INFINITI QX4 2001 Factory Service Manual

Page 1761 of 2395

AGI070
HARNESS INDICATIONNBGI0003S0206ILetter designations next to test meter probe indicate harness
(connector) wire color.
IConnector numbers in a single circle M33 indicate harness
connectors.
COMPONENT INDICATIONNBGI0003S0207IConnector numbers in a double circle F211 indicate compo-
nent connectors.
SGI860
SWITCH POSITIONSNBGI0003S0202Switches are shown in wiring diagrams as if the vehicle is in the
normal condition.
A vehicle is in the normal condition when:
Iignition switch is OFF,
Idoors, hood and trunk lid/back door are closed,
Ipedals are not depressed, and
Iparking brake is released.
HOW TO READ WIRING DIAGRAMS
Description (Cont'd)
GI-16

Page 1762 of 2395

SGI862-A
DETECTABLE LINES AND NON-DETECTABLE LINESNBGI0003S0203In some wiring diagrams, two kinds of lines, representing wires,
with different weight are used.
IA line with regular weight (wider line) represents a ªdetectable
line for DTC (Diagnostic Trouble Code)º. A ªdetectable line for
DTCº is a circuit in which ECM (Engine Control Module) can
detect its malfunctions with the on board diagnostic system.
IA line with less weight (thinner line) represents a ªnon-detect-
able line for DTCº. A ªnon-detectable line for DTCº is a circuit
in which ECM cannot detect its malfunctions with the on board
diagnostic system.
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HOW TO READ WIRING DIAGRAMS
Description (Cont'd)
GI-17

Page 1763 of 2395

MULTIPLE SWITCH=NBGI0003S0204The continuity of multiple switch is described in two ways as shown
below.
IThe switch chart is used in schematic diagrams.
IThe switch diagram is used in wiring diagrams.
SGI875
HOW TO READ WIRING DIAGRAMS
Description (Cont'd)
GI-18

Page 1764 of 2395

REFERENCE AREA=NBGI0003S0208The Reference Area of the wiring diagram contains references to
additional electrical reference pages at the end of the manual. If
connector numbers and titles are shown in the Reference Area of
the wiring diagram, these connector symbols are not shown in the
Connector Area.
SGI092A
Super multiple junction (SMJ)
In a wiring diagram, the SMJ connectors include a letter of the
alphabet in the terminal number.
SMJ connector numbers are shown in the Reference Area of the
wiring diagram. SMJ terminal arrangement can be found on the
electrical reference pages at the end of the manual. For terminal
arrangement of these connectors, refer to the ªSUPER MULTIPLE
JUNCTION (SMJ)º electrical reference page at the end of the
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HOW TO READ WIRING DIAGRAMS
Description (Cont'd)
GI-19

Page 1765 of 2395

manual.
Fuse block Ð Junction box (J/B)
Fuse block Ð Junction box (J/B) connector number is shown in the
Reference Area of the wiring diagram. For connector terminal and
fuse arrangement, refer to the ªFUSE BLOCK Ð Junction Box
(J/B)º electrical reference page at the end of the manual.
Fuse and fusible link box
For fuse arrangement in the fuse and fusible link box, refer to the
ªFUSE AND FUSIBLE LINK BOXº electrical reference page at the
end of the manual.
Electrical units
Electrical unit connector symbols are shown in the Connector Area
of the wiring diagram.
However, when there is not enough space to show the connector
terminal arrangement in the Connector Area of the wiring diagram,
the electrical unit connector number is shown in the Reference
Area of the wiring diagram. For electrical unit connector terminal
arrangement, refer to the ªELECTRICAL UNITSº electrical refer-
ence page at the end of the manual. Most of the electrical unit
connectors on this page are shown from the harness side of the
connector.
Joint connector
Joint connector symbols are shown in the connector area of the
wiring diagram. For connector internal wiring layout and joint con-
nector terminal arrangement, refer to the ªJOINT CONNECTOR
(J/C)º electrical reference page at the end of the manual.
HOW TO READ WIRING DIAGRAMS
Description (Cont'd)
GI-20

Page 1766 of 2395

NBGI0011
Connector and Terminal Pin KitNBGI0011S01Use the connector and terminal pin kit listed below when replacing
connectors or terminals.
The connector and terminal pin kit contains some of the most
commonly used INFINITI connectors and terminals.
Tool number
(Kent-Moore No.)
Tool nameDescription
Ð
(J38751-95INF)
Connector and terminal
pin kit
Ð
(J42992-98KIT)
OBD Terminal Repair Kit
SGI109A
How to Probe ConnectorsNBGI0011S02Connector damage and an intermittent connection can result from
improperly probing of the connector during circuit checks.
The probe of a digital multimeter (DMM) may not correctly fit the
connector cavity. To correctly probe the connector, follow the pro-
cedures below using a ªTº pin. For the best contact grasp the ªTº
pin using an alligator clip.
SGI841
PROBING FROM HARNESS SIDENBGI0011S0201Standard type (not waterproof type) connector should be probed
from harness side with ªTº pin.
IIf the connector has a rear cover such as a ECM
connector, remove the rear cover before probing the ter-
minal.
IDo not probe waterproof connector from harness side.
Damage to the seal between wire and connector may
result.
SEL265V
PROBING FROM TERMINAL SIDENBGI0011S0202Female Terminal
IThere is a small notch above each female terminal. Probe
each terminal with the ªTº pin through the notch.
Do not insert any object other than the same type male
terminal into female terminal.
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HOW TO CHECK TERMINAL
Connector and Terminal Pin Kit
GI-21

