2004 INFINITI QX56 Air

COLLISION DIAGNOSIS
SRS-61
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SRS
Revision: August 20072004 QX56
For Side CollisionEHS0 00 W X
Check the SRS components using the following table.

After the work is completed, perform self-diagnosis to check that no malfunction is detected. Refer to
SRS-20, "
SRS Operation Check" .
WHEN SRS IS ACTIVATED IN THE SIDE COLLISION
1. Replace the following components:
–Front seat back assembly (on the side on which side air bag is activated)
–Diagnosis sensor unit
–(LH or RH) side air bag (satellite) sensor (on the side on which side air bag is activated)
2. Check the SRS components and the related parts using the following table.
–Replace any SRS components and the related parts showing visible signs of damage (dents, cracks,
deformation).
3. Conduct self-diagnosis using CONSULT-II and “AIR BAG” warning lamp. Refer to SRS-20, "
SRS Opera-
tion Check" for details. Ensure entire SRS operates properly.
WHEN SRS IS NOT ACTIVATED IN THE SIDE COLLISION
1. Check the SRS components and the related parts using the following table.
–If the front seat back assembly is damaged, the front seat back assembly must be replaced.
2. Conduct self-diagnosis using CONSULT-II and “AIR BAG” warning lamp. Refer to SRS-20, "
SRS Opera-
tion Check" for details. Ensure entire SRS operates properly.
SRS INSPECTION (FOR SIDE COLLISION)
Harness and connec-
tors1. Check connectors for poor connection, damage, and terminals for deformities.
2. Check harness for binding, chafing, cuts, or deformities.
3. If no damage is found, reinstall the harness and connectors.
4. If damaged—REPLACE the damaged harness. Do not attempt to repair, splice or modify any SRS harness.
Instrument panel
REPLACE the instru-
ment panel assembly.1. Visually check instrument panel for damage.
2. If no damage is found, reinstall the instrument panel.
3. If damaged—REPLACE the instrument panel. Part SRS is activated SRS is NOT activated
Part SRS is activated SRS is NOT activated
(LH or RH) side cur-
tain air bag moduleReplace the side cur-
tain air bag module.
(Repair the center pil-
lar inner, etc. before
installing new one if
damaged.)1. Check for visible signs of damage (dents, tears, deformation) of the center pillar on
the collision side.
2. If damaged—Remove the side curtain air bag module.
3. Check for visible signs of damaged (tears etc.) of the side curtain air bag module.
4. Check harness and connectors for damage, and terminals for deformities.
5. If no damage is found, reinstall the side curtain air bag module with new fasteners.
6. If damaged—REPLACE the side curtain air bag module with new fasteners.
Front (LH or RH) side
air bag moduleREPLACE front seat-
back assembly.1. Check for visible signs of damage (dents, tears, deformation) of the seat back on
the collision side.
2. Check harness and connectors for damage, and terminals for deformities.
3. If damaged—REPLACE the front seatback assembly.
(LH or RH) side air
bag (satellite) sensor REPLACE the side
air bag (satellite) sen-
sor on the collision
side with new fasten-
ers.
(Repair the center pil-
lar inner, etc. before
installing new one if
damaged.)1. Remove the side air bag (satellite) sensor on the collision side. Check harness
connectors for damage, terminals for deformities, and harness for binding.
2. Check for visible signs of damage (dents, cracks, deformation) of the side air bag
(satellite) sensor.
3. Install the side air bag (satellite) sensor to check fit.
4. If no damage is found, reinstall the side sir bag (satellite) sensor with new fasten-
ers.
5. If damaged—REPLACE the side air bag (satellite) sensor with new fasteners.

SRS-62
COLLISION DIAGNOSIS
Revision: August 20072004 QX56
For RolloverEHS001BC
Check the SRS components using the following table.

