2011 INFINITI QX56 warning

SBC-1
RESTRAINTS
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SECTION SBC
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SBC
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CONTENTS
SEAT BELT CONTROL SYSTEM
PRECAUTION ................ ...............................3
PRECAUTIONS .............................................. .....3
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
3
Precaution for Seat Belt Service ...............................3
SYSTEM DESCRIPTION ..............................5
COMPONENT PARTS ................................... .....5
Component Parts Location .................................. ......5
Component Description .............................................6
SYSTEM ..............................................................7
PRE-CRASH SEAT BELT SYSTEM ...........................7
PRE-CRASH SEAT BELT SYSTEM : System Di-
agram .................................................................. ......
7
PRE-CRASH SEAT BELT SYSTEM : System De-
scription .....................................................................
7
PRE-CRASH SEAT BELT SYSTEM : Fail Safe ........9
SEAT BELT WARNING LAMP SYSTEM ..................10
SEAT BELT WARNING LAMP SYSTEM : System
Diagram ............................................................... ....
10
SEAT BELT WARNING LAMP SYSTEM : System
Description ..............................................................
10
DIAGNOSIS SYSTEM (PRE-CRASH SEAT
BELT) .................................................................
11
CONSULT-III Function ........................................ ....11
ECU DIAGNOSIS INFORMATION ..............13
PRE-CRASH SEAT BELT CONTROL UNIT
(DRIVER SIDE) ............................................... ....
13
Reference Value ................................................. ....13
Fail Safe ..................................................................14
DTC Index ...............................................................16
PRE-CRASH SEAT BELT CONTROL UNIT
(PASSENGER SIDE) ........................................
17
Reference Value .................................................. ....17
Fail Safe ..................................................................17
WIRING DIAGRAM ......................................19
PRE-CRASH SEAT BELT SYSTEM .................19
Wiring Diagram .................................................... ....19
SEAT BELT WARNING SYSTEM ....................26
Wiring Diagram ........................................................26
BASIC INSPECTION ...................................31
DIAGNOSIS AND REPAIR WORKFLOW ........31
Work Flow ............................................................ ....31
DTC/CIRCUIT DIAGNOSIS .........................33
U0126 ST ANG SEN SIG ..................................33
Description ........................................................... ....33
DTC Logic ................................................................33
Diagnosis Procedure ...............................................33
U0428 STRG ANGL CAL ..................................34
Description ...............................................................34
DTC Logic ................................................................34
Diagnosis Procedure ...............................................34
U1000 CAN COMM CIRCUIT ...........................35
Description ...............................................................35
DTC Logic ................................................................35
B2451 SEAT BLT MTR DR CIRC .....................36
DTC Logic ................................................................36
Diagnosis Procedure ...............................................36
B2452 SEAT BLT MTR AS CIRC .....................37
DTC Logic ................................................................37
Diagnosis Procedure ...............................................37
B2453 BR STROKE SEN CIRC ........................38
Revision: 2010 May2011 QX56

SBC-2
DTC Logic ...............................................................38
Diagnosis Procedure ..............................................38
Component Inspection ............................................39
B2454 SEAT BLT PWR DR CIRC .....................41
DTC Logic ............................................................ ...41
Diagnosis Procedure ..............................................41
B2455 CONTROL UNIT DR ..............................42
DTC Logic ............................................................ ...42
Diagnosis Procedure ..............................................42
B2456 SEAT BLT PWR AS ...............................43
DTC Logic ............................................................ ...43
Diagnosis Procedure ..............................................43
B2457 CONTROL UNIT AS ...............................44
DTC Logic ............................................................ ...44
Diagnosis Procedure ..............................................44
B2458 LOCAL COMM .......................................45
DTC Logic ............................................................ ...45
Diagnosis Procedure ..............................................45
B2461 VHCL SPEED SIGNAL ..........................47
Description ........................................................... ...47
DTC Logic ...............................................................47
Diagnosis Procedure ..............................................47
B2463 ROLLOVER SIGNAL .............................48
Description ........................................................... ...48
DTC Logic ...............................................................48
Diagnosis Procedure ..............................................48
B2466 DR/AS CONTROL UNIT ........................49
DTC Logic ............................................................ ...49
Diagnosis Procedure ..............................................49
B2470 SYS HEAT PROTC DR ..........................50
Description ........................................................... ...50
DTC Logic ...............................................................50
Diagnosis Procedure ..............................................50
B2471 SYS HEAT PROTC AS ..........................51
Description ........................................................... ...51
DTC Logic ...............................................................51
Diagnosis Procedure ............................................ ...51
POWER SUPPLY AND GROUND CIRCUIT .....52
Diagnosis Procedure ............................................ ...52
SEAT BELT BUCKLE SWITCH (DRIVER
SIDE) ..................................................................
53
Component Function Check ................................ ...53
Diagnosis Procedure ...............................................53
Component Inspection [Seat Belt Assembly (Driv-
er Side)] ..................................................................
54
SEAT BELT BUCKLE SWITCH (PASSEN-
GER SIDE) .........................................................
55
Component Function Check ................................ ...55
Diagnosis Procedure ...............................................55
Component Inspection [Seat Belt Assembly (Pas-
senger Side)] ...........................................................
56
SEAT BELT WARNING LAMP CIRCUIT ..........57
Component Function Check ................................ ...57
Diagnosis Procedure ...............................................57
Component Inspection [Seat Belt Assembly (Pas-
senger Side)] ...........................................................
58
SYMPTOM DIAGNOSIS ............................60
PRE-CRASH SEAT BELT DOSE NOT OPER-
ATE ................................................................. ...
60
Diagnosis Procedure ............................................ ...60
SEAT BELT WARNING LAMP DOES NOT
TURN OFF .........................................................
61
Diagnosis Procedure ............................................ ...61
SEAT BELT WARNING LAMP DOES NOT
TURN ON ...........................................................
62
Diagnosis Procedure ............................................ ...62
REMOVAL AND INSTALLATION ..............63
BRAKE PEDAL STROKE SENSOR .............. ...63
Exploded View ..................................................... ...63
Removal and Installation .........................................63
Revision: 2010 May2011 QX56

