2001 INFINITI QX4 Electrical

Precautions
SUPPLEMENTAL RESTRAINT SYSTEM (SRS) ªAIR BAGº AND ªSEAT BELT
PRE-TENSIONERº
NBRS0005The 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 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).
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.
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 SRS ªAIR BAGº AND ªSEAT BELT PRE-TENSIONERº SERVICENBRS0006IDo not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
IBefore servicing the SRS, turn ignition switch ªOFFº, disconnect both battery cables and wait at least 3
minutes.
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.
IDiagnosis sensor unit must always be installed with their arrow marks ªgº pointing towards the front of
the vehicle for proper operation. Also check diagnosis sensor unit for cracks, deformities or rust before
installation and replace as required.
IThe 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.
IHandle air bag module carefully. Always place driver and passenger air bag modules with the pad side
facing upward and side air bag module (built-in type) standing with the stud bolt side setting bottom.
IConduct self-diagnosis to check entire SRS for proper function after replacing any components.
IAfter air bag inflates, the front instrument panel assembly should be replaced if damaged.
WIRING DIAGRAMS AND TROUBLE DIAGNOSISNBRS0007When 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 GROUPS IN TROUBLE DIAGNOSESº
IGI-24, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
Precautions
RS-10

SRS797-A
Maintenance ItemsNBRS0011CAUTION:
Do not use electrical test equipment to check SRS circuit.
1. Check operation of ªAIR BAGº warning lamp.
After turning ignition key to ªONº position, air bag warning lamp
illuminates. The ªAIR BAGº warning lamp will go off after about
7 seconds if no malfunction is detected. If any of the following
warning lamp conditions occur, immediately check the air bag
or seat belt pre-tensioner system. Refer to RS-38 for details.
IThe ªAIR BAGº warning lamp does not illuminate when the
ignition switch is turned ªONº.
IThe ªAIR BAGº warning lamp does not go off about 7 seconds
after the ignition switch is turned ªONº.
IThe ªAIR BAGº warning lamp blinks after about 7 seconds after
the ignition switch is turned ªONº.
2. Visually check SRS components.
1) Diagnosis sensor unit
ICheck diagnosis sensor unit and bracket for dents, cracks and
deformities.
ICheck connectors for damage, and terminals for deformities.
2) Air bag module and steering wheel
IRemove air bag module from steering wheel, instrument panel
or seatback. Check harness cover and connectors for damage,
terminals for deformities, and harness for binding.
IInstall driver air bag module to steering wheel to check fit or
alignment with the wheel.
ICheck steering wheel for excessive free play.
IInstall passenger air bag module to instrument panel to check
fit or alignment with the instrument panel.
IInstall side air bag module to seatback to check fit and align-
ment with the seat.
3) Spiral cable
ICheck spiral cable for dents, cracks, or deformities.
ICheck connectors and protective tape for damage.
ICheck steering wheel for noise, binding or heavy operation.
4) Main harness, air bag harness, body harness, side air bag
module sub-harness
ICheck connectors for poor connections, damage, and termi-
nals for deformities.
ICheck harnesses for binding, chafing or cut.
5) Seat belt pre-tensioner
ICheck harness cover and connectors for damage, terminals
for deformities, and harness for binding.
ICheck belts for damage and anchors for loose mounting.
ICheck retractor for smooth operation.
IPerform self-diagnosis for seat belt pre-tensioner using air bag
warning lamp or CONSULT-II. Refer to ªSRS Operation Checkº
for details. (RS-38)
6) Satellite sensor
ICheck satellite sensor (including bracket portion) for dents,
cracks or deformities.
ICheck connectors for damage, and terminals for deformities.
CAUTION:
Replace previously used special bolts and ground bolt with
new ones.
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
Maintenance Items
RS-14

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