2001 INFINITI QX4 light

System ComponentsNBBR0090
SBR447EB
SBR124B
System DescriptionNBBR0091SENSORNBBR0091S01The sensor unit consists of a gear-shaped sensor rotor and a sen-
sor element. The element contains a bar magnet around which a
coil is wound. The front sensors are installed on the front spindles
and the rear sensors are installed on the rear spindles. As the
wheel rotates, the sensor generates a sine-wave pattern. The fre-
quency and voltage increase(s) as the rotating speed increases.
SBR668E
CONTROL UNIT (BUILT-IN ABS ACTUATOR AND
ELECTRIC UNIT)
NBBR0091S02The control unit computes the wheel rotating speed by the signal
current sent from the sensor. Then it supplies a DC current to the
actuator solenoid valve. It also controls ON-OFF operation of the
valve relay and motor relay. If any electrical malfunction should be
detected in the system, the control unit causes the warning lamp
to light up. In this condition, the ABS will be deactivated by the
control unit, and the vehicle's brake system reverts to normal
operation. (For control unit layout, refer to ABS ACTUATOR AND
ELECTRIC UNIT, BR-33.)
SBR482E
ABS ACTUATOR AND ELECTRIC UNITNBBR0091S03The ABS actuator and electric unit contains:
IAn electric motor and pump
ITwo relays
ISix solenoid valves, each inlet and outlet for
Ð LH front
Ð RH front
Ð Rear
IABS control unit
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DESCRIPTIONABS
System Components
BR-33

8. Vehicle Vibrates Excessively When ABS Is
Operating
=NBBR0078IWhile ABS is operating, brake pedal vibrates slightly. This is
not a problem.
IIf vehicle vibration is greater in the AUTO mode than in the
2WD mode, there is the possibility of failure in the communi-
cation line between the ABS control unit and transfer control
unit. Check and locate the cause of the problem.
1 INSPECTION START
Inspection for excessive vibration of vehicle
SBR508E
©GO TO 2.
2 CARRY OUT SELF-DIAGNOSIS
Perform self-diagnosis for the ABS actuator and electric unit and transfer control unit.
Are there any malfunctions?
Ye s©GO TO 3.
No©GO TO 4.
3 INSPECTION OR REPAIR
Inspect or repair the system according to the self-diagnostic item.
OK©GO TO 4.
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TROUBLE DIAGNOSES FOR SYMPTOMSABS
8. Vehicle Vibrates Excessively When ABS Is Operating
BR-77

Work FlowNBBT0024
SBT842
CUSTOMER INTERVIEWNBBT0024S01Interview the customer, if possible, to determine the conditions that exist when the noise occurs. Use the
Diagnostic Worksheet during the interview to document the facts and conditions when the noise occurs and
any customer's comments; refer to BT-8. This information is necessary to duplicate the conditions that exist
when the noise occurs.
IThe customer may not be able to provide a detailed description or the location of the noise. Attempt to
obtain all the facts and conditions that exist when the noise occurs (or does not occur).
IIf there is more than one noise in the vehicle, be sure to diagnose and repair the noise that the customer
is concerned about. This can be accomplished by test driving the vehicle with the customer.
IAfter identifying the type of noise, isolate the noise in terms of its characteristics. The noise characteris-
tics are provided so the customer, service adviser and technician are all speaking the same language when
defining the noise.
ISqueak Ð (Like tennis shoes on a clean floor)
Squeak characteristics include the light contact/fast movement/brought on by road conditions/hard sur-
faces = higher pitch noise/softer surfaces = lower pitch noises/edge to surface = chirping
ICreak Ð (Like walking on an old wooden floor)
Creak characteristics include firm contact/slow movement/twisting with a rotational movement/pitch depen-
dent on materials/often brought on by activity.
IRattle Ð (Like shaking a baby rattle)
Rattle characteristics include the fast repeated contact/vibration or similar movement/loose parts/missing
clip or fastener/incorrect clearance.
IKnock Ð (Like a knock on a door)
Knock characteristics include hollow sounding/sometimes repeating/often brought on by driver action.
ITick Ð (Like a clock second hand)
Tick characteristics include gentle contacting of light materials/loose components/can be caused by driver
action or road conditions.
IThump Ð (Heavy, muffled knock noise)
Thump characteristics include softer knock/dead sound often brought on by activity.
IBuzz Ð (Like a bumble bee)
Buzz characteristics include high frequency rattle/firm contact.
IOften the degree of acceptable noise level will vary depending upon the person. A noise that you may judge
as acceptable may be very irritating to the customer.
IWeather conditions, especially humidity and temperature, may have a great effect on noise level.
SQUEAK AND RATTLE TROUBLE DIAGNOSES
Work Flow
BT-4

