2011 INFINITI QX56 BATTERY

PRE-CRASH SEAT BELT CONTROL UNIT (PASSENGER SIDE)
SBC-17
< ECU DIAGNOSIS INFORMATION >
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PRE-CRASH SEAT BELT CONTROL UNIT (PASSENGER SIDE)
Reference ValueINFOID:0000000006237886
TERMINAL LAYOUT
PHYSICAL VALUES
Fail SafeINFOID:0000000006237887
 When a system malfunction is detected, deactivates a part of the system or all functions depending on the
malfunctioning part.
 When the malfunction condition recovers to the norma l condition, the system returns to the normal opera-
tion.
JMHIA0711ZZ
Te r m i n a l N o .
(Wire color) Description
ConditionVa l u e
(Approx.)
+ – Signal name Input/
Output
1
(Y) Ground Power supply Input — Battery voltage
6
(LG/B) Ground Seat belt buckle switch signal Input Seat belt is fastened 0 V
Seat belt is unfastened 5 V
8
(G) Ground Local Communication Line 2 Input/
Output IGN ON 5 V
9
(–) Ground Shield — — —
16
(W) Ground Local Communication Line 1
Input/
Output ——
18
(B) Ground Ground — — 0 V
19
(W) Ground Motor passenger circuit power supply Input — Battery voltage
20
(B) Ground Motor passenger circuit ground — — 0 V
Display contents of CONSULT-III Fail-safe
U0126 STRG ANG SEN SIG Stops the operation in the conditions as per the following.
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
U0428 STRG ANGL CAL Stops the operation in the conditions as per the following.
 When lateral slippage during cornering occurs
 When steering wheel is rotated for emergency
Revision: 2010 May2011 QX56

B2454 SEAT BLT PWR DR CIRCSBC-41
< DTC/CIRCUIT DIAGNOSIS >
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B2454 SEAT BLT PWR DR CIRC
DTC LogicINFOID:0000000006237906
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-41, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006237907
1.CHECK FUSE
1. Turn ignition switch OFF.
2. Check 30 A fuse (No. 83).
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace the blown fuse after repairing the affected circuit if a fuse is blown.
2.CHECK PRE-CRASH SEAT BELT MOTOR POWER SUPPLY
1. Disconnect pre-crash seat belt control unit (driver side) harness connector.
2. Check voltage between pre-crash seat belt control unit (driver side) harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace harness or connector.
3.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC No. Self-diagnosis item DTC De tection Condition Possible causes
B2454 SEAT BLT PWR DR CIRC Seat belt motor (driver
side) power supply cir-
cuit is open or shorted  Harness or connectors
[Pre-crash seat belt control unit (driver
side) circuit is open or shorted]
 Pre-crash seat belt co ntrol unit (driver side)
Pre-crash seat belt control unit (driver side)
GroundVoltage (V)
Connector Terminal Battery voltage
B9 19
Revision: 2010 May2011 QX56

B2456 SEAT BLT PWR ASSBC-43
< DTC/CIRCUIT DIAGNOSIS >
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B2456 SEAT BLT PWR AS
DTC LogicINFOID:0000000006237910
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.SELF-DIAGNOSIS WITH PRE-CRASH SEAT BELT CONTROL UNIT
1. Turn ignition switch ON.
2. Check “Self-diagnostic result” with CONSULT-III.
Is DTC detected?
YES >> Refer to SBC-43, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006237911
1.CHECK FUSE AND FUSIBLE LINK
1. Turn ignition switch OFF.
2. Check 30 A fuse (No.77).
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace the blown fuse after repairing the affected circuit if a fuse is blown.
2.CHECK PRE-CRASH SEAT BELT MOTOR POWER SUPPLY
1. Disconnect pre-crash seat belt contro l unit (passenger side) harness connector.
2. Check voltage between pre-crash seat belt cont rol unit (passenger side) harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace harness between pre-crash seat belt control unit (passenger side) and fuse.
3.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC No. Self-diagnosis item DTC Detection Condition Possible causes
B2456 SEAT BLT PWR AS
CIRC Pre-crash seat belt control unit (passenger side)
power supply circuit is open or shorted  Harness or connectors
[Pre-crash seat belt control unit (pas-
senger side) circuit is open or shorted]
 Pre-crash seat belt control unit (pas-
senger side)
Pre-crash seat belt control unit (passenger side)
GroundVoltage (V)
(Approx.)
Connector Terminal Battery voltage
B231 19
Revision: 2010 May2011 QX56

