Electrical INFINITI QX4 2001 Factory Owners Manual

Trouble Diagnoses Introduction=NBRS0040CAUTION:
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
IDo not attempt to repair, splice or modify the SRS wiring harness. If the harness is damaged,
replace it with a new one.
IKeep ground portion clean.
DIAGNOSIS FUNCTIONNBRS0040S01The SRS self-diagnosis results can be read by using ªAIR BAGº warning lamp and/or CONSULT-II. The read-
ing of these results is accomplished using one of two modes Ð ªUser modeº and ªDiagnosis modeº.
The User mode is exclusively prepared for the customer (driver). This mode warns the driver of a system
malfunction through the operation of the ªAIR BAGº warning lamp.
The Diagnosis mode allows the technician to locate and inspect the malfunctioning part.
The mode applications for the ªAIR BAGº warning lamp and CONSULT-II are as follows:
User mode Diagnosis mode Display type
ªAIR BAGº warning lamp X X ON-OFF operation
CONSULT-II Ð X Monitoring
NOTE:
Seat belt pre-tensioner malfunction is indicated by ªAIR BAGº warning lamp.
DIAGNOSIS MODE FOR CONSULT-IINBRS0040S02IªSELF-DIAG [CURRENT]º
A current Self-diagnosis result (also indicated by the number of warning lamp flashes in the Diagnosis
mode) is displayed on the CONSULT-II screen in real time. This refers to a malfunctioning part requiring
repairs.
IªSELF-DIAG [PAST]º
Diagnosis results previously stored in the memory are displayed on the CONSULT-II screen. The stored
results are not erased until memory erasing is executed.
IªTROUBLE DIAG RECORDº
With TROUBLE DIAG RECORD, diagnosis results previously erased by a reset operation can be displayed
on the CONSULT-II screen.
IªECU DISCRIMINATED NO.º
The diagnosis sensor unit for each vehicle model is assigned with its own, individual classification num-
ber. This number will be displayed on the CONSULT-II screen, as shown below. When replacing the diag-
nosis sensor unit, refer to the part number for the compatibility. After installation, replacement with a cor-
rect unit can be checked by confirming this classification number on the CONSULT-II screen.
SRS851
For INFINITI QX4, the diagnosis sensor unit classification numbers assigned is A540.
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SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
Trouble Diagnoses Introduction
RS-29

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBSC0001The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of side air bag module (located in the outer side of front seat),
satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring harness,
warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
ITo 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 performed
by an authorized INFINITI dealer.
IImproper 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 RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
Wiring Diagrams and Trouble DiagnosisNBSC0002When you read wiring diagrams, refer to the following:
IGI-11, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº for power distribution circuit
When you perform trouble diagnosis, refer to the following:
IGI-35, ªHOW TO FOLLOW TEST GROUP IN TROUBLE DIAGNOSISº
IGI-24, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
SC-2

Trouble Diagnoses with
Battery/Starting/Charging System Tester
NBSC0018CAUTION:
When working with batteries, always wear appropriate eye
protection.
NOTE:
ITo ensure a complete and thorough diagnosis, the battery,
starter and alternator test segments must be done as a set
from start to finish.
IIf battery surface charge is detected while testing, the tester
will prompt you to turn on the headlights to remove the surface
charge.
IIf necessary, the tester will prompt you to determine if the bat-
tery temperature is above or below 0ÉC (32ÉF). Choose the
appropriate selection by pressing the up or down arrow button,
then press ªENTERº to make the selection.
SEL404X
1. Turn off all loads on the vehicle electrical system. Clean or
repair as necessary.
2. Visually inspect the battery, battery terminals and cable ends
with ignition switch in ªOFFº position.
NOTE:
The contact surface between the battery terminals, cable ends and
tester leads must be clean for a valid test. A poor connection will
prevent testing and a ªCHECK CONNECTIONº message will
appear during the test procedures. If this occurs, clean the battery
post and terminals, reconnect them and restart the test.
3. Connect the red tester lead clamp to the positive battery
terminal, and the black to the negative terminal.
SEL405X
4. The tester will turn on automatically. Using the arrow keys,
select ªIN VEHICLEº on the tester and then press the ªENTERº
key.
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BATTERY
Trouble Diagnoses with Battery/Starting/Charging System Tester
SC-7