DUPLICATE THE NOISE AND TEST DRIVENBBT0024S02If possible, drive the vehicle with the customer until the noise is duplicated. Note any additional information on
the Diagnostic Worksheet regarding the conditions or location of the noise. This information can be used to
duplicate the same conditions when you confirm the repair.
If the noise can be duplicated easily during the test drive, to help identify the source of the noise, try to dupli-
cate the noise with the vehicle stopped by doing one or all of the following:
1) Close a door.
2) Tap or push/pull around the area where the noise appears to be coming from.
3) Rev the engine.
4) Use a floor jack to recreate vehicle ªtwistº.
5) At idle, apply engine load (electrical load, half-clutch on M/T model, drive position on A/T model).
6) Raise the vehicle on a hoist and hit a tire with a rubber hammer.
IDrive the vehicle and attempt to duplicate the conditions the customer states exist when the noise occurs.
IIf it is difficult to duplicate the noise, drive the vehicle slowly on an undulating or rough road to stress the
vehicle body.
CHECK RELATED SERVICE BULLETINSNBBT0024S03After verifying the customer concern or symptom, check ASIST for Technical Service Bulletins (TSBs) related
to that concern or symptom.
If a TSB relates to the symptom, follow the procedure to repair the noise.
LOCATE THE NOISE AND IDENTIFY THE ROOT CAUSENBBT0024S041. Narrow down the noise to a general area. To help pinpoint the source of the noise, use a listening tool
(Chassis Ear: J-39570, Engine Ear: J-39565 and mechanics stethoscope).
2. Narrow down the noise to a more specific area and identify the cause of the noise by:
Iremoving the components in the area that you suspect the noise is coming from.
Do not use too much force when removing clips and fasteners, otherwise clips and fastener can
be broken or lost during the repair, resulting in the creation of new noise.
Itapping or pushing/pulling the component that you suspect is causing the noise.
Do not tap or push/pull the component with excessive force, otherwise the noise will be eliminated
only temporarily.
Ifeeling for a vibration with your hand by touching the component(s) that you suspect is (are) causing the
noise.
Iplacing a piece of paper between components that you suspect are causing the noise.
Ilooking for loose components and contact marks.
Refer to ªGeneric Squeak and Rattle Troubleshootingº, BT-6.
REPAIR THE CAUSENBBT0024S05IIf the cause is a loose component, tighten the component securely.
IIf the cause is insufficient clearance between components:
þ separate components by repositioning or loosening and retightening the component, if possible.
þ insulate components with a suitable insulator such as urethane pads, foam blocks, felt cloth tape or ure-
thane tape. A Nissan Squeak and Rattle Kit (J-43980) is available through your authorized Nissan Parts
Department.
CAUTION:
Do not use excessive force as many components are constructed of plastic and may be damaged.
Always check with the Parts Department for the latest parts information.
The following materials are contained in the Nissan Squeak and Rattle Kit (J-43980). Each item can be ordered
separately as needed.
URETHANE PADS [1.5 mm (0.059 in) thick]
Insulates connectors, harness, etc.
76268-9E005: 100 x 135 mm (3.94 x 5.31 in)/76884-71L01: 60 x 85 mm (2.36 x 3.35 in)/76884-71L02: 15 x
25 mm (0.59 x 0.98 in)
INSULATOR (Foam blocks)
Insulates components from contact. Can be used to fill space behind a panel.
73982-9E000: 45 mm (1.77 in) thick, 50 x 50 mm (1.97 x 1.97 in)/73982-50Y00: 10 mm (0.39 in) thick, 50 x
50 mm (1.97 x 1.97 in)
INSULATOR (Light foam block)
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SQUEAK AND RATTLE TROUBLE DIAGNOSES
Work Flow (Cont'd)
BT-5

