2008 INFINITI QX56 Electrical

BCS
BCS-1
ELECTRICAL & POWER CONTROL
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SECTION BCS
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CONTENTS
BODY CONTROL SYSTEM
BCM
BASIC INSPECTION ....... .............................
3
INSPECTION AND ADJUSTMENT ................ .....3
ADDITIONAL SERVICE WHEN REPLACING
CONTROL UNIT .................................................... ......
3
ADDITIONAL SERVICE WHEN REPLACING
CONTROL UNIT : Description ..................................
3
ADDITIONAL SERVICE WHEN REPLACING
CONTROL UNIT : Special Repair Requirement .......
3
CONFIGURATION ................................................. ......3
CONFIGURATION : Description ...............................3
CONFIGURATION : Special Repair Requirement ......4
FUNCTION DIAGNOSIS .. .............................5
BODY CONTROL SYSTEM ........................... .....5
System Description ............................................. ......5
Component Parts Location ........................................6
COMBINATION SWITCH READING SYSTEM
.....
7
System Diagram .................................................. ......7
System Description ...................................................7
Component Parts Location ......................................10
SIGNAL BUFFER SYSTEM ...............................12
System Diagram .................................................. ....12
System Description .................................................12
POWER CONSUMPTION CONTROL SYS-
TEM ....................................................................
13
System Diagram .................................................. ....13
System Description .................................................13
Component Parts Location ......................................15
DIAGNOSIS SYSTEM (BCM) ............................16
COMMON ITEM ..................................................... ....16
COMMON ITEM : CONSULT-III Function (BCM -
COMMON ITEM) .....................................................
16
BCM ....................................................................... ....16
BCM : CONSULT-III Function (BCM - BCM) ...........16
DOOR LOCK .......................................................... ....17
DOOR LOCK : CONSULT-III Function (BCM -
DOOR LOCK) ..........................................................
17
REAR WINDOW DEFOGGER ............................... ....17
REAR WINDOW DEFOGGER : CONSULT-III
Function (BCM - REAR DEFOGGER) .....................
17
BUZZER ................................................................. ....18
BUZZER : CONSULT-III Function (BCM - BUZZ-
ER) ..........................................................................
18
INT LAMP ............................................................... ....18
INT LAMP : CONSULT-III Function (BCM - INT
LAMP) ......................................................................
18
MULTIREMOTE ENT ............................................. ....19
MULTIREMOTE ENT : CONSULT-III Function
(BCM - MULTIREMOTE ENT) .................................
19
HEADLAMP ........................................................... ....21
HEADLAMP : CONSULT-III Function (BCM -
HEAD LAMP) ...........................................................
21
WIPER .................................................................... ....22
WIPER : CONSULT-III Function (BCM - WIPER) ....22
FLASHER ............................................................... ....23
FLASHER : CONSULT-III Function (BCM -
FLASHER) ...............................................................
23
AIR CONDITIONER ............................................... ....23
AIR CONDITIONER : CONSULT-III Function
(BCM - AUTO AIR CONDITIONER) ........................
23
INTELLIGENT KEY ................................................ ....24
INTELLIGENT KEY : CONSULT-III Function
(BCM - INTELLIGENT KEY) ....................................
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Revision: March 2010 2008 QX56

BCS
BODY CONTROL SYSTEMBCS-5
< FUNCTION DIAGNOSIS > [BCM]
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FUNCTION DIAGNOSIS
BODY CONTROL SYSTEM
System DescriptionINFOID:0000000001696402
OUTLINE
• BCM (Body Control Module) controls the various electrical components. It inputs the information required to
the control from CAN communication and the signal received from each switch and sensor.
• BCM has combination switch reading function for reading the operation status of combination switches (light,
turn signal, wiper and washer) in addition to a function fo r controlling the operation of various electrical com-
ponents. It also has the signal transmission function as the passed point of signal and the power consump-
tion control function that reduces the power consumption with the ignition switch OFF.
• BCM is equipped with the diagnosis function that perfo rms the diagnosis with CONSULT-III and various set-
tings.
BCM control function list
System Refer to
Combination switch reading system BCS-7, "
System Diagram"
Signal buffer systemBCS-12, "System Diagram"
Power consumption control systemBCS-13, "System Diagram"
Auto light systemEXL-11, "System Diagram"
Turn signal and hazard warning lamp systemEXL-16, "System Diagram"
Headlamp systemEXL-7, "System Diagram"
Front fog lamp systemEXL-15, "System Diagram"
Daytime running light systemEXL-9, "System Diagram"
Interior room lamp control systemINL-6, "System Diagram"
Step lamp systemINL-6, "System Diagram"
Interior room lamp battery saver systemINL-13, "BATTERY SAVER : CONSULT-III Function"
Front wiper and washer systemWW-4, "System Diagram"
Rear wiper and washer systemWW-8, "System Diagram"
Warning chime systemWCS-4, "WARNING CHIME SYSTEM : System Diagram"
Door lock system DLK-10, "DOOR LOCK AND UNLOCK SWITCH : System Diagram"
(NATS) Nissan anti-theft systemSEC-13, "System Diagram"
Vehicle security systemSEC-17, "System Diagram"
Rear window defogger systemDEF-4, "System Diagram"
Intelligent Key systemSEC-9, "System Diagram"
Power window systemPWC-5, "SystemDiagram"
RAP (retained accessory power) systemBCS-26, "RETAINED PWR : CONSULT-III Function (BCM - RETAINED
PWR)"
TPMS (tire pressure monitoring system)
BCS-28, "AIR PRESSURE MONITOR : CONSULT-III Function"
Revision: March 2010 2008 QX56