After the work is completed, perform self-diagnosis to check that no malfunction is detected. Refer to
SRS-20, "
SRS Operation Check" .
WHEN SRS IS ACTIVATED IN THE ROLLOVER
1. Replace the following components:
–Diagnosis sensor unit
–(LH or RH) side air bag (satellite) sensor (on the side on which side air bag is activated)
2. Check the SRS components and the related parts using the following table.
–Replace any SRS components and the related parts showing visible signs of damage (dents, cracks,
deformation).
3. Conduct self-diagnosis using CONSULT-II and “AIR BAG” warning lamp. Refer to SRS-20, "
SRS Opera-
tion Check" for details. Ensure entire SRS operates properly.
WHEN SRS IS NOT ACTIVATED IN THE ROLLOVER
1. Check the SRS components and the related parts using the following table.
–If the front seat back assembly is damaged, the front seat back assembly must be replaced.
2. Conduct self-diagnosis using CONSULT-II and “AIR BAG” warning lamp. Refer to SRS-20, "
SRS Opera-
tion Check" for details. Ensure entire SRS operates properly.
Diagnosis sensor unit REPLACE the diag-
nosis sensor unit with
new fasteners.1. Check case and bracket for dents, cracks or deformities.
2. Check connectors for damage, and terminals for deformities.
3. If no damage is found, reinstall the diagnosis sensor unit with new fasteners.
4. If damaged—REPLACE the diagnosis sensor unit with new fasteners.
Seat belt pre-ten-
sioner assembly and
seat belt buckle pre-
tensioner assembly1. Check if the seat belt can be extended smoothly.
If the seat belt cannot be extended smoothly,
–Check for deformities of the center pillar inner.
–If the center pillar inner has no damage, REPLACE the seat belt pre-tensioner assembly.
2. Remove the seat belt pre-tensioner assembly and the seat belt buckle pre-tensioner assembly on the colli-
sion side. Check harness cover and connectors for damage, terminals for deformities, and harness for bind-
ing.
3. Check for visible signs of damage (dents, cracks, deformation) of the seat belt pre-tensioner assembly and
the seat belt buckle pre-tensioner assembly.
4. Check seat belt adjuster for damage.
5. If no damage is found, reinstall the seat belt pre-tensioner assembly and the seat belt buckle pre-tensioner
assembly.
6. If damaged—REPLACE the seat belt pre-tensioner assembly or the seat belt buckle pre-tensioner assem-
bly with new fasteners.
Seat (with front side
air bag)REPLACE front seat-
back assembly.1. Visually check the seat on the collision side.
2. Remove the seat on the collision side and check the following for damage and
deformities.
–Harness, connectors and terminals
–Frame and recliner (for front and rear seat), and also adjuster and slides (for front
seat)
3. If no damage is found, reinstall the seat.
4. If damaged—REPLACE the damaged seat parts using new fasteners. If the front
seat back is damaged, the front seat back assembly must be replaced.
Center inner pillar 1. Check the center inner pillar on the collision side for damage (dents, cracks, deformation).
2. If damaged—REPAIR the center inner pillar.
Trim/headlining 1. Check for visible signs of damage (dents, cracks, deformation) of the interior trim on the collision side.
2. If damaged—REPLACE the damaged trim parts. Part SRS is activated SRS is NOT activated