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SEL266V
ISome connectors do not have a notch above each terminal. To
probe each terminal, remove the connector retainer to make
contact space for probing.
SEL267V
Male Terminal
Carefully probe the contact surface of each terminal using a ªTº pin.
Do not bend terminal.
How to Check Enlarged Contact Spring of
Terminal
NBGI0011S03An enlarged contact spring of a terminal may create intermittent
signals in the circuit.
If the intermittent open circuit occurs, follow the procedure below
to inspect for open wires and enlarged contact spring of female
terminal.
SEL270V
1. Assemble a male terminal and approx. 10 cm (3.9 in) of wire.
Use a male terminal which matches the female terminal.
2. Disconnect the suspected faulty connector and hold it terminal
side up.
SEL271V
3. While holding the wire of the male terminal, try to insert the
male terminal into the female terminal.
Do not force the male terminal into the female terminal
with your hands.
HOW TO CHECK TERMINAL
How to Probe Connectors (Cont'd)
GI-22

Page 1768 of 2395

SEL272V
4. While moving the connector, check whether the male terminal
can be easily inserted or not.
SEL273V
IIf the male terminal can be easily inserted into the female
terminal, replace the female terminal.
SEL275V
Waterproof Connector InspectionNBGI0011S04If water enters the connector, it can short interior circuits. This may
lead to intermittent problems.
Check the following items to maintain the original waterproof char-
acteristics.
RUBBER SEAL INSPECTIONNBGI0011S0401IMost waterproof connectors are provided with a rubber seal
between the male and female connectors. If the seal is
missing, the waterproof performance may not meet specifica-
tions.
IThe rubber seal may come off when connectors are discon-
nected. Whenever connectors are reconnected, make sure the
rubber seal is properly installed on either side of male or
female connector.
WIRE SEAL INSPECTIONNBGI0011S0402The wire seal must be installed on the wire insertion area of a
waterproof connector. Be sure that the seal is installed properly.
SEL330V
Terminal Lock InspectionNBGI0011S05Check for unlocked terminals by pulling wire at the end of connec-
tor. An unlocked terminal may create intermittent signals in the
circuit.
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HOW TO CHECK TERMINAL
How to Check Enlarged Contact Spring of Terminal (Cont'd)
GI-23

Page 1769 of 2395

NBGI0004
Work FlowNBGI0004S01
SGI838
STEP DESCRIPTION
STEP 1 Get detailed information about the conditions and the environment when the incident occurred.
The following are key pieces of information required to make a good analysis:
WHATVehicle Model, Engine, Transmission and the System (i.e. Radio).
WHENDate, Time of Day, Weather Conditions, Frequency.
WHERERoad Conditions, Altitude and Traffic Situation.
HOWSystem Symptoms, Operating Conditions (Other Components Interaction).
Service History and if any After Market Accessories have been installed.
STEP 2 Operate the system, road test if necessary.
Verify the parameter of the incident.
If the problem can not be duplicated, refer to ªIncident Simulation Testsº next page.
STEP 3 Get the proper diagnosis materials together including:
POWER SUPPLY ROUTING
System Operation Descriptions
Applicable Service Manual Sections
Check for any Service Bulletin.
Identify where to begin diagnosis based upon your knowledge of the system operation and the cus-
tomer comments.
STEP 4 Inspect the system for mechanical binding, loose connectors or wiring damage.
Determine which circuits and components are involved and diagnose using the Power Supply Routing
and Harness Layouts.
STEP 5 Repair or replace the incident circuit or component.
STEP 6 Operate the system in all modes. Verify the system works properly under all conditions. Make sure you
have not inadvertently created a new incident during your diagnosis or repair steps.
HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Work Flow
GI-24

Page 1770 of 2395

Incident Simulation TestsNBGI0004S02INTRODUCTIONNBGI0004S0201Sometimes the symptom is not present when the vehicle is brought
in for service. If possible, re-create the conditions present at the
time of the incident. Doing so may help avoid a No Trouble Found
Diagnosis. The following section illustrates ways to simulate the
conditions/environment under which the owner experiences an
electrical incident.
The section is broken into the six following topics:
IVehicle vibration
IHeat sensitive
IFreezing
IWater intrusion
IElectrical load
ICold or hot start up
Get a thorough description of the incident from the customer. It is
important for simulating the conditions of the problem.
VEHICLE VIBRATIONNBGI0004S0202The problem may occur or become worse while driving on a rough
road or when engine is vibrating (idle with A/C on). In such a case,
you will want to check for a vibration related condition. Refer to the
illustration below.
Connectors & Harness
Determine which connectors and wiring harness would affect the
electrical system you are inspecting.Gentlyshake each connec-
tor and harness while monitoring the system for the incident you
are trying to duplicate. This test may indicate a loose or poor elec-
trical connection.
Hint
Connectors can be exposed to moisture. It is possible to get a thin
film of corrosion on the connector terminals. A visual inspection
may not reveal this without disconnecting the connector. If the
problem occurs intermittently, perhaps the problem is caused by
corrosion. It is a good idea to disconnect, inspect and clean the
terminals on related connectors in the system.
Sensors & Relays
Gentlyapply a slight vibration to sensors and relays in the system
you are inspecting.
This test may indicate a loose or poorly mounted sensor or relay.
SGI839
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HOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENT
Incident Simulation Tests
GI-25

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