2001 INFINITI QX4 Electrical Wiring

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBEL0001The 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 DiagnosisNBEL0002When 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
Check for any Service bulletins before servicing the vehicle.
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
EL-4

CEL083
InspectionNBEL0007FUSENBEL0007S01IIf fuse is blown, be sure to eliminate cause of problem
before installing new fuse.
IUse fuse of specified rating. Never use fuse of more than
specified rating.
IDo not partially install fuse; always insert it into fuse
holder properly.
IRemove fuse for ªELECTRICAL PARTS (BAT)º if vehicle is
not used for a long period of time.
MEL944F
FUSIBLE LINKNBEL0007S02A melted fusible link can be detected either by visual inspection or
by feeling with finger tip. If its condition is questionable, use circuit
tester or test lamp.
CAUTION:
IIf fusible link should melt, it is possible that critical circuit
(power supply or large current carrying circuit) is shorted.
In such a case, carefully check and eliminate cause of
problem.
INever wrap outside of fusible link with vinyl tape. Impor-
tant: Never let fusible link touch any other wiring harness,
vinyl or rubber parts.
SEL109W
CIRCUIT BREAKER (PTC THERMISTOR TYPE)NBEL0007S03The PTC thermister generates heat in response to current flow.
The temperature (and resistance) of the thermister element varies
with current flow. Excessive current flow will cause the element's
temperature to rise. When the temperature reaches a specified
level, the electrical resistance will rise sharply to control the circuit
current.
Reduced current flow will cause the element to cool. Resistance
falls accordingly and normal circuit current flow is allowed to
resume.
POWER SUPPLY ROUTING
Inspection
EL-16

Trouble DiagnosesNBEL0033
Symptom Possible cause Repair order
Turn signal and hazard warning
lamps do not operate.1. Hazard switch
2. Combination flasher unit
3. Open in combination flasher
unit circuit1. Check hazard switch.
2. Refer to combination flasher unit check.
3. Check wiring to combination flasher unit for open
circuit.
Turn signal lamps do not operate
but hazard warning lamps operate.1. 7.5A fuse
2. Hazard switch
3. Combination switch (turn signal)
4. Open in combination switch
(turn signal) circuit1. Check 7.5A fuse [No. 12, located in fuse block
(J/B)]. Turn ignition switch ON and verify battery
positive voltage is present at terminal 2 of hazard
switch.
2. Check hazard switch.
3. Check combination switch (turn signal).
4. Check the wire between combination flasher unit
terminal 3 and combination switch (turn signal) ter-
minal 1 for open circuit.
Hazard warning lamps do not oper-
ate but fog lamps (turn signal)
operate.1. 15A fuse
2. Hazard switch
3. Open in hazard switch circuit1. Check 15A fuse [No. 20, located in fuse block (J/B)].
Verify battery positive voltage is present at terminal
3 of hazard switch.
2. Check hazard switch.
3. Check the wire between combination flasher unit
terminal 3 and hazard switch terminal 4 for open cir-
cuit.
Front fog lamp (turn signal) LH or
RH does not operate.1. Bulb
2. Grounds E13 and E41
3. Open in front fog lamp (turn sig-
nal) circuit1. Check bulb.
2. Check grounds E13 and E41.
3. Check harness between front fog lamp (turn signal)
and combination switch.
Rear combination lamp LH does
not operate.1. Bulb
2. Grounds B11, B22 and D210
3. Open in rear combination lamp
LH circuit1. Check bulb.
2. Check grounds B11, B22 and D210.
3. Check harness between rear combination lamp LH
and hazard switch.
Rear combination lamp RH does
not operate.1. Bulb
2. Grounds B55 and B75
3. Open in rear combination lamp
RH circuit1. Check bulb.
2. Check grounds B55 and B75.
3. Check harness between rear combination lamp RH
and hazard switch.
LH and RH turn indicators do not
operate.1. Ground 1. Check grounds M4, M66 and M147.
LH or RH turn indicator does not
operate.1. Bulb
2. Open in turn indicator circuit1. Check bulb in combination meter.
2. Check harness between combination meter and haz-
ard switch.
SEL122E
Electrical Components InspectionNBEL0034COMBINATION FLASHER UNIT CHECKNBEL0034S01IBefore checking, ensure that bulbs meet specifications.
IConnect a battery and test lamp to the combination flasher
unit, as shown. Combination flasher unit is properly function-
ing if it blinks when power is supplied to the circuit.
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TURN SIGNAL AND HAZARD WARNING LAMPS
Trouble Diagnoses
EL-79

