2011 INFINITI QX56 engine

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
< DTC/CIRCUIT DIAGNOSIS > [AIR LEVELIZER CONTROL SYSTEM]
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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

U1000 CAN COMM CIRCUITSCS-87
< DTC/CIRCUIT DIAGNOSIS > [AIR LEVELIZER CONTROL SYSTEM]
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U1000 CAN COMM CIRCUIT
DescriptionINFOID:0000000006256082
CAN (Controller Area Network) is a serial communication line for real-time application. It is an on-vehicle mul-
tiplex communication line with high data communica tion speed and excellent malfunction detection ability.
Many electronic control units are equipped onto a vehicl e, and each control unit shares information and links
with other control units during operation (not independently ). In CAN communication, control units are con-
nected with 2 communication lines (CAN-H line, CAN-L li ne) allowing a high rate of information transmission
with less wiring. Each control unit transmits/recei ves data but selectively reads required data only.
DTC LogicINFOID:0000000006256083
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” is previously c onducted, always turn ignition switch OFF and wait at
least 10 seconds before performing the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Start the engine.
2. Run engine for at least 2 cons ecutive seconds at idle speed.
3. Perform “Self Diagnostic Results” in “E-SUS”.
Is
“U1000” detected?
YES >> Go to SCS-87, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256084
Go to LAN-18, "Trouble Diagnosis Flow Chart".
DTC Display itemI Malfunction detected condition Possible cause
U1000 CAN COMM CIRCUIT Air levelizer control module is not transmitting or re-
ceiving CAN communication signal for 2 seconds or
more.  Harness or connectors
(CAN communication line is open or
shorted.)
 Air levelizer control module
Revision: 2010 May2011 QX56

SCS-88
< DTC/CIRCUIT DIAGNOSIS >[AIR LEVELIZER CONTROL SYSTEM]
U1010 CONTROL UNIT (CAN)
U1010 CONTROL UNIT (CAN)
DescriptionINFOID:0000000006256085
CAN (Controller Area Network) is a serial communication
line for real-time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent malfunction detection ability.
Many electronic control units are equipped onto a vehi cle, and each control unit shares information and links
with other control units during operation (not independently ). In CAN communication, control units are con-
nected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission
with less wiring. Each control unit transmits/recei ves data but selectively reads required data only.
DTC LogicINFOID:0000000006256086
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
If “DTC CONFIRMATION PROCEDURE” is previously c onducted, always turn ignition switch OFF and wait at
least 10 seconds before performing the next test.
>> GO TO 2.
2.CHECK DTC DETECTION
With CONSULT-III
1. Start the engine.
2. Run engine for at least 2 consecutive seconds at idle speed.
3. Perform “Self Diagnostic Results” in “E-SUS”.
Is
“U1010” detected?
YES >> Go to SCS-88, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006256087
1.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> Replace the air levelizer control module. Refer to SCS-94, "Removal and Installation".
NO >> Repair or replace damaged parts.
DTC Display itemI Malfunction detected condition Possible cause
U1010 CONTROL UNIT (CAN) Detecting error during the initial diagnosis of
CAN controller of air le
velizer control module. Air levelizer control module
Revision: 2010 May2011 QX56