2004 INFINITI QX56 Electric

PRECAUTIONS
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Revision: August 20072004 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EHS000VY
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 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 whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WA RN ING:

To avoid rendering the SRS inoperative, 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 per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” ServiceEHS000VZ

Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.

Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 min-
utes.
For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt
pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes
have passed.

The air bag diagnosis sensor unit must always be installed with the arrow mark “⇐” pointing toward the
front of the vehicle for proper operation. Also check air bag diagnosis sensor unit for cracks, deformities or
rust before installation and replace as required.

The spiral cable must be aligned with the neutral position since its rotations are limited. Do not attempt to
turn steering wheel or column after removal of steering gear.

Handle air bag module carefully. Always place driver and front passenger air bag modules with the pad
side facing upward and seat mounted front side air bag module standing with the stud bolt side facing
down.

Conduct self-diagnosis to check entire SRS for proper function after replacing any components.

After air bag inflates, the front instrument panel assembly should be replaced if damaged.
Occupant Classification System PrecautionEHS000W0
Replace control unit and passenger front seat cushion as an assembly.
Trouble Diagnosis PrecautionEHS000W1
When you read wiring diagrams, refer to the following:

GI-15, "How to Read Wiring Diagrams" in GI section

PG-4, "POWER SUPPLY ROUTING CIRCUIT" in PG section
When you perform trouble diagnosis, refer to the following:

GI-11, "HOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSES" in GI section

GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident" in GI section
Check for any service bulletins before servicing the vehicle.

SRS-8
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
TROUBLE DIAGNOSISPFP:00004
Trouble Diagnosis IntroductionEHS000WA
CAUTION:

Do not use electrical test equipment on any circuit related to the SRS unless instructed to do so in
this Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harness con-
nectors.

Do not attempt to repair, splice or modify SRS wiring harnesses. If a harness is damaged, replace
it with a new one.

Keep ground connections clean.
DIAGNOSIS FUNCTION
The SRS self-diagnosis results can be read by using “AIR BAG” warning lamp and/or CONSULT-II.
The User mode is exclusively prepared for the customer (driver). This mode warns the driver of a system mal-
function through the operation of the “AIR BAG” warning lamp.
The Diagnosis mode allows the technician to locate and inspect the malfunctioning part.
The mode applications for the “AIR BAG” warning lamp and CONSULT-II are as follows:
HOW TO PERFORM TROUBLE DIAGNOSES FOR QUICK AND ACCURATE REPAIR
A good understanding of the malfunction conditions can make troubleshooting faster and more accurate.
In general, each customer feels differently about a malfunction. It is important to fully understand the symp-
toms or conditions for a customer complaint.
Information From Customer
WHAT - Vehicle model
WHEN - Date, Frequencies
WHERE - Road conditions
HOW - Operating conditions, Symptoms
Preliminary Check
Check that the following parts are in good order.

Battery (Refer to SC-4, "How to Handle Battery" .)

Fuse (Refer to SRS-12, "Wiring Diagram — SRS —" .)

System component-to-harness connections
User mode Diagnosis mode Display type
“AIR BAG” warning lamp X X ON-OFF operation
CONSULT-II — X Monitoring

SRS-50
FRONT PASSENGER AIR BAG MODULE
Revision: August 20072004 QX56
FRONT PASSENGER AIR BAG MODULEPFP:K8515
Removal and InstallationEHS000WN
The passenger air bag module originally installed in the vehicle uses direct-connect style harness connectors.
Service replacement passenger air bag modules use tab-locking style harness connectors. If the passenger
air bag module is replaced or if the direct-connect harness connectors are damaged, the vehicle wiring har-
ness must be modified to allow connection of the service replacement passenger air bag module. Refer to
SRS-51, "
WIRING HARNESS MODIFICATION" for wiring harness modification procedure.
REMOVAL
CAUTION:

Do not attempt to repair or replace damaged direct-connect front passenger air bag module con-
nectors. If a direct-connect harness connector is damaged, the front passenger air bag must be
replaced and the wiring harness modified.

Before servicing SRS, turn the ignition switch off, disconnect both battery cables and wait at least
3 minutes.

Always work from the side of or under front passenger air bag module.
1. Remove the glove box. Refer to IP-10, "
INSTRUMENT PANEL ASSEMBLY" .
2. Remove 2 nuts (through glove box opening) retaining front pas-
senger air bag module to instrument panel crossmember.
3. Disconnect the air bag module electrical connectors.

