2008 INFINITI QX56 Electrical

PCS
PCS-1
ELECTRICAL & POWER CONTROL
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SECTION PCS
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CONTENTS
POWER CONTROL SYSTEM
IPDM E/R
BASIC INSPECTION ....... .............................
2
DIAGNOSIS AND REPAIR WORKFLOW ..... .....2
Work Flow ........................................................... ......2
FUNCTION DIAGNOSIS ...............................5
RELAY CONTROL SYSTEM ......................... .....5
System Diagram .................................................. ......5
System Description ...................................................6
Component Parts Location ........................................7
POWER CONTROL SYSTEM .............................8
System Diagram .................................................. ......8
System Description ...................................................8
SIGNAL BUFFER SYSTEM ................................9
System Diagram .................................................. ......9
System Description ...................................................9
POWER CONSUMPTION CONTROL SYS-
TEM ....................................................................
10
System Diagram .................................................. ....10
System Description .................................................10
Component Parts Location ......................................11
DIAGNOSIS SYSTEM (IPDM E/R) .....................12
Diagnosis Description ......................................... ....12
CONSULT - III Function (IPDM E/R) .......................14
COMPONENT DIAGNOSIS .........................17
U1000 CAN COMM CIRCUIT ...........................17
Description ........................................................... ....17
DTC Logic ................................................................17
Diagnosis Procedure ...............................................17
POWER SUPPLY AND GROUND CIRCUIT ....18
Diagnosis Procedure ...............................................18
ECU DIAGNOSIS .........................................19
IPDM E/R (INTELLIGENT POWER DISTRI-
BUTION MODULE ENGINE ROOM) ................
19
Reference Value .................................................. ....19
Terminal Layout .......................................................21
Physical Values ................................................... ....21
Wiring Diagram ........................................................26
Fail Safe ..................................................................29
DTC Index ...............................................................31
PRECAUTION ..............................................32
PRECAUTIONS .................................................32
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ....
32
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect ...................................
32
REMOVAL AND INSTALLATION ...............34
IPDM E/R (INTELLIGENT POWER DISTRI-
BUTION MODULE ENGINE ROOM) ................
34
Removal and Installation of IPDM E/R ................ ....34
Revision: March 2010 2008 QX56

PCS-32
< PRECAUTION >[IPDM E/R]
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint Syst
em (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004857510
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 severity 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 inopera tive, 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 unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harn esses can be identified 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 Unit or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or electri c 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:0000000004857511
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 disconnecting 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 pow er 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

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PG-1
ELECTRICAL & POWER CONTROL
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SECTION PG
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CONTENTS
POWER SUPPLY, GROUND & CIRCUIT ELEMENTS
PRECAUTION .......
........................................2
PRECAUTIONS .............................................. .....2
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
2
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect ............................... ......
2
Precaution for Power Generation Variable Voltage
Control System ..........................................................
3
PREPARATION ............................................4
PREPARATION .............................................. .....4
Special Service Tool ........................................... ......4
Commercial Service Tool ..........................................4
BASIC INSPECTION ....................................5
BATTERY ....................................................... .....5
How to Handle Battery ........................................ ......5
Work Flow ........................................................... ......7
INSPECTION AND ADJUSTMENT .....................8
ADDITIONAL SERVICE WHEN REMOVING BAT-
TERY NEGATIVE TERMINAL ............................... ......
8
ADDITIONAL SERVICE WHEN REMOVING
BATTERY NEGATIVE TERMINAL : Special Re-
pair Requirement ................................................. ......
8
COMPONENT DIAGNOSIS ..........................9
POWER SUPPLY ROUTING CIRCUIT .......... .....9
Wiring Diagram — Battery Power Supply — ....... ......9
Wiring Diagram — Accessory Power Supply — .....17
Wiring Diagram — Ignition Power Supply — ....... ....21
Fuse .........................................................................29
Fusible Link .............................................................29
GROUND ...........................................................30
Ground Distribution ..................................................30
HARNESS .........................................................40
Harness Layout ................................................... ....40
ELECTRICAL UNITS LOCATION ....................62
Electrical Units Location ..........................................62
HARNESS CONNECTOR .................................65
Description ...............................................................65
STANDARDIZED RELAY .................................68
Description ...............................................................68
FUSE BLOCK - JUNCTION BOX (J/B) ............70
Terminal Arrangement .............................................70
FUSE, FUSIBLE LINK AND RELAY BOX ........71
Terminal Arrangement .............................................71
ON-VEHICLE REPAIR .................................73
BATTERY ..........................................................73
Removal and Installation ..................................... ....73
SERVICE DATA AND SPECIFICATIONS
(SDS) ............... .......................................... ...
74
SERVICE DATA AND SPECIFICATIONS
(SDS) .................................................................
74
Battery ................................................................. ....74
Revision: March 2010 2008 QX56

PG-2
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000004913900
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 severity 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 inopera tive, 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 unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the SR section.
• Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harn esses can be identified 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 Unit or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or electri c 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:0000000004913899
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 disconnecting 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 pow er 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

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PRECAUTIONSPG-3
< PRECAUTION >
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5. When the repair work is completed, return the ignition switch to the
″LOCK ″ position before connecting
the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of al l control units using CONSULT-III.
Precaution for Power Generation Variable Voltage Control SystemINFOID:0000000001538888
CAUTION:
For this model, the battery current sensor that is installed to the negative battery cable measures the
charging/discharging current of the battery and performs various engine controls. If an electrical com-
ponent is connected directly to the negative battery terminal, the current flowing through that compo-
nent will not be measured by the battery current sensor. This condition may cause a malfunction of
the engine control system and battery discharge m ay occur. Do not connect an electrical component
or ground wire directly to the battery terminal.
Revision: March 2010 2008 QX56

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POWER SUPPLY ROUTING CIRCUITPG-29
< COMPONENT DIAGNOSIS >
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FuseINFOID:0000000001744671
• If fuse is blown, be sure to eliminate cause of malfunction before
installing new fuse.
• Use fuse of specified rating. Never use fuse of more than specified
rating.
• Do not partially install fuse; always insert it into fuse holder prop- erly.
• Remove fuse for “ELECTRICAL PARTS (BAT)” if vehicle is not used for a long period of time.
Fusible LinkINFOID:0000000001744672
A melted fusible link can be detected either by visual inspection or by
feeling with finger tip. If its condition is questionable, use circuit
tester or test lamp.
CAUTION:
• If fusible link should melt, it is possible that critical circuit
(power supply or large current carrying circuit) is shorted. In
such a case, carefully check and eliminate cause of malfunc-
tion.
• Never wrap outside of fusible li nk with vinyl tape. Important:
Never let fusible link touch any other wiring harness, vinyl or
rubber parts.
CEL083
1 : Fusible link
ALMIA0015GB
Revision: March 2010 2008 QX56

PG-62
< COMPONENT DIAGNOSIS >
ELECTRICAL UNITS LOCATION
ELECTRICAL UNITS LOCATION
Electrical Units LocationINFOID:0000000001744675
ENGINE COMPARTMENT
ABMIA0164GB
Revision: March 20102008 QX56

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ELECTRICAL UNITS LOCATIONPG-63
< COMPONENT DIAGNOSIS >
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PASSENGER COMPARTMENT
AAMIA0216GB
Revision: March 2010
2008 QX56