2001 INFINITI QX4 lock

SBR686C
Removal and InstallationNBSU00261. Support axle and suspension components with a suitable jack
and block.
2. Disconnect brake hydraulic line and parking brake cables at
back plates.
CAUTION:
IUse flare nut wrench when removing and installing brake
tubes.
IBefore removing the rear suspension assembly, discon-
nect the ABS wheel sensor from the assembly. Then move
it away from the rear suspension assembly. Failure to do
so may result in damage to the sensor wires and the sen-
sor becoming inoperative.
3. Remove stabilizer bar from body.
4. Remove upper links and lower links from body.
5. Remove panhard rod from body.
6. Disconnect rear end of propeller shaft. Refer to PD-6,
ªRemoval and Installationº.
7. Remove upper end nuts of shock absorber.
SRA935
Final tightening for rubber parts requires to be carried out
under unladen condition with tires on ground.
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REAR SUSPENSION
Removal and Installation
SU-17

Description of Electrical PartsNBTF0067TRANSFER MOTORNBTF0067S011. The transfer motor drives the sub-oil pump to provide proper lubrication and oil pressure control when the
vehicle is at standstill, during low-speed operations or is being driven in reverse.
2. The main oil pump is operated by the driving force of the mainshaft. In other words, sufficient oil pressure
buildup does not occur when the vehicle is at standstill or during low-speed operations. While the vehicle
is being driven in reverse, the main oil pump rotates in the reverse direction. Therefore the main oil pump
does not discharge oil pressure. During any of the above vehicle operations, the transfer motor drives the
sub-oil pump to compensate for insufficient oil pressure.
3. The transfer motor operates as follows:
1) The motor relay turns OFF in the 2WD mode.
2) The motor relay operates as described in the table below in modes other than the 2WD mode.
Table 1
PNP switch ªRº position VFF (Vehicle speed) A/T position Motor relay drive command
ON Ð R ON
OFF0 km/hPositions other than the ªPº or
ªNº positionsON
ЪPº or ªNº position (See Table
2.)Ð
0 < VFF%30 km/h Ð ON
30 < VFF < 35 km/h Ð HOLD
35 km/h%VFF Ð OFF
Table 2
A/T position N-4L SW 4WD modeThrottle position
0 - 0.07/8 0.07/8 - 1/8 1/8 - MAX
NOFFLOCK (4H) ON ON ON
Positions other than
the LOCK position
(2WD or AUTO)See NOTE. HOLD ON
ON Ð See NOTE. HOLD ON
P Ð Ð See NOTE. HOLD ON
NOTE:
OFF (after 2.5 seconds have elapsed.)
4. 4WD shift switch, PNP switch, Neutral-4LO switch, vehicle speed sensor and throttle position sensor are
used in conjunction with the transfer motor.
WAIT DETECTION SWITCHNBTF0067S021. The wait detection switch releases the ªboomingº torque produced in the propeller shaft. After the release
of the ªboomingº torque, the wait detection switch helps provide the 4WD lock gear (clutch drum) shifts.
A difference may occur between the operation (ª4LOº to ª4Hº shift only) of the 4WD shift switch and actual
drive mode. At this point, the wait detection switch senses an actual drive mode.
2. The wait detection switch operates as follows:
4WD lock gear (clutch drum) locked: ON
4WD lock gear (clutch drum) released: OFF
3. The wait detection switch senses an actual drive mode and the 4WD shift indicator lamp indicates the
vehicle drive mode.
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ALL-MODE 4WD SYSTEM
Description of Electrical Parts
TF-15

SMT963D
12. Monitored data are displayed.
DATA MONITOR ITEMSNBTF0012S04q: StandardH: Option
Item [Unit]Monitor item
Remarks
ECU input
signalsMain sig-
nalsItem menu
selection
Revolution sensor-front [km/h (MPH)]qHRevolution sensor installed on T/F
Revolution sensor-rear [km/h (MPH)]qHVehicle speed sensor´A/T
Engine speed [rpm]qH
Throttle position sensor [V]qH
Transfer fluid temperature sensor [V]qH
Battery voltage [V]qH
2WD switch [ON-OFF]qH2WD switch of 4WD shift switch
AUTO switch [ON