SEL062WA
Fuel Warning Lamp Sensor CheckNBEL01661. Turn ignition switch ªOFFº.
2. Disconnect fuel level sensor unit harness connector B12.
3. Connect a resistor (80W) between fuel tank gauge unit harness
connector terminals 2 and 3.
4. Turn ignition switch ªONº.
The fuel warning lamp should come on.
NOTE:
ECM might store the 1st trip DTC P0180 during this inspection.
If the DTC is stored in ECM memory, erase the DTC after recon-
necting fuel tank gauge unit harness connector.
Refer to EC-60, ªHOW TO ERASE EMISSION-RELATED DIAG-
NOSTIC INFORMATIONº.
MEL425F
Electrical Components InspectionNBEL0051OIL PRESSURE SWITCH CHECKNBEL0051S02
Oil pressure
kPa (kg/cm2, psi)Continuity
Engine startMore than 10 - 20
(0.1-0.2,1-3)NO
Engine stopLess than 10 - 20
(0.1-0.2,1-3)YES
Check the continuity between the terminals of oil pressure switch
and body ground.
SEL901F
DIODE CHECKNBEL0051S03ICheck continuity using an ohmmeter.
IDiode is functioning properly if test results are as shown in the
figure at left.
ICheck diodes at the combination meter harness connector
instead of checking them on the combination meter assembly.
Refer to EL-115, ªWARNING LAMPº wiring diagrams.
NOTE:
Specification may vary depending on the type of tester. Before
performing this inspection, be sure to refer to the instruction
manual for the tester to be used.
WARNING LAMPS
Fuel Warning Lamp Sensor Check
EL-122

ASCD BRAKE/STOP LAMP SWITCH CHECK=NBEL0218S04
1 CHECK ASCD BRAKE SWITCH CIRCUIT
1. Disconnect ASCD control unit harness connector.
2. Turn ignition switch ON.
3. Check voltage between ASCD control unit harness connector terminal 8 and ground.
SEL258WD
OK or NG
OK©GO TO 2.
NG©Check the following.
IASCD brake switch
Refer to ªElectrical Component Inspectionº (EL-239).
IPark/neutral position switch
Refer to ªElectrical Component Inspectionº (EL-239).
IPark/neutral position relay
IHarness for open or short
2 CHECK STOP LAMP SWITCH CIRCUIT
1. Disconnect ASCD control unit harness connector.
2. Check voltage between ASCD control unit harness connector terminal 23 and ground.
SEL259WB
Refer to wiring diagram in EL-226.
OK or NG
OK©ASCD brake/stop lamp switch is OK.
NG©Check the following.
I10A fuse [No. 14, located in the fuse block (J/B)]
IHarness for open or short between ASCD control unit and stop lamp switch
IHarness for open or short between fuse and stop lamp switch
IStop lamp switch
Refer to ªElectrical Component Inspectionº (EL-239).
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses (Cont'd)
EL-233