SBC-52
< DTC/CIRCUIT DIAGNOSIS >
POWER SUPPLY AND GROUND CIRCUIT
POWER SUPPLY AND GROUND CIRCUIT
Diagnosis ProcedureINFOID:0000000006237930
1.CHECK GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect pre-crash seat belt control unit (driver side and passenger side) harness connector.
3. Check continuity between pre-crash seat belt c ontrol unit (driver side and passenger side) harness con-
nector and ground.
Is the measurement value normal?
YES >> GO TO 2.
NO >> Repair or replace harness or connector.
2.CHECK POWER SUPPLY CIRCUIT-I
Check voltage between pre-crash seat belt control unit (driver side and passenger side) harness connector
and ground.
Is the measurement value normal?
YES >> INSPECTION END
NO >> GO TO 3.
3.CHECKPOWER SUPPLY CIRCUIT-II
1. Disconnect fuse block (J/B) harness connector.
2. Check continuity between pre-crash seat belt c ontrol unit (driver side and passenger side) harness con-
nector and fuse block (J/B) harness connector.
3. Check continuity between pre-crash seat belt c ontrol unit (driver side and passenger side) harness con-
nector and ground.
Is the measurement value normal?
YES >> Check 10 A fuse (No. 6).
NO >> Repair or replace harness or connector.
Pre-crash seat belt control unit GroundContinuity
Connector Terminal
B9 (Driver side) 18
Existed
20
B231 (Passenger side) 18
20
Pre-crash seat belt control unit
GroundVo l ta g e
(Approx.)
Connector Terminal
B9 (Driver side) 1 Battery voltage
B231 (Passenger side)
Pre-crash seat belt control unit Fuse block (J/B) Continuity
Connector Terminal Connector Terminal
B9 (Driver side) 1 M2 6B Existed
B231 (Passenger side)
Pre-crash seat belt control unit GroundContinuity
Connector Terminal
B9 (Driver side) 1 Not existed
B231 (Passenger side)
Revision: 2010 May2011 QX56

SEAT BELT WARNING LAMP CIRCUITSBC-57
< DTC/CIRCUIT DIAGNOSIS >
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SEAT BELT WARNING LAMP CIRCUIT
Component Function CheckINFOID:0000000006237937
1.CHECK SEAT BELT WARNI NG LAMP FUNCTION-I
1. Turn ignition switch ON.
2. Check seat belt warning lamp function.
Is the inspection results normal?
YES >> GO TO 2.
NO >> Check combination meter circuit. Refer to MWI-57, "
Work flow".
2.CHECK SEAT BELT WARNING LAMP FUNCTION-II
1. Sits in the passenger seat.
2. Fasten the seat belt (passenger side).
3. Check seat belt warning lamp function.
Is the inspection results normal?
YES >> Seat belt warning lamp circuit is normal.
NO >> Check seat belt warning lamp circuit. Refer to SBC-57, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000006237938
WARNING:
 Before servicing, turn ignition switch OFF, disconnect battery negative terminal and wait at least 3
minutes. (To discharge backup capacitor.)
 Never use unspecified tester or other measuring device.
1.CHECK SEAT BELT ASSEMBLY (PASSENGER SIDE) CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect air bag diagnosis sensor unit harness connec tor and seat belt assembly (passenger side) har-
ness connector.
3. Check continuity between air bag diagnosis sensor unit harness connector and seat belt assembly (pas-
senger side) harness connector.
4. Check continuity between air bag diagnosis sensor unit harness connector and ground.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Replace harness or connector.
2.CHECK SEAT BELT ASSEMBLY (PASSENGER SIDE) CIRCUIT-II
Check continuity between seat belt assemb ly (passenger side) harness connector and ground.
Condition Seat belt warning lamp
Seat belt (driver side) is fastened Not illuminated
Seat belt (driver side) is unfastened Illuminated
Condition Seat belt warning lamp
Seat belt (passenger side) is fastened Not illuminated
Seat belt (passenger side) is unfastened Illuminated
Air bag diagnosis sensor unit Seat belt assembly (passenger side) Continuity
Connector Terminal Connector Terminal
B228 29 B245 3 Existed
Air bag diagnosis sensor unit GroundContinuity
Connector Terminal
B228 29 Not existed
Revision: 2010 May2011 QX56