PRECAUTIONSSBC-3
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006237873
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 whether 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 inoper ative, which could increase the risk of personal injury or death in
the event of a collision that would result in air ba g 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 “SRS AIR BAG”.
 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 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 minutes before performing any service.
Precaution for Seat Belt ServiceINFOID:0000000006237874
CAUTION:
 Before removing the seat belt pre-tensioner assembly, turn the ignition switch off, disconnect the
both battery cables and wait at least 3 minutes.
 Do not use electrical test equipment for seat belt pre-tensioner connector.
 After replacing or reinstalling seat belt pre-tens ioner assembly, or reconnecting front seat belt pre-
tensioner connector, check the system function. Refer to SRC-11, "
System Diagram".
 Do not use disassemble buckle or seat belt assembly.
 Replace anchor bolts if th ey are deformed or worn out.
 Never oil tongue and buckle.
 If any component of seat belt assembly is questio nable, do not repair. Replace the whole seat belt
assembly.
 If webbing is cut, frayed, or damaged, replace seat belt assembly.
 When replacing seat belt assembly, u se a genuine NISSAN seat belt assembly.
AFTER A COLLISION
WARNING:
Inspect all seat belt assemblies including retractors and attaching hardware after any collision.
NISSAN recommends that all seat belt assemblies in u se during a collision be replaced unless the col-
lision was minor and the belts show no damage a nd continue to operate properly. Failure to do so
could result in serious personal injury in an accide nt. Seat belt assemblies not in use during a colli-
sion should also be replaced if either damage or im proper operation is noted. Seat belt pre-tensioner
should be replaced even if the seat belts are not in use during a frontal collision in which the air bags
are deployed.
Replace any seat belt assembly (including anchor bolts) if:
Revision: 2010 May2011 QX56

SBC-6
< SYSTEM DESCRIPTION >
COMPONENT PARTS
Component Description
INFOID:0000000006237876
A. View with instrument driver lower cov- er removed B. Combination switch C. View with center pillar lower garnish
removed (driver side)
D. View with center pillar lower garnish re- moved (passenger side)
Component Function
ABS actuator and electric unit (control unit) ABS operation signal is rece
ived from ABS actuator and el ectric unit (control unit)
via CAN communication.
ADAS control unit Intelligent brake assistance operation signal is received from ADAS control unit
via CAN communication.
Air bag diagnosis sensor unit  Detects a collision and supplies power supply for deployment to air bag module
and pre-tensioner seat belt.
 Performs the deploy judgement of passenger air bag based on the information from Occupant Detection System control unit
BCM Ignition ON signal, sleep/wake up signal, and door switch signal are received
from BCM via CAN communication.
Brake pedal stroke sensor  It changes voltage according to brake pedal depressed amount and sends the
signal to pre-crash seat belt control unit.
 There are 2 signals (brake pedal stroke sensor 1 and 2) sent from the brake
pedal stroke sensor. Pre-crash seat belt control unit judges the stroke amount
and the speed of the brake pedal according to the voltage of the signal sent by
each side.
Combination meter  Transmits vehicle speed signal to pre-crash seat belt control unit (driver side).
 Turns the seat belt warning lamp ON when the seat belt is unfastened.
Occupant detection system control unit Judges the passenger seat condition based on the information from occupant de-
tection unit.
Pre-crush seat belt control unit (driver side)  Total control of pre-crash seat belt system is operated according to transmit sig-
nal.
 Driver seat belt retractor integrates pre-crash seat belt control unit (driver side), driver seat belt motor, and tension reducer.
 Seat belt motor operates each operation of pull, return, and hold.
Pre-crush seat belt control unit (passenger side)  Control of passenger pre-crash seat belt is operated according to transmit sig-
nal.
 Passenger seat belt retractor integrates pre-crash seat belt control unit (driver seat), driver seat belt motor, and tension reducer.
 Seat belt motor operates each operation of pull, return, and hold.
Seat belt buckle switch (driver side)  Fastening or not fastening of seat belt is judged. This judgment is used for con-
trol of driver pre-crash seat belt system.
 Seat belt warning lamp on combination meter turns ON when seat belt is not fastened while ignition switch is ON.
 The seat belt buckle switch is installed in the seat belt buckle.
Seat belt buckle switch (passenger side)  Fastening or not fastening of seat belt is judged. This judgment is used to con-
trol passenger pre-crash seat belt system.
 The seat belt buckle switch is installed in the seat belt buckle.
Steering angle sensor Steering angle sensor signal, steering angle speed signal, steering angle sensor
neutral position adjustment completion signal, and steering angle sensor mal-
function signal are received via CAN communication.
Revision: 2010 May2011 QX56

