more than 5.5 V or less
than 4.5 V continuously for 20 seconds when the ig-
nition switch is ON.
 Harness or connector
 Vehicle height sensor
 Air levelizer control module
Sensor power supply is 0.5 V or more continuously for
1 second during 2 seconds after turning ON the igni-
tion switch.
Vehicle height sensor
—Voltage
Connector Terminal
C13 1 Ground 4.5 – 5.5 V
Air levelizer control module Vehicle height sensor Continuity
Connector Terminal Connector Terminal
B84 13 C13 1 Existed
Revision: 2010 May2011 QX56

SCS-84
< DTC/CIRCUIT DIAGNOSIS >[AIR LEVELIZER CONTROL SYSTEM]
C1808 AIR SUS COMPRS FNCTN
C1808 AIR SUS COMPRS FNCTN
DTC LogicINFOID:0000000006256080
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” has been previous ly conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Set vehicle in the unloaded vehicle status.
2. Start the engine and wait 5 minutes or more.
3. Perform “Self Diagnostic Result” in “E-SUS”.
Is
“C1808” detected ?
YES >> Go to SCS-84, "DiagnosisProcedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256081
1.CHECK APPEARANCE
Visually check for malfunction of suspension component s, damage of air chamber of rear shock absorber,
installation malfunction, or deformation of vehicle height sensor.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repaire or replace damaged parts.
2.CHECK AIR LEAK
Apply soapy water to air tube, connecting portions between air tube and each component, and air chamber of
rear shock absorber. Check for air leakage.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repaire or replace damaged parts.
3.CHECK AIR COMPRESSOR RELAY POWER SUPPLY
1. Turn ignition switch OFF.
2. Check 30A fuse (#I).
3. Disconnect air compressor relay connector.
4. Check voltage between air compressor relay harness connector and ground.
DTC Display item Malfunction detected condition Possible cause
C1808 AIR SUS COMPRS FNCTN The cumulative operating time of the air compressor
reaches 180 seconds or more.
NOTE:
Cumulative time is cleared under the following condi-
tions:
 Ignition switch: OFF
 Exhaust conditions: satisfied [Vehicle height re-
mains 15 mm (0.59 in) or more higher than the ref-
erence height for 30 seconds.]  Harness or connector
 Vehicle height sensor
 Air compressor (exhaust sole-
noid)
 Air compressor relay
 Overloaded
 Rear shock absorber (air cham- ber)
 Rear suspension component parts
 Air tube
Revision: 2010 May2011 QX56