SCS-1
SUSPENSION
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SECTION SCS
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O PCONTENTS
SUSPENSION CONTROL SYSTEM
HBMC
PRECAUTION ................ ...............................
4
PRECAUTIONS .............................................. .....4
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
4
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect .....................................
4
Precaution for Procedure without Cowl Top Cover ......5
Precaution for Hydraulic Body-Motion Control
System ......................................................................
5
PREPARATION ............................................6
PREPARATION .............................................. .....6
Special Service Tools .......................................... ......6
Commercial Service Tools ........................................6
SYSTEM DESCRIPTION ..............................7
DESCRIPTION ............................................... .....7
Description .......................................................... ......7
COMPONENT PARTS ........................................8
Component Parts Location .................................. ......8
Component Description .............................................8
STRUCTURE AND OPERATION ........................9
Hydraulic Body-Motion Control System .............. ......9
Shock Absorber .........................................................9
PPMU ......................................................................10
Accumulator ............................................................11
PPMU Pipe ..............................................................11
SYSTEM .............................................................12
System Diagram .................................................. ....12
System Description .................................................12
Component Description ...........................................14
BASIC INSPECTION ...................................15
CHECK SYSTEM PRESSURE .........................15
Work Procedure ................................................... ....15
PRESSURE REDUCING METHOD ..................17
Work Procedure .......................................................17
AIR BLEEDING METHOD ................................18
Work Procedure .......................................................18
CHECK INTERNAL LEAKAGE ........................20
Work Procedure .......................................................20
CHECK FOR MALFUNCTION ..........................22
Work Procedure .......................................................22
CHECK SHOCK ABSORBER FOR MAL-
FUNCTION ....................................... .................
24
Work Procedure ................................................... ....24
CHECK ORIFICE FOR CLOGGING .................27
Work Procedure .......................................................27
SYMPTOM DIAGNOSIS ..............................29
DIFFERENCE IN APPEARANCE .....................29
Description ........................................................... ....29
Inspection Procedure ...............................................29
LARGE ROLL ANGLE ......................................30
Description ...............................................................30
Inspection Procedure ...............................................30
REMOVAL AND INSTALLATION ...............31
HYDRAULIC BODY-MOTION CONTROL
SYSTEM ............................................................
31
Hydraulic Piping ................................................... ....31
FRONT TUBE ASSEMBLY .......................................31
FRONT TUBE ASSEMBLY : Exploded View ...... ....32
FRONT TUBE ASSEMBLY : Removal and Instal-
lation ........................................................................
32
FRONT TUBE ASSEMBLY : Inspection ..................34
Revision: 2010 May2011 QX56

