2001 INFINITI QX4 Oil sensor

ComponentsNBAX0028
SRA756A
RemovalNBAX0029CAUTION:
IBefore removing the rear axle, disconnect the ABS wheel
sensor from the assembly. Then move it away from the
axle. Failure to do so may result in damage to the sensor
wires and the sensor becoming inoperative.
IWheel bearing does not require maintenance.
IIf growling noise is emitted from wheel bearing during
operation, replace wheel bearing assembly.
IIf the wheel bearing assembly is removed, it must be renewed.
The old assembly must not be re-used.
SAX002
1. Disconnect parking brake cable and brake tube.
2. Remove nuts securing wheel bearing cage with baffle plate.
SRA758A
3. Draw out axle shaft with Tool.
When drawing out axle shaft, be careful not to damage oil seal.
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REAR AXLE
Components
AX-19

SRA759A
4. Remove oil seal with a screwdriver.
Do not reuse oil seal once it is removed.
Always install new one.
5. Remove ABS sensor rotor.
SRA104
6. Unbend lock washer with a screwdriver.
Do not reuse lock washer once removed. Always install new
one.
SRA728
7. Remove bearing lock nut with Tool.
SRA729-B
8. Remove wheel bearing together with bearing cage and baffle
plate from axle shaft.
SRA106
9. Remove grease seal with a screwdriver.
10. Remove wheel bearing assembly with a brass drift.
REAR AXLE
Removal (Cont'd)
AX-20

SRA763A
6. Check wheel bearing preload.
a. Turn bearing cage (with respect to axle shaft) two or three
times. It must turn smoothly.
b. Attach spring gauge to bearing cage bolt (as shown at left) and
pull it at a speed of 10 rpm to measure preload.
Spring gauge indication:
6.9 - 48.1 N (0.7 - 4.9 kg, 1.5 - 10.8 lb)
SRA292A
7. Install new oil seal to rear axle housing using a suitable tool.
After installing new oil seal, coat sealing lip with multi-pur-
pose grease.
SRA012
8. Press ABS sensor rotor onto axle shaft until it contacts wheel
bearing lock nut.
9. Position axle shafts in rear axle housing with Tool as a guide.
Be careful not to damage oil seal.
SRA755A
10. Check axial end play.
a. Check that wheel bearings operate smoothly.
b. Check axial end play.
Axial end play:
0mm(0in)
Service Data and Specifications (SDS)
WHEEL BEARING (REAR)NBAX0032
Wheel bearing axial end play0mm(0in)
Wheel bearing lock nut tightening torque 245 - 314 N´m (25 - 32 kg-m, 181 - 231 ft-lb)
Wheel bearing preload measured at bearing cage bolt 6.9 - 48.1 N (0.7 - 4.9 kg, 1.5 - 10.8 lb)
REAR AXLE
Installation (Cont'd)
AX-22

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBBR0001The 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.
SBR686C
Precautions for Brake SystemNBBR0002IUse brake fluid ªDOT 3º.
INever reuse drained brake fluid.
IBe careful not to splash brake fluid on painted areas; it
may cause paint damage. If brake fluid is splashed on
painted areas, wash it away with water immediately.
ITo clean master cylinder parts, disc brake caliper parts or
wheel cylinder parts, use clean brake fluid.
INever use mineral oils such as gasoline or kerosene. They
will ruin rubber parts of hydraulic system.
IUse flare nut wrench when removing and installing brake
tubes.
IAlways torque brake lines when installing.
WARNING:
IClean brakes with a vacuum dust collector to minimize
risk of health hazard from powder caused by friction.
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PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
BR-3