BCS
PRECAUTIONSBCS-53
< PRECAUTION > [BCM]
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental
Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004857558
The Supplemental Restraint System such as “AIR 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 SR and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag 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 SR section.
• 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 Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric 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 Necessary for Steering Wheel Rotation After Battery Disconnect
INFOID:0000000004857559
NOTE:
• This Procedure is applied only to models with Intelligent Key system and NATS (NISSAN ANTI-THEFT SYS-
TEM).
• Remove and install all control units after disconnecti ng both battery cables with the ignition knob in the
″ LOCK ″ position.
• Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If DTC is detected, perform trouble diagnosis according to self-diagnostic results.
For models equipped with the Intelligent Key system and NATS , an electrically controlled steering lock mech-
anism is adopted on the key cylinder.
For this reason, if the battery is disconnected or if the battery is discharged, the steering wheel will lock and
steering wheel rotation will become impossible.
If steering wheel rotation is required when battery power is interrupted, follow the procedure below before
starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Use the Intelligent Key or mechanical key to turn the ignition switch to the ″ACC ″ position. At this time, the
steering lock will be released.
3. Disconnect both battery cables. The steering lock will remain released and the steering wheel can be
rotated.
4. Perform the necessary repair operation.
Revision: March 2010 2008 QX56

PRECAUTIONSBR-3
< PRECAUTION >
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PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004894476
The Supplemental Restraint System such as “AIR 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 SR and SB section of this Service Man-
ual.
WARNING:
• To avoid rendering the SRS inoper ative, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag 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 SR section.
• 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 Airbag Diagnosis Sensor Un it or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or el ectric 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 Necessary for Steering Wheel Rotation After Battery Disconnect
INFOID:0000000004894475
NOTE:
• This Procedure is applied only to models with Intelligent Key system and NATS (NISSAN ANTI-THEFT SYS-
TEM).
• Remove and install all control units after disconnecti ng both battery cables with the ignition knob in the
″ LOCK ″ position.
• Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If DTC is detected, perform trouble diagnosis according to self-diagnostic results.
For models equipped with the Intelligent Key system and NATS , an electrically controlled steering lock mech-
anism is adopted on the key cylinder.
For this reason, if the battery is disconnected or if the battery is discharged, the steering wheel will lock and
steering wheel rotation will become impossible.
If steering wheel rotation is required when battery power is interrupted, follow the procedure below before
starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Use the Intelligent Key or mechanical key to turn the ignition switch to the ″ACC ″ position. At this time, the
steering lock will be released.
3. Disconnect both battery cables. The steering lock will remain released and the steering wheel can be
rotated.
4. Perform the necessary repair operation.
Revision: March 2010 2008 QX56

BRC-12
< FUNCTION DIAGNOSIS >[VDC/TCS/ABS]
VDC
Hydraulic Circuit Diagram
INFOID:0000000005875001
System DescriptionINFOID:0000000001686240
• Vehicle Dynamics Control system detects driver ′s steering operation amount and brake pedal travel from
steering angle sensor and pressure sensors. Using information from yaw rate/side/decel G sensor and
wheel sensor, VDC judges driving condition (conditions of under steer and over steer) to improve vehicle
driving stability by controlling brake application to 4 wheels and engine output.
• During VDC operation, it inform s driver of system operation by flashing SLIP indicator lamp.
• Electrical system diagnosis by CONSULT-III is available.
WFIA0187E
Revision: March 2010 2008 QX56

TCS
BRC-15
< FUNCTION DIAGNOSIS > [VDC/TCS/ABS]
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TCS
System DiagramINFOID:0000000001691092
System DescriptionINFOID:0000000001686244
• Traction Control System is a function that electronically controls engine torque, brake fluid pressure and A/T gear position to ensure the optimum slippage ratio at drive wheels by computing wheel speed signals from 4
wheel sensors. When ABS actuator and electric unit (control unit) detects a spin at drive wheels (rear
wheels), it compares wheel speed signals from all 4 wheel s. At this time, LH and RH rear brake fluid pres-
sure are controlled, while fuel being cut to engine and throttle valve being closed to reduce engine torque by
the control unit. Further more, throttle position is continuously controlled to ensure the optimum engine
torque at all times.
• During TCS operation, it inform s driver of system operation by flashing SLIP indicator lamp.
• Electrical system diagnosis by CONSULT-III is available.
AWFIA0065GB
Revision: March 2010 2008 QX56

BRC-18
< FUNCTION DIAGNOSIS >[VDC/TCS/ABS]
ABS
ABS
System DiagramINFOID:0000000001686247
System DescriptionINFOID:0000000001686248
• Anti-Lock Braking System is a function that detects
wheel revolution while braking, electronically controls
braking force, and prevents wheel locking during s udden braking. It improves handling stability and maneu-
verability for avoiding obstacles.
• Electrical system diagnosis by CONSULT-III is available.
AWFIA0014GB
Revision: March 2010 2008 QX56

EBD
BRC-21
< FUNCTION DIAGNOSIS > [VDC/TCS/ABS]
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EBD
System DiagramINFOID:0000000001691096
System DescriptionINFOID:0000000001686252
• Electric Brake force Distribution is a following functi on. ABS actuator and electric unit (control unit) detects
subtle slippages between the front and rear wheels during braking. Then it electronically controls the rear
braking force (brake fluid pressure) to reduce rear wheel slippage. Accordingly, it improves vehicle stability.
• Electrical system diagnosis by CONSULT-III is available.
AWFIA0014GB
Revision: March 2010 2008 QX56