NBEL0145
Use the chart below to find out what each wiring
diagram code stands for.
Refer to the wiring diagram code in the alphabetical
index to find the location (page number) of each
wiring diagram.
Code Section Wiring Diagram Name
1STSIG AT A/T 1ST Signal
2NDSIG AT A/T 2ND Signal
3RDSIG AT A/T 3RD Signal
4THSIG AT A/T 4TH Signal
A/C, A HA Auto Air Conditioner
AAC/V EC IACV-AAC Valve
ABS BR Anti-lock Brake System
AP/SEN EC Absolute Pressure Sensor
ASCD EL Automatic Speed Control Device
AT/C EC A/T Control
ATDIAG EC A/T Diagnosis Communication
Line
AT/IND EL A/T Indicator Lamp
AUDIO EL Audio
AUT/DP EL Automatic Drive Positioner
BA/FTS AT A/T Fluid Temperature Sensor
and TCM Power Supply
BACK/L EL Back-up Lamp
BYPS/V EC Vacuum Cut Valve Bypass Valve
CHARGE SC Charging System
CHIME EL Warning Chime
CIGAR EL Cigarette Lighter
CLOCK EL Clock
COMPAS EL Compass and Thermometer
D/LOCK EL Power Door Lock
DEF EL Rear Window Defogger
DTRL EL Headlamp Ð With Daytime Light
System Ð
ECTS EC Engine Coolant Temperature Sen-
sor
ENGSS AT Engine Speed Signal
F/FOG EL Front Fog Lamp
F/LID EL Fuel Lid Opener
F/PUMP EC Fuel Pump Control
FICD EC IACV-FICD Solenoid Valve
FLS1 EC Fuel Gauge
Code Section Wiring Diagram Name
FLS2 EC Fuel Gauge
FLS3 EC Fuel Gauge
FTS AT A/T Fluid Temperature Sensor
FUELLH EC Fuel Injection System Function
(Left Bank)
FUELRH EC Fuel Injection System Function
(Right Bank)
H/AIM EL Headlamp Aiming Control System
H/LAMP EL Headlamp
HORN EL Horn
HSEAT EL Heated Seat
IATS EC Intake Air Temperature Sensor
IGN/SG EC Ignition Signal
ILL EL Illumination
INJECT EC Injector
INT/L EL Interior, Spot, Vanity Mirror, and
Luggage Room Lamps
IVC-L EC Intake Valve Timing Control Sole-
noid Valve LH
IVC-R EC Intake Valve Timing Control Sole-
noid Valve RH
IVCS EL INFINITI Communicator
IVCS-L EC Intake Valve Timing Control Posi-
tion Sensor LH
IVCS-R EC Intake Valve Timing Control Posi-
tion Sensor RH
KS EC Knock Sensor
LAN AT A/T Communication Line
LOAD EC Electrical Load Signal
LPSV AT Line Pressure Solenoid Valve
MAFS EC Mass Air Flow Sensor
MAIN AT Main Power Supply and Ground
Circuit
MAIN EC Main Power Supply and Ground
Circuit
METER EL Speedometer, Tachometer, Temp.,
Oil, and Fuel Gauges
MIL/DL EC MIL and Data Link Connectors
MIRROR EL Door Mirror
MULTI EL Multi-remote Control System
NATS EL IVIS (Infiniti Vehicle Immobiliser
System)
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WIRING DIAGRAM CODES (CELL CODES)
EL-457