COLLISION DIAGNOSIS
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Revision: August 20072004 QX56
SRS INSPECTION (FOR ROLLOVER)
Part SRS is activated SRS is NOT activated
(LH or RH) side cur-
tain air bag moduleReplace the side cur-
tain air bag module.
(Repair the center pil-
lar inner, etc. before
installing new one if
damaged.)1. Check for visible signs of damage (dents, tears, deformation) of the center pillar on
the collision side.
2. If damaged—Remove the side curtain air bag module.
3. Check for visible signs of damaged (tears etc.) of the side curtain air bag module.
4. Check harness and connectors for damage, and terminals for deformities.
5. If no damage is found, reinstall the side curtain air bag module with new fasteners.
6. If damaged—REPLACE the side curtain air bag module with new fasteners.
Front (LH or RH) side
air bag moduleREPLACE front seat-
back assembly.1. Check for visible signs of damage (dents, tears, deformation) of the seat back on
the collision side.
2. Check harness and connectors for damage, and terminals for deformities.
3. If damaged—REPLACE the front seatback assembly.
(LH or RH) side air
bag (satellite) sensor REPLACE the side
air bag (satellite) sen-
sor on the collision
side with new fasten-
ers.
(Repair the center pil-
lar inner, etc. before
installing new one if
damaged.)1. Remove the side air bag (satellite) sensor on the collision side. Check harness
connectors for damage, terminals for deformities, and harness for binding.
2. Check for visible signs of damage (dents, cracks, deformation) of the side air bag
(satellite) sensor.
3. Install the side air bag (satellite) sensor to check fit.
4. If no damage is found, reinstall the side sir bag (satellite) sensor with new fasten-
ers.
5. If damaged—REPLACE the side air bag (satellite) sensor with new fasteners.
Diagnosis sensor unit REPLACE the diag-
nosis sensor unit with
new fasteners.1. Check case and bracket for dents, cracks or deformities.
2. Check connectors for damage, and terminals for deformities.
3. If no damage is found, reinstall the diagnosis sensor unit with new fasteners.
4. If damaged—REPLACE the diagnosis sensor unit with new fasteners.
Seat belt pre-ten-
sioner assembly and
seat belt buckle pre-
tensioner assembly1. Check if the seat belt can be extended smoothly.
If the seat belt cannot be extended smoothly,
–Check for deformities of the center pillar inner.
–If the center pillar inner has no damage, REPLACE the seat belt pre-tensioner assembly.
2. Remove the seat belt pre-tensioner assembly and the seat belt buckle pre-tensioner assembly on the colli-
sion side. Check harness cover and connectors for damage, terminals for deformities, and harness for bind-
ing.
3. Check for visible signs of damage (dents, cracks, deformation) of the seat belt pre-tensioner assembly and
the seat belt buckle pre-tensioner assembly.
4. Check seat belt adjuster for damage.
5. If no damage is found, reinstall the seat belt pre-tensioner assembly and the seat belt buckle pre-tensioner
assembly.
6. If damaged—REPLACE the seat belt pre-tensioner assembly or the seat belt buckle pre-tensioner assem-
bly with new fasteners.
Seat (with front side
air bag)REPLACE front seat-
back assembly.1. Visually check the seat on the collision side.
2. Remove the seat on the collision side and check the following for damage and
deformities.
–Harness, connectors and terminals
–Frame and recliner (for front and rear seat), and also adjuster and slides (for front
seat)
3. If no damage is found, reinstall the seat.
4. If damaged—REPLACE the damaged seat parts using new fasteners. If the front
seat back is damaged, the front seat back assembly must be replaced.
Center inner pillar 1. Check the center inner pillar on the collision side for damage (dents, cracks, deformation).
2. If damaged—REPAIR the center inner pillar.
Trim/headlining 1. Check for visible signs of damage (dents, cracks, deformation) of the interior trim on the collision side.
2. If damaged—REPLACE the damaged trim parts.