SCS-2
ACCUMULATOR ......................................................34
ACCUMULATOR : Exploded View .........................35
ACCUMULATOR : Removal and Installation ..........35
ACCUMULATOR : Inspection ................................38
ACCUMULATOR : Disposal ...................................38
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE ...38
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Exploded View ......................................................
39
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Removal and Installation ......................................
39
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Inspection .............................................................
43
PPMU, MIDDLE TUBE ASSEMBLY, PPMU PIPE
: Disposal ................................................................
43
REAR TUBE ASSEMBLY ...................................... ...43
REAR TUBE ASSEMBLY : Exploded View ............44
REAR TUBE ASSEMBLY : Removal and Installa-
tion ....................................................................... ...
44
REAR TUBE ASSEMBLY : Inspection ...................46
AIR LEVELIZER CONTROL SYSTEM
PRECAUTION ....... ....................... ...............
47
PRECAUTIONS .............................................. ...47
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" .............................................................. ...
47
Precaution Necessary for Steering Wheel Rota-
tion after Battery Disconnect ..................................
47
Precaution for Procedure without Cowl Top Cover ...48
Precaution for Air Levelizer Control System ...........48
SYSTEM DESCRIPTION ............................49
DESCRIPTION ................................................ ...49
Description ........................................................... ...49
COMPONENT PARTS .......................................50
Component Parts Location .................................. ...50
Component Description ..........................................50
Air Levelizer Control Module ..................................51
Vehicle Height Sensor ............................................51
Air Compressor .......................................................51
Air Compressor Relay ............................................51
CK SUSP Indicator Lamp .......................................51
STRUCTURE AND OPERATION ......................52
Rear Shock Absorber .......................................... ...52
Vehicle Height Sensor ............................................53
SYSTEM .......................................................... ...54
System Diagram .................................................. ...54
System Description .................................................54
Fail-safe ..................................................................55
DIAGNOSIS SYSTEM (AIR LEVELIZER
CONTROL MODULE) ........................................
56
CONSULT-III Function ........................................ ...56
ECU DIAGNOSIS INFORMATION .............58
AIR LEVELIZER CONTROL MODULE .......... ...58
Reference Value .................................................. ...58
Fail-safe ..................................................................59
DTC Inspection Priority Chart .................................59
DTC Index ...............................................................59
WIRING DIAGRAM ....................................61
AIR LEVELIZER CONTROL SYSTEM ........... ...61
Wiring Diagram .................................................... ...61
BASIC INSPECTION ..................................65
DIAGNOSIS AND REPAIR WORKFLOW ...... ...65
Work Flow ............................................................ ...65
Diagnostic Work Sheet ...........................................66
STANDARD VEHICLE HEIGHT SETTING .......67
Description ........................................................... ...67
Work Procedure ......................................................67
DTC/CIRCUIT DIAGNOSIS ........................69
C1801 VHCL HEIGHT SENSOR .................... ...69
DTC Logic ............................................................ ...69
Diagnosis Procedure ..............................................69
Component Inspection ............................................70
C1802 AIR SUS COMPRS RELAY ...................72
DTC Logic ............................................................ ...72
Diagnosis Procedure ..............................................72
C1803 AIR SUSPENSION EXH SOL ................74
DTC Logic ............................................................ ...74
Diagnosis Procedure ..............................................74
Component Inspection ............................................75
C1804 VHCL HEIGHT ADJ UP .........................77
DTC Logic ............................................................ ...77
Diagnosis Procedure ..............................................77
Component Inspection (Air Compressor Relay) .....79
Component Inspection (Air Compressor) ............. ...79
C1805 VHCL HEIGHT ADJ DOWN ...................80
DTC Logic ............................................................ ...80
Diagnosis Procedure ..............................................80
C1806 VHCL HEIGHT SEN FIX ........................81
DTC Logic ............................................................ ...81
Diagnosis Procedure ...............................................81
C1807 VHCL HEIGHT SEN VOLT ....................82
DTC Logic ............................................................ ...82
Diagnosis Procedure ..............................................82
C1808 AIR SUS COMPRS FNCTN ...................84
DTC Logic ............................................................ ...84
Diagnosis Procedure ..............................................84
U1000 CAN COMM CIRCUIT ............................87
Revision: 2010 May2011 QX56

SCS-4
< PRECAUTION >[HBMC]
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint S
ystem (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006256134
The Supplemental Restraint System such as “A IR 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 “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inopera tive, which could increase the risk of personal injury or death in
the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISS AN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipmen t 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 Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the ignition ON or engine running, DO NOT use air or electric 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 minu tes before performing any service.
Precaution Necessary for Steering W heel Rotation after Battery Disconnect
INFOID:0000000006256136
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect bot h battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnos is according to self-diagnosis results.
For vehicle with steering lock unit, if the battery is disconnected or discharged, the steering wheel will lock and
cannot be turned.
If turning the steering wheel is required with the bat tery disconnected or discharged, follow the operation pro-
cedure below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Turn the push-button ignition switch to ACC position. (At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock wi ll remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
Revision: 2010 May2011 QX56