GENERAL INFORMATION
SECTION
GI
CONTENTS
PRECAUTIONS...............................................................3
Precautions ..................................................................3
PRECAUTIONS FOR SUPPLEMENTAL
RESTRAINT SYSTEM (SRS)²AIR BAG²AND
²SEAT BELT PRE-TENSIONER²
.................................3
PRECAUTIONS FOR IVIS (INFINITI VEHICLE
IMMOBILIZER SYSTEM - NATS)
.................................3
PRECAUTIONS FOR INFINITI COMMUNICATOR
(IVCS)
.......................................................................4
GENERAL PRECAUTIONS.........................................5
PRECAUTIONS FOR MULTIPORT FUEL
INJECTION SYSTEM OR ENGINE CONTROL
SYSTEM
...................................................................6
PRECAUTIONS FOR THREE WAY CATALYST...........6
PRECAUTIONS FOR HOSES.....................................7
PRECAUTIONS FOR ENGINE OILS...........................8
PRECAUTIONS FOR FUEL........................................8
PRECAUTIONS FOR AIR CONDITIONING..................8
HOW TO USE THIS MANUAL........................................9
HOW TO READ WIRING DIAGRAMS.......................... 11
Sample/Wiring Diagram - EXAMPL - ........................ 11
OPTIONAL SPLICE..................................................12
Description .................................................................13
CONNECTOR SYMBOLS.........................................15
HARNESS INDICATION...........................................16
COMPONENT INDICATION......................................16
SWITCH POSITIONS...............................................16
DETECTABLE LINES AND NON-DETECTABLE
LINES
.....................................................................17
MULTIPLE SWITCH.................................................18
REFERENCE AREA.................................................19
HOW TO CHECK TERMINAL.......................................21
Connector and Terminal Pin Kit.................................21
How to Probe Connectors .........................................21
PROBING FROM HARNESS SIDE............................21
PROBING FROM TERMINAL SIDE...........................21
How to Check Enlarged Contact Spring of
Terminal .....................................................................22
Waterproof Connector Inspection ..............................23
RUBBER SEAL INSPECTION...................................23
WIRE SEAL INSPECTION........................................23Terminal Lock Inspection ...........................................23
HOW TO PERFORM EFFICIENT DIAGNOSIS
FOR AN ELECTRICAL INCIDENT...............................24
Work Flow ..................................................................24
Incident Simulation Tests ...........................................25
INTRODUCTION......................................................25
VEHICLE VIBRATION..............................................25
HEAT SENSITIVE....................................................26
FREEZING..............................................................26
WATER INTRUSION................................................27
ELECTRICAL LOAD.................................................27
COLD OR HOT START UP.......................................27
Circuit Inspection .......................................................27
INTRODUCTION......................................................27
TESTING FOR²OPENS²IN THE CIRCUIT................28
TESTING FOR²SHORTS²IN THE CIRCUIT..............29
GROUND INSPECTION...........................................30
VOLTAGE DROP TESTS..........................................30
CONTROL UNIT CIRCUIT TEST...............................32
HOW TO FOLLOW TROUBLE DIAGNOSIS................34
How to Follow Test Groups in Trouble Diagnosis .....35
Key to Symbols Signifying Measurements or
Procedures.................................................................36
CONSULT-II CHECKING SYSTEM...............................38
Function and System Application ..............................38
Nickel Metal Hydride Battery Replacement...............39
Checking Equipment..................................................39
CONSULT-II Data Link Connector (DLC) Circuit ......40
INSPECTION PROCEDURE.....................................40
IDENTIFICATION INFORMATION................................41
Model Variation ..........................................................41
PREFIX AND SUFFIX DESIGNATIONS.....................41
Identification Number .................................................41
VEHICLE IDENTIFICATION NUMBER
ARRANGEMENT
.....................................................42
IDENTIFICATION PLATE..........................................42
ENGINE SERIAL NUMBER.......................................43
AUTOMATIC TRANSMISSION NUMBER...................43
TRANSFER SERIAL NUMBER..................................43
Dimensions ................................................................43
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PrecautionsNBGI0001Observe the following precautions to ensure safe and proper
servicing. These precautions are not described in each indi-
vidual section.
SGI646
PRECAUTIONS FOR SUPPLEMENTAL RESTRAINT
SYSTEM (SRS) ªAIR BAGº AND ªSEAT BELT
PRE-TENSIONERº
NBGI0001S01The 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 passen-
ger 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 steering wheel), front pas-
senger 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 compo-
nents 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 personal 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 IVIS (INFINITI VEHICLE
IMMOBILIZER SYSTEM Ð NATS)
NBGI0001S08IVIS (NATS) will immobilize the engine if someone tries to start it
without the registered key of IVIS (NATS).
Both of the originally supplied ignition key IDs have been IVIS
(NATS) registered.
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PRECAUTIONS
Precautions
GI-3