Trouble Diagnoses with
Battery/Starting/Charging System Tester
NBSC0019NOTE:
To ensure a complete and thorough diagnosis, the battery, starter
and alternator test segments must be done as a set from start to
finish.
SEL408X
1. Turn off all loads on the vehicle electrical system.
2. Perform battery test with Battery/Starting/Charging system
tester. Refer to SC-7.
3. Press ªENTERº to begin the starting system test.
SEL409X
4. Start the engine.
SEL410X
5. Diagnosis result is displayed on the tester. Refer to ªDIAG-
NOSTIC RESULT ITEM CHARTº, SC-13.
NOTE:
IIf the starter performs normally but the engine does not start,
perform engine diagnosis.
IFor intermittent ªNO CRANKº or ªNO STARTER OPERATIONº
incidents, go to DIAGNOSTIC PROCEDURE 2.
STARTING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester
SC-12

System DescriptionNBSC0009The alternator provides DC voltage to operate the vehicle's electrical system and to keep the battery charged.
The voltage output is controlled by the IC regulator.
Power is supplied at all times to alternator terminal S through:
I120A fusible link (lettera, located in the fuse and fusible link box), and
I7.5A fuse (No. 65, located in the fuse and fusible link box).
Terminal B supplies power to charge the battery and operate the vehicle's electrical system. Output voltage
is controlled by the IC regulator at terminal S detecting the input voltage. The charging circuit is protected by
the 120A fusible link.
Terminal E of the alternator supplies ground through body ground E101.
With the ignition switch in the ON or START position, power is supplied
Ithrough 10A fuse [No. 8, located in the fuse block (J/B)]
Ito combination meter terminal 12 for the charge warning lamp.
Ground is supplied to terminal 43 of the combination meter through terminal L of the alternator. With power
and ground supplied, the charge warning lamp will illuminate. When the alternator is providing sufficient volt-
age with the engine running, the ground is opened and the charge warning lamp will go off.
If the charge warning lamp illuminates with the engine running, a fault is indicated.GI
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CHARGING SYSTEM
System Description
SC-19

Trouble Diagnoses with
Battery/Starting/Charging System Tester
NBSC0020NOTE:
To ensure a complete and thorough diagnosis, the battery, starter
and alternator test segments must be done as a set from start to
finish.
SEL417X
1. Turn off all loads on the vehicle electrical system.
2. Perform battery and starting system test with Battery/Starting/
Charging system tester.
3. Press ªENTERº to begin the charging system test.
4. Start engine.
SEL418X
5. Press ªENTERº until ªLOADS OFF REV ENGINE 5 SECº is
displayed.
6. Raise and hold the engine speed at 1,500 to 2,000 rpm for
about 5 seconds, then return to the engine to idle.
Once the increase in engine rpm is detected, press ªENTERº
to continue.
NOTE:
IIf after 30 seconds an increase in engine idle speed is not
detected, ªRPM NOT DETECTEDº will display.
ISome engines may have a higher idle initially after starting,
particularly when the engine is cold. The tester may detect this
without any other action being taken. If this occurs, continue on
with the testing process. The final results will not be affected.
SEL419X
7. The tester now checks the engine at idle and performs the
DIODE/RIPPLE check.
8. When complete, the tester will prompt you to turn on the fol-
lowing electrical loads.
IHeater fun set to highest. Do not run the A/C or windshield
defroster.
IHeadlamp high beam
IRear window defogger
NOTE:
Do not run the windshield wipers or any other cyclical loads.
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CHARGING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester
SC-21

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBST0044The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of side air bag module (located in the outer side of front seat),
satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring harness,
warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
ITo 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 performed
by an authorized INFINITI dealer.
IImproper 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 RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
Precautions for Steering SystemNBST0002IBefore disassembly, thoroughly clean the outside of the unit.
IDisassembly should be done in a clean work area. It is important to prevent the internal parts from
becoming contaminated by dirt or other foreign matter.
IPlace disassembled parts in order, on a parts rack, for easier and proper assembly.
IUse nylon cloths or paper towels to clean the parts; common shop rags can leave lint that might
interfere with their operation.
IBefore inspection or reassembly, carefully clean all parts with a general purpose, non-flammable
solvent.
IBefore assembly, apply a coat of recommended power steering fluid* to hydraulic parts. Vaseline
may be applied to O-rings and seals. Do not use any grease.
IReplace all gaskets, seals and O-rings. Avoid damaging O-rings, seals and gaskets during instal-
lation. Perform functional tests whenever designated.
*: Genuine Nissan PSF II or equivalent. Refer to MA-11, ªFluids and Lubricantsº.
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
ST-2

