2004 INFINITI QX56 diagram

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-12
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Wiring Diagram — SRS —EHS000WD
WHWA0179E

TF-1
TRANSFER
D DRIVELINE/AXLE
CONTENTS
C
E
F
G
H
I
J
K
L
M
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

PRECAUTIONS
TF-9
C
E
F
G
H
I
J
K
L
MA
B
TF
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".

ALL-MODE 4WD SYSTEM
TF-13
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
CONTROL SYSTEM DIAGRAM
INDICATIONS OF 4WD WARNING LAMP
*: When 4WD warning lamp is ON, all the 4WD shift indicator lamps turn OFF.
CAN CommunicationEDS0017P
SYSTEM DESCRIPTION
Refer to LAN-5, "CAN COMMUNICATION" .
WDIA0075E
Condition Content 4WD warning lamp
During self-diagnosis Indicates the malfunction position by number of flickers. Flickers at malfunction mode.
Lamp check*Checks the lamp by turning ON during engine starting. After
engine starts, it turns OFF if there are no malfunctions.ON
Malfunction in 4WD system*Turns ON to indicate malfunction. When ignition switch is
turned to “OFF” or the malfunction is corrected, it turns OFF.ON
When vehicle is driven with different
diameters of front and rear tiresFlickers once every 2 seconds.
Turns OFF when ignition switch is “OFF”.Flickers once every 2 sec-
onds.
High fluid temperature in transfer unitWhen fluid temperature is high or fluid temperature sensor cir-
cuit is shorted, it flickers twice every second.
It turns OFF when fluid temperature becomes normal.Flickers twice a second.
Other than above (System is nor-
mal.)Lamp is OFF. OFF

ALL-MODE 4WD SYSTEM
TF-17
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
Circuit Diagram for Quick Pinpoint CheckEDS0017S
WDWA0033E

TF-18
ALL-MODE 4WD SYSTEM
Revision: August 20072004 QX56
Wiring Diagram — T/F —EDS0017T
WDWA0014E

TF-32
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Revision: August 20072004 QX56
6. Touch “SELF-DIAG RESULTS” on SELECT DIAG MODE
screen.
7. Self-diagnostic results are displayed.
SELF-DIAGNOSTIC ITEMS
BCIA0031E
Detected items
(Screen terms for CONSULT-II,
“SELF-DIAG RESULT” mode)Malfunction is detected when... Check items
Revolution sensor (rear)
(VHCL SPEED SEN·RR)

Signal from vehicle speed sensor 1 (installed on A/T) is
not input due to open circuit.

Improper signal is input while driving.Refer to AT- 11 2 , "
DTC P0720
VEHICLE SPEED SENSOR A/T
(REVOLUTION SENSOR)" .
4WD solenoid valve
(DUTY SOLENOID)

Proper voltage is not applied to solenoid valve due to
open or short circuit.Refer to TF-60, "
Diagnostic Proce-
dure" .
2-4WD shift solenoid valve
(2-4WD SOLENOID)Refer to TF-62, "
Diagnostic Proce-
dure" .
Tran s fe r mo to r re lay
(MOTOR RELAY)

Motor does not operate properly due to open or short cir-
cuit in transfer motor or motor relay.Refer to TF-64, "Diagnostic Proce-
dure" .
Transfer fluid temperature sensor
(FLUID TEMP SENSOR)

Signal voltage from fluid temperature sensor is abnor-
mally high (T/F fluid temperature is abnormally low)
while driving.Refer to TF-66, "Diagnostic Proce-
dure" .
Neutral-4LO switch
(N POSI SW TF)

Improper signal is input while driving.Refer to TF-69, "Diagnostic Proce-
dure" .
Clutch pressure
(CLUTCH PRESSURE)

Improper signal is input due to open or short circuit.

Malfunction occurs in clutch pressure hydraulic circuit.(*1) Refer to TF-72, "
Diagnostic
Procedure" .
Line pressure
(LINE PRESSURE)

Improper signal is input due to open or short circuit.

Malfunction occurs in line pressure hydraulic circuit.(*1) Refer to TF-74, "
Diagnostic
Procedure" .
Engine speed signal (Note 1)
(ENGINE SPEED SIG)

Engine speed is abnormally low while driving.Refer to AT- 11 5 , "DTC P0725
ENGINE SPEED SIGNAL" .
Throttle position sensor
(THRTL POSI SEN)

Signal voltage from throttle position sensor is abnormally
high.

Signal voltage from throttle position sensor is abnormally
low when closed throttle position switch is OFF.Refer to EC-351, "
DTC P0605
ECM" .
Transfer control unit (ADC)
C/U (ADC)/THRTL SEN

Power supply voltage for A/D converter system of trans-
fer control unit is malfunctioning.Refer to EC-351, "DTC P0605
ECM" .
Battery voltage (Note 1)
(BATTERY VOLTAGE)

Power supply voltage for transfer control unit is abnor-
mally low while driving.Refer to TF-18, "Wiring Diagram —
T/F —" .
4WD shift switch
(4WD MODE SW)

More than two switch inputs are simultaneously detected
due to short circuit of 4WD shift switch.Refer to TF-62, "Diagnostic Proce-
dure" .
ABS operation signal (Note 4)
(ABS OPER SIGNAL)

When a malfunction signal due to disconnection or
shorting is detected.

When a defect signal is entered from the ABS control
unit.Refer to BRC-54, "
CAN Communi-
cation System Inspection" .
Wait detection switch (Note 2)
(WAIT DETECT SWITCH)

Improper signal is input due to open or short circuit.(*2) Refer to TF-69, "Diagnostic
Procedure" .