InspectionNBBR0014CAUTION:
ICarefully monitor brake fluid level at master cylinder.
IUse new brake fluid ªDOT 3º.
IBe careful not to splash brake fluid on painted areas; it
may cause paint damage. If brake fluid is splashed on
paint areas, wash it away with water immediately.
IDepress pedal slowly when raising front brake pressure.
ICheck rear brake pressure 2 seconds after front brake
pressure reaches specified value.
IDisconnect harness connectors from ABS actuator and
electric unit before checking.
SBR212E
1. Park vehicle on a level surface with vehicle unloaded*.
* Fuel, radiator coolant and engine oil full. Spare tire, jack,
hand tools and mats in designated positions.
2. Press a lever to the stopper bolt, then check length ªBº as fol-
lows:
Length ªBº Reference (Length ªLº)
207.7 mm (8.18 in) 217.3 mm (8.56 in)
3. If length ªBº is not within specification, adjust sensor spring
length.
Removal and InstallationNBBR0015CAUTION:
IRefill with new brake fluid ªDOT 3º.
IBe careful not to splash brake fluid on painted areas; it
may cause paint damage. If brake fluid is splashed on
painted areas, wash it away with water immediately.
IDo not reuse Load Sensing Valve once it is disassembled.
IReplace damaged Load Sensing Valve as an assembly.
IWhen disassembling, apply multi-purpose grease to all
rubbing areas.
LOAD SENSING VALVE (4WD)
Inspection
BR-12

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

Malfunction Code/Symptom ChartNBBR0101
Code No. (No. of warning lamp flashes) Malfunctioning part Reference Page
12 Self-diagnosis could not detect any malfunctions. Ð
17*4 G sensor and circuit BR-65
18*1 Sensor rotor BR-56
21*1 Front right sensor (open-circuit) BR-56
22*1 Front right sensor (short-circuit) BR-56
25*1 Front left sensor (open-circuit) BR-56
26*1 Front left sensor (short-circuit) BR-56
31*1 Rear right sensor (open-circuit) BR-56
32*1 Rear right sensor (short-circuit) BR-56
35*1 Rear left sensor (open-circuit) BR-56
36*1 Rear left sensor (short-circuit) BR-56
41 Actuator front right outlet solenoid valve BR-59
42 Actuator front right inlet solenoid valve BR-59
45 Actuator front left outlet solenoid valve BR-59
46 Actuator front left inlet solenoid valve BR-59
55 Actuator rear outlet solenoid valve BR-59
56 Actuator rear inlet solenoid valve BR-59
57*2 Power supply (Low voltage) BR-63
61*3 Actuator motor or motor relay BR-61
63 Solenoid valve relay BR-59
71 Control unit BR-68
Warning lamp stays on when ignition
switch is turned ON.Control unit power supply circuit
Warning lamp bulb circuit
Control unit or control unit connector
Solenoid valve relay stuck
Power supply for solenoid valve relay coilBR-74
ABS works frequently Ð BR-69
Unexpected pedal action Ð BR-69
Long stopping distance Ð BR-70
ABS does not work Ð BR-71
Pedal vibration and noise Ð BR-71
Warning lamp does not come on
when ignition switch is turned ON.Fuse, warning lamp bulb or warning lamp circuit
Control unitBR-72
Vehicle vibrates excessively when ABS is
operating.ABS control unit to TCM circuit BR-77
*1: If one or more wheels spin on a rough or slippery road for 40 seconds or more, the ABS warning lamp will illuminate. This does not
indicate a malfunction. Only in the case of the short-circuit (Code Nos. 26, 22, 32 and 36), after repair the ABS warning lamp also illu-
minates when the ignition switch is turned ON. In this case, drive the vehicle at speeds greater than 30 km/h (19 MPH) for approxi-
mately 1 minute as specified in ªSELF-DIAGNOSIS PROCEDUREº, BR-41. Check to ensure that the ABS warning lamp goes out while
the vehicle is being driven.
*2: The trouble code ª57º, which refers to a low power supply voltage, does not indicate that the ABS control unit is malfunctioning. Do
not replace the ABS control unit with a new one.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONABS
Malfunction Code/Symptom Chart
BR-54

Service NoticeNBBT0001IWhen removing or installing various parts, place a cloth or padding onto the vehicle body to prevent
scratches.
IHandle trim, molding, instruments, grille, etc. carefully during removing or installing. Be careful not to soil
or damage them.
IApply sealing compound where necessary when installing parts.
IWhen applying sealing compound, be careful that the sealing compound does not protrude from parts.
IWhen replacing any metal parts (for example body outer panel, members, etc.), be sure to take rust pre-
vention measures.
Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBBT0002The 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
Service Notice
BT-2