For removal/installation of the direct-connect SRS connec-
tors, refer to SRS-7, "
Direct-connect SRS Component Con-
nectors" .
4. Remove the instrument panel assembly from the vehicle. Refer
to IP-10, "
INSTRUMENT PANEL ASSEMBLY" .
5. Remove front passenger air bag module nuts and remove air
bag module from the instrument panel assembly.
CAUTION:

When servicing the SRS, do not work from directly in front
of air bag module.

Always place front passenger air bag module with caution
label side facing upward.

Do not insert any foreign objects (screwdriver, etc.) into air
bag module or harness connectors.

Do not disassemble air bag module.

Do not use old nuts after removal; replace with new nuts.

Do not expose the front passenger air bag module to tem-
peratures exceeding 90°C (194°F).

Replace the air bag module if it has been dropped or sus-
tained an impact.

Do not allow oil, grease or water to come in contact with the
air bag module.

For removal/installation of the direct-connect SRS connec-
tors, refer to SRS-7, "
Direct-connect SRS Component Con-
nectors" .
INSTALLATION
Original Passenger Air Bag Module
To install, reverse the removal procedure.
WHIA0110E
W H I A 0111 E
SBF 8 14 E

SRS-52
FRONT PASSENGER AIR BAG MODULE
Revision: August 20072004 QX56
4. Slide a piece of dual-wall heat shrink tubing (provided in the pas-
senger air bag service kit) onto each wire of the previously used
vehicle wiring harness.
5. Fold each wire back and insert into the end of the heat shrink
tubing so that the end of the wire is approximately centered in
the heat shrink tubing.
6. Use a heat gun to shrink the heat shrink tubing and seal the wire.
7. Use electrical tape to secure the modified circuits to the outside of the wiring harness.
8. Locate the front passenger air bag service replacement connec-
tor that is taped back to the main harness. Unwrap the tape to
access the yellow service replacement connector and remove
the dust cover from the connector.
LHIA0017E
WHIA0062E
WHIA0118E

TF-1
TRANSFER
D DRIVELINE/AXLE
CONTENTS
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SECTION TF
A
B
TF
Revision: August 20072004 QX56 PREPARATION ........................................................... 4
Special Service Tools ............................................... 4
Commercial Service Tools ........................................ 7
PRECAUTIONS .......................................................... 8
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 8
Precautions .............................................................. 8
Service Notice .......................................................... 9
Wiring Diagrams and Trouble Diagnosis .................. 9
ALL-MODE 4WD SYSTEM ...................................... 10
Cross-sectional View .............................................. 10
Control System ........................................................11
ALL-MODE 4WD TRANSFER BASIC CONTROL
... 12
HYDRAULIC CONTROL CIRCUITS ................... 12
OUTLINE ............................................................. 12
CONTROL SYSTEM DIAGRAM ......................... 13
INDICATIONS OF 4WD WARNING LAMP ......... 13
CAN Communication .............................................. 13
SYSTEM DESCRIPTION .................................... 13
Location of Electrical Parts ..................................... 14
Description of Electrical Parts ................................ 15
TRANSFER MOTOR .......................................... 15
WAIT DETECTION SWITCH .............................. 15
2-4WD SHIFT SOLENOID VALVE ...................... 15
LINE PRESSURE SWITCH ................................ 16
Circuit Diagram for Quick Pinpoint Check .............. 17
Wiring Diagram — T/F — ....................................... 18
ON BOARD DIAGNOSTIC SYSTEM DESCRIP-
TION .......................................................................... 27
Trouble Diagnosis without CONSULT-II ................. 27
DESCRIPTION .................................................... 27
SELF-DIAGNOSTIC PROCEDURE .................... 28
INDICATIONS OF 4WD WARNING LAMP ......... 28CONSULT-II Function (ALL MODE AWD/4WD) ..... 31
Trouble Diagnosis with CONSULT-II ...................... 31
SELF-DIAGNOSIS .............................................. 31
SELF-DIAGNOSTIC ITEMS ................................ 32
DATA MONITOR ................................................. 34
DATA MONITOR ITEMS ..................................... 35
REFERENCE VALUE IN DATA MONITOR MODE
... 38
WORK SUPPORT ............................................... 41
CLUTCH FORCE RELEASE LIMIT ADJUST-
MENT .................................................................. 42
TROUBLE DIAGNOSIS — INTRODUCTION ........... 44
Introduction ............................................................. 44
DESCRIPTION .................................................... 44
DIAGNOSTIC WORKSHEET .............................. 44
Work Flow ............................................................... 46
HOW TO PERFORM TROUBLE DIAGNOSES
FOR QUICK AND ACCURATE REPAIR ............. 46
TROUBLE DIAGNOSIS — BASIC INSPECTION .... 47
Listen to Customer Complaints .............................. 47
Transfer Fluid Check .............................................. 47
Road Test ............................................................... 47
PREPARATION FOR ROAD TEST ..................... 47
1. CHECK BEFORE ENGINE IS STARTED ....... 48
2. CHECK AT IDLE .............................................. 49
3. CRUISE TEST ................................................. 53
TROUBLE DIAGNOSIS — GENERAL DESCRIP-
TION .......................................................................... 55
Transfer Control Unit Terminals and Reference
Value ....................................................................... 55
TRANSFER CONTROL UNIT HARNESS CON-
NECTOR LAYOUT .............................................. 55
TRANSFER CONTROL UNIT INSPECTION
TABLE ................................................................. 55
DTC U1000, U1001 CAN COMMUNICATION LINE ... 59
CAN Communication System Inspection ................ 59
4WD SOLENOID VALVE .......................................... 60
Diagnostic Procedure ............................................. 60
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT