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-2Revision: August 20072004 QX56 SWITCH ..................................................................... 62
Diagnostic Procedure ............................................. 62
TRANSFER MOTOR AND TRANSFER MOTOR
RELAY ....................................................................... 64
Diagnostic Procedure ............................................. 64
TRANSFER FLUID TEMPERATURE SENSOR ....... 66
Diagnostic Procedure ............................................. 66
ATP SWITCH, WAIT DETECTION SWITCH AND
NEUTRAL-4LO SWITCH .......................................... 69
Diagnostic Procedure ............................................. 69
CLUTCH PRESSURE SWITCH ................................ 72
Diagnostic Procedure ............................................. 72
LINE PRESSURE SWITCH ....................................... 74
Diagnostic Procedure ............................................. 74
DATA ERASE/DISPLAY ............................................ 76
Diagnostic Procedure ............................................. 76
SHIFT ACTUATOR ................................................... 77
Diagnostic Procedure ............................................. 77
SHIFT ACTUATOR POSITION SWITCH .................. 80
Diagnostic Procedure ............................................. 80
SHIFT ACTUATOR CIRCUIT .................................... 82
Diagnostic Procedure ............................................. 82
TROUBLE DIAGNOSES FOR SYMPTOMS ............. 85
Symptom 1. 4WD Shift Indicator Lamp Does Not
Turn ON (Although the ignition switch is turned ON,
all the 4WD indicator lamps do not turn ON for 1
second) ................................................................... 85
Symptom 2. 4WD Warning Lamp Does Not Turn ON
(Although the ignition switch is turned ON, the 4WD
warning lamp does not turn ON) ............................. 87
Symptom 3. 4WD Shift Indicator Lamp Does Not
Turn OFF (When 4WD shift switch is set from 4H
to 4LO, all the 4WD shift indicator lamps do not turn
off) ........................................................................... 88
Symptom 4. ATP Warning Lamp Does Not Turn ON
(When 4WD shift switch is set from 4H to 4LO with
the A/T selector lever in P position, the ATP warning
lamp does not turn on) ............................................ 89
Symptom 5. 4LO Indicator Lamp Does Not Turn ON
(When 4WD shift switch is set from 4H to 4LO posi-
tion, 4LO indicator lamp does not turn ON) ............ 90
Symptom 6. 4WD Shift Indicator Lamp Does Not
Indicate “LOCK” (When 4WD shift switch is set to
“4H”, 4WD shift indicator lamp does not indicate
“LOCK”) .................................................................. 91
Symptom 7. 4WD Shift Indicator Lamp Repeats
Flickering (4WD Shift Indicator Lamp Keeps Flick-
ering) ...................................................................... 92
Symptom 8. Tight Corner Braking Symptom (Tight
Corner Braking Symptom Occurs-Hydraulic Sys-
tem Failure) ............................................................ 93
Symptom 9. 4WD System Does Not Operate (The
Vehicle Cannot Be Put Into 4WD Mode-Hydraulic
System Failure) ...................................................... 94
Component Inspection ............................................ 95
4WD SHIFT SWITCH .......................................... 95
2-4WD SHIFT SOLENOID VALVE AND TRANS-
FER FLUID TEMPERATURE SENSOR .............. 95
4WD SOLENOID VALVE, CLUTCH PRESSURE SWITCH AND LINE PRESSURE SWITCH .........95
TRANSFER DROPPING RESISTOR ..................96
ATP SWITCH, NEUTRAL-4LO SWITCH AND
WAIT DETECTION SWITCH ...............................96
TRANSFER MOTOR ...........................................96
TRANSFER MOTOR RELAY ...............................97
TRANSFER SHIFT RELAY (HIGH & LOW) .........97
ACTUATOR AND ACTUATOR POSITION
SWITCH ...............................................................97
TRANSFER CONTROL UNIT ...................................98
Removal and Installation .........................................98
REMOVAL ............................................................98
INSTALLATION ....................................................98
FRONT OIL SEAL .....................................................99
Removal and Installation .........................................99
REMOVAL ............................................................99
INSTALLATION .................................................. 100
REAR OIL SEAL ..................................................... 101
Removal and Installation ....................................... 101
REMOVAL .......................................................... 101
INSTALLATION .................................................. 101
SIDE OIL SEAL ....................................................... 103
Removal and Installation ....................................... 103
REMOVAL .......................................................... 103
INSTALLATION .................................................. 103
TRANSFER CONTROL DEVICE ............................ 104
Removal and Installation ....................................... 104
AIR BREATHER HOSE ........................................... 105
Removal and Installation ....................................... 105
TRANSFER MOTOR ............................................... 106
Removal and Installation ....................................... 106
REMOVAL .......................................................... 106
INSTALLATION ..................................................... 106
TRANSFER OIL FILTER ......................................... 107
Removal and Installation ....................................... 107
REMOVAL .......................................................... 107
INSTALLATION .................................................. 107
REMOVAL AND INSTALLATION ............................ 109
Removal ................................................................ 109
Installation ............................................................. 109
OVERHAUL .............................................................110
Transfer Components ...........................................110
REAR CASE ............................................................112
Disassembly ..........................................................112
CENTER CASE .......................................................113
Disassembly ..........................................................113
FRONT DRIVE SHAFT AND DRIVE CHAIN .....115
MAINSHAFT AND CLUTCH DRUM ..................116
CLUTCH PISTON ..............................................118
CONTROL VALVE .............................................119
MAINSHAFT REAR BEARING .......................... 122
MAIN OIL PUMP ................................................ 122
SUB OIL PUMP ................................................. 123
OIL FILTER ........................................................ 124
FRONT CASE .......................................................... 125
Disassembly .......................................................... 125
SHIFT ROD COMPONENTS ............................. 125
PLANETARY CARRIER, SUN GEAR AND
INTERNAL GEAR .............................................. 127

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

TROUBLE DIAGNOSIS — INTRODUCTION
TF-45
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TF
Revision: August 20072004 QX56
5.❏ Check component. Repair or replace the damaged parts.TF-109
6.❏ Perform final check. Perform road test (1 through 3).TF-47

TF-46
TROUBLE DIAGNOSIS — INTRODUCTION
Revision: August 20072004 QX56
Work FlowEDS0017X
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 problem. It is important to fully understand the symptoms or
conditions for a customer complaint.
Make good use of the two sheets provided, “Information from Customer” (Refer to TF-44
) and “Diagnostic
Worksheet” (Refer to TF-44
), to perform the best troubleshooting possible.
*1:TF-47*2:TF-47*3:TF-47
*4:TF-85 - TF-94*5:TF-60 - TF-82*6:TF-47
WDIA0102E