80845-71L00: 30 mm (1.18 in) thick, 30 x 50 mm (1.18 x 1.97 in)
FELT CLOTH TAPE
Used to insulate where movement does not occur. Ideal for instrument panel applications.
68370-4B000: 15 x 25 mm (0.59 x 0.98 in) pad/68239-13E00: 5 mm (0.20 in) wide tape roll
The following materials, not found in the kit, can also be used to repair squeaks and rattles.
UHMW (TEFLON) TAPE
Insulates where slight movement is present. Ideal for instrument panel applications.
SILICONE GREASE
Used in place of UHMW tape that will be visible or not fit.
Note: Will only last a few months.
SILICONE SPRAY
Use when grease cannot be applied.
DUCT TAPE
Use to eliminate movement.
CONFIRM THE REPAIRNBBT0024S06Confirm that the cause of a noise is repaired by test driving the vehicle. Operate the vehicle under the same
conditions as when the noise originally occurred. Refer to the notes on the Diagnostic Worksheet.
Generic Squeak and Rattle TroubleshootingNBBT0025Refer to Table of Contents for specific component removal and installation information.
INSTRUMENT PANELNBBT0025S01Most incidents are caused by contact and movement between:
1. The cluster lid A and instrument panel
2. Acrylic lens and combination meter housing
3. Instrument panel to front pillar garnish
4. Instrument panel to windshield
5. Instrument panel mounting pins
6. Wiring harnesses behind the combination meter
7. A/C defroster duct and duct joint
These incidents can usually be located by tapping or moving the components to duplicate the noise or by
pressing on the components while driving to stop the noise. Most of these incidents can be repaired by apply-
ing felt cloth tape or silicon spray (in hard to reach areas). Urethane pads can be used to insulate wiring har-
ness.
CAUTION:
Do not use silicone spray to isolate a squeak or rattle. If you saturate the area with silicone, you will
not be able to recheck the repair.
CENTER CONSOLENBBT0025S02Components to pay attention to include:
1. Shifter assembly cover to finisher
2. A/C control unit and cluster lid C
3. Wiring harnesses behind audio and A/C control unit
The instrument panel repair and isolation procedures also apply to the center console.
DOORSNBBT0025S03Pay attention to the:
1. Finisher and inner panel making a slapping noise
2. Inside handle escutcheon to door finisher
3. Wiring harnesses tapping
4. Door striker out of alignment causing a popping noise on starts and stops
Tapping or moving the components or pressing on them while driving to duplicate the conditions can isolate
many of these incidents. You can usually insulate the areas with felt cloth tape or insulator foam blocks from
the Nissan Squeak and Rattle Kit (J-43980) to repair the noise.
SQUEAK AND RATTLE TROUBLE DIAGNOSES
Work Flow (Cont'd)
BT-6