SBC-8
< SYSTEM DESCRIPTION >
SYSTEM
 When the vehicle inclined excessively
 When comfort function operates
OPERATION CONDITION
Operation while driving
 Operation start and stop conditions of pre-crash seat belt system are as shown in the following table.
 The activation and deactivation conditions of pre-crush seat belt are as per the following.
NOTE:
For details of intelligent brake assist system.Refer to BRC-152, "
INTELLIGENT BRAKE ASSIST : System
Description".
Comfort function
 Seat belt is retracted and the looseness is reduced in the state as shown in the following table.
 Operation start and stop conditions of pre-crash seat belt system are as shown in the following table.
Operation Prohibition Condition
Pre-crash seat belt system does not operate in the following conditions.
 When seat belt is not fastened (only the seat belt that is not fastened does not operate)
 When motor is overheat due to contentious operation*1
 When the system is in fail-safe mode *1: System operation is temporarily deactivated to av oid overheating, when comfort function is continuously
operated (18 times or more) during a short period of time by fastening and unfastening seat belts or opening
and closing doors.
MALFUNCTION WARNING
When system malfunction is detected, comfort function is deactivated to warn customer of system malfunc-
tion.
Operation item Operation start condition Operation stop condition
During emergency brake operation  Vehicle speed is 15 km/h (9 MPH) or more
 Emergency braking status is detected
 During acceleration
 When stopped
When ABS continuously operates  ABS continuously operates for 2 seconds or
more
 Brake pedal is in depressed state
When intelligent brake assistance oper-
ates System detects that intelligent brake assistance is
in operating status
2 seconds after operation start
When lateral slippage during cornering
occurs  Vehicle speed is 30 km/h (19 MPH) or more
 System detects that the vehicle is in lateral slip-
page state
 System detects that the vehicle is driving on a curve  Vehicle stopped
 1 second or more after maintaining
steering wheel angle in straight driv-
ing state
When steering wheel is rotated for emer-
gency  Vehicle speed is 60 km/h (36 MPH) or more
 Steering wheel angle is 90 degrees or more
 System detects that steering wheel is rotated for
emergency
When the vehicle inclined excessively  Vehicle speed is 30 km/h (19 MPH) or more
 System detects that the vehicle inclined exces-
sively  During acceleration
 Vehicle stopped
Operation item Activating condition Deactivating condition
Door open  Seat belt is in not fastened state
 Door is operated to open from closed
 Vehicle stopped  Seat belt retract is complete
 13 seconds after start retracting
Seat belt is fastened  When door is closed
 Seat belt is fastened  Seat belt is unfastened
 1 second after operation
Seat belt is release Seat belt is unfastened  Seat belt retract is complete
 10 seconds after start retracting
Revision: 2010 May2011 QX56

SBC-10
< SYSTEM DESCRIPTION >
SYSTEM
SEAT BELT WARNING LAMP SYSTEM
SEAT BELT WARNING LAMP SYSTEM : System DiagramINFOID:0000000006237880
SEAT BELT WARNING LAMP SYSTEM : System DescriptionINFOID:0000000006237881
 Turns ON seat belt warning lamp, when the Occupant Detection System judges adult or child in the front
passenger seat and the passenger seat belt buckle switch is OFF.
 Operation of air bag diagnosis sensor unit when air bag diagnosis sensor unit receives information from
Occupant Detection System.
 In addition, seat belt warning lamp illuminates, when t he driver side seat belt is not fasten. This does not
relate to the air bag diagnosis sensor unit.
 For driver seat belt function, refer to MWI-16, "
MASTER WARNING LAMP : System Diagram"
JMHIA0685GB
Status (front passenger seat) Seat belt warning lamp (When front passenger seat is unbuck-
led)
Empty OFF
An object OFF
Child/ child-seat ON
Adult ON
Malfunction OFF
Zero point reset
Not yet performed (service parts only) OFF
Revision: 2010 May2011 QX56

SBC-26
< WIRING DIAGRAM >
SEAT BELT WARNING SYSTEM
SEAT BELT WARNING SYSTEM
Wiring DiagramINFOID:0000000006237889
JCHWM0721GB
Revision: 2010 May2011 QX56

SEAT BELT WARNING SYSTEMSBC-27
< WIRING DIAGRAM >
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JCHWM0722GB
Revision: 2010 May2011 QX56