TF-8
PRECAUTIONS
Revision: August 20072004 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EDS0017J
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 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 whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WAR NIN G:

To avoid rendering the SRS inoperative, 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 per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
PrecautionsEDS0017K

Before connecting or disconnecting the transfer control
unit harness connector, turn ignition switch OFF and dis-
connect negative battery terminal. Failure to do so may
damage the transfer control unit. Because battery voltage is
applied to transfer control unit even if ignition switch is
turned off.

When connecting or disconnecting pin connectors into or
from transfer control unit, take care not to damage pin ter-
minals (bend or break).
Make sure that there are not any bends or breaks on trans-
fer control unit pin terminal, when connecting pin connec-
tors.

Before replacing transfer control unit, perform transfer con-
trol unit input/output signal inspection and make sure
whether transfer control unit functions properly or not. (See
page TF-55
.)
SEF 2 89 H
SEF 2 91 H
MEF040DB

PRECAUTIONS
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Revision: August 20072004 QX56
Service NoticeEDS0017L
1. Before proceeding with disassembly, thoroughly clean the outside of the all-mode 4WD transfer. It is
important to prevent the internal parts from becoming contaminated by dirt or other foreign matter.
2. Disassembly should be done in a clean work area.
3. Use lint-free cloth or towels for wiping parts clean. Common shop rags can leave fibers that could interfere
with the operation of the all-mode 4WD transfer.
4. Place disassembled parts in order for easier and proper assembly.
5. All parts should be carefully cleaned with a general purpose, non-flammable solvent before inspection or
reassembly.
6. Gaskets, seals and O-rings should be replaced any time the all-mode 4WD transfer is disassembled.
7. It is very important to perform functional tests whenever they are indicated.
8. The valve body contains precision parts and requires extreme care when parts are removed and serviced.
Place removed parts in a parts rack in order to replace them in correct positions and sequences. Care will
also prevent springs and small parts from becoming scattered or lost.
9. Properly installed valves, sleeves, plugs, etc. will slide along bores in valve body under their own weight.
10. Before assembly, apply a coat of recommended ATF to all parts. Apply petroleum jelly to protect O-rings
and seals, and to hold bearings and washers in place during assembly. Do not use grease.
11. Extreme care should be taken to avoid damage to O-rings, seals and gaskets when assembling.
12. After overhaul, refill the transfer with new ATF.
13. When the all-mode 4WD transfer drain plug is removed, only some of the fluid is drained. Old all-mode
4WD transfer fluid will remain in torque converter and ATF cooling system. Always follow the proper pro-
cedure. Refer to MA-24, "
Changing Transfer Fluid" .
Wiring Diagrams and Trouble DiagnosisEDS001CE
When you read wiring diagrams, refer to the following:

GI-15, "How to Read Wiring Diagrams" .

PG-4, "POWER SUPPLY ROUTING CIRCUIT" for power distribution circuit.
When you perform trouble diagnosis, refer to the following:

GI-11, "HOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSES".

GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident".

TF-14
ALL-MODE 4WD SYSTEM
Revision: August 20072004 QX56
Location of Electrical PartsEDS0017Q
WDIA0069E