TRANSFER
SECTION
TF
CONTENTS
PRECAUTIONS...............................................................3
Supplemental Restraint System (SRS)²AIR
BAG²and²SEAT BELT PRE-TENSIONER²...............3
Precautions ..................................................................3
Service Notice..............................................................4
Wiring Diagrams and Trouble Diagnosis .....................4
PREPARATION...............................................................5
Special Service Tools ..................................................5
Commercial Service Tools ...........................................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
Location of Electrical Parts ........................................14
Description of Electrical Parts ...................................15
TRANSFER MOTOR................................................15
WAIT DETECTION SWITCH.....................................15
2-4WD SHIFT SOLENOID VALVE.............................16
LINE PRESSURE SWITCH.......................................16
Circuit Diagram for Quick Pinpoint Check.................17
Wiring Diagram - TF -................................................18
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION...............................................................27
Trouble Diagnosis without CONSULT-II ....................27
DESCRIPTION........................................................27
SELF-DIAGNOSTIC PROCEDURE............................28
INDICATIONS OF 4WD WARNING LAMP..................29
Trouble Diagnosis with CONSULT-II .........................30
SELF-DIAGNOSIS...................................................30
SELF-DIAGNOSTIC ITEMS......................................31
DATA MONITOR......................................................33
DATA MONITOR ITEMS...........................................34
REFERENCE VALUE IN DATA MONITOR MODE......36
WORK SUPPORT....................................................38
CLUTCH FORCE RELEASE LIMIT ADJUSTMENT.....39
TROUBLE DIAGNOSIS - INTRODUCTION..................41Introduction ................................................................41
DESCRIPTION........................................................41
DIAGNOSTIC WORKSHEET.....................................41
Work Flow ..................................................................43
HOW TO PERFORM TROUBLE DIAGNOSES FOR
QUICK AND ACCURATE REPAIR
.............................43
TROUBLE DIAGNOSIS - BASIC INSPECTION...........44
Listen to Customer Complaints .................................44
Transfer Fluid Check .................................................44
Road Test...................................................................44
PREPARATION FOR ROAD TEST............................44
1. CHECK BEFORE ENGINE IS STARTED...............45
2. CHECK AT IDLE..................................................47
3. CRUISE TEST.....................................................51
TROUBLE DIAGNOSIS - GENERAL
DESCRIPTION...............................................................54
Transfer Control Unit Terminals and Reference
Value ..........................................................................54
REMOVAL AND INSTALLATION OF TRANSFER
CONTROL UNIT
......................................................54
INSPECTION OF TRANSFER CONTROL UNIT..........54
TRANSFER CONTROL UNIT INSPECTION TABLE....55
VEHICLE SPEED SENSOR (FRONT
REVOLUTION SENSOR)..............................................61
Diagnostic Procedure ................................................61
4WD SOLENOID VALVE...............................................64
Diagnostic Procedure ................................................64
2-4WD SHIFT SOLENOID VALVE AND 4WD
SHIFT SWITCH..............................................................66
Diagnostic Procedure ................................................66
TRANSFER MOTOR AND TRANSFER MOTOR
RELAY...........................................................................70
Diagnostic Procedure ................................................70
TRANSFER FLUID TEMPERATURE SENSOR............73
Diagnostic Procedure ................................................73
ATP SWITCH, WAIT DETECTION SWITCH AND
NEUTRAL-4LO SWITCH...............................................76
Diagnostic Procedure ................................................76
CLUTCH PRESSURE SWITCH....................................80
Diagnostic Procedure ................................................80
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Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBTF0001The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of side air bag module (located in the outer side of front seat),
satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring harness,
warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRSsection of this Service Manual.
WARNING:
ITo 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 performed
by an authorized INFINITI dealer.
IImproper 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 RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
SEF289H
PrecautionsNBTF0092IBefore 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.
SEF291H
IWhen connecting or disconnecting pin connectors into or
from Transfer control unit, take care not to damage pin
terminals (bend or break).
Make sure that there are not any bends or breaks on
Transfer control unit pin terminal, when connecting pin
connectors.
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PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
TF-3

MEF040DB
IBefore replacing Transfer control unit, perform Transfer
control unit input/output signal inspection and make sure
whether Transfer control unit functions properly or not.
(See page TF-55.)
Service NoticeNBTF00021) 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 inter-
fere 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 procedures,
MA-22, ªChanging All-mode 4WD Transfer Fluidº.
Wiring Diagrams and Trouble DiagnosisNBTF0003When you read wiring diagrams, refer to the following:
IGI-11, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº
When you perform trouble diagnosis, refer to the following:
IGI-35, ªHOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSISº
IGI-24, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
PRECAUTIONS
Precautions (Cont'd)
TF-4