TRUNK=NBBT0025S04Trunk noises are often caused by a loose jack or loose items put into the trunk by the owner.
In addition look for:
1. Trunk lid bumpers out of adjustment
2. Trunk lid striker out of adjustment
3. The trunk lid torsion bars knocking together
4. A loose license plate or bracket
Most of these incidents can be repaired by adjusting, securing or insulating the item(s) or component(s) caus-
ing the noise.
SUNROOF/HEADLINERNBBT0025S05Noises in the sunroof/headliner area can often be traced to one of the following:
1. Sunroof lid, rail, linkage or seals making a rattle or light knocking noise
2. Sunvisor shaft shaking in the holder
3. Front or rear windshield touching headliner and squeaking
Again, pressing on the components to stop the noise while duplicating the conditions can isolate most of these
incidents. Repairs usually consist of insulating with felt cloth tape.
SEATSNBBT0025S06When isolating seat noises it's important to note the position the seat is in and the load placed on the seat
when the noise is present. These conditions should be duplicated when verifying and isolating the cause of
the noise.
Cause of seat noise include:
1. Headrest rods and holders
2. A squeak between the seat pad cushion and frame
3. The rear seat back lock and bracket
These noises can be isolated by moving or pressing on the suspected components while duplicating the con-
ditions under which the noise occurs. Most of these incidents can be repaired by repositioning the component
or applying urethane tape to the contact area.
UNDERHOODNBBT0025S07Some interior noises may be caused by components under the hood or on the engine wall. The noise is then
transmitted into the passenger compartment.
Causes of transmitted underhood noises include:
1. Any component mounted to the engine wall
2. Components that pass through the engine wall
3. Engine wall mounts and connectors
4. Loose radiator mounting pins
5. Hood bumpers out of adjustment
6. Hood striker out of adjustment
These noises can be difficult to isolate since they cannot be reached from the interior of the vehicle. The best
method is to secure, move or insulate one component at a time and test drive the vehicle. Also, engine RPM
or load can be changed to isolate the noise. Repairs can usually be made by moving, adjusting, securing, or
insulating the component causing the noise.
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SQUEAK AND RATTLE TROUBLE DIAGNOSES
Generic Squeak and Rattle Troubleshooting (Cont'd)
BT-7

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBEC0002The 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 front 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 On Board Diagnostic (OBD)
System of Engine and A/T
NBEC0003The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:
IBe sure to turn the ignition switch OFF and disconnect the negative battery terminal before any
repair or inspection work. The open/short circuit of related switches, sensors, solenoid valves, etc.
will cause the MIL to light up.
IBe sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MIL to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)
ICertain systems and components, especially those related to OBD, may use a new style slide-
locking type harness connector. For description and how to disconnect, refer to EL-6, ªHARNESS
CONNECTOR (SLIDE-LOCKING TYPE)º.
IBe sure to route and secure the harnesses properly after work. The interference of the harness with
a bracket, etc. may cause the MIL to light up due to the short circuit.
IBe sure to connect rubber tubes properly after work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to the malfunction of the fuel injection system, etc.
IBe sure to erase the unnecessary malfunction information (repairs completed) from the ECM and
TCM (Transmission control module) before returning the vehicle to the customer.
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
EC-14

SEF939Y
10. Tighten fuel tube assembly mounting nuts in numerical
sequence (indicated in the figure at left) and in two stages.
: Tightening torque N´m (kg-m, ft-lb)
1st stage:
9.3 - 10.8 (1.0 - 1.1, 6.9 - 7.9)
2nd stage:
20.6 - 26.5 (2.1 - 2.7, 16 - 19)
11. Install all parts removed in reverse order of removal.
CAUTION:
After properly connecting fuel tube assembly to injector and
fuel hose, check connection for fuel leakage.
SEF058Y
How to Check Idle Speed and Ignition TimingNBEC0607IDLE SPEEDNBEC0607S01IUsing CONSULT-II
Check idle speed in ªDATA MONITORº mode with CONSULT-II.
SEF940Y
IGNITION TIMINGNBEC0607S02Any of following two methods may be used.
IMethod A
a) Attach timing light to loop wire as shown.
b) Check ignition timing.
SEF942Y
IMethod B
a) Remove No. 1 ignition coil.
BASIC SERVICE PROCEDURE
Injector (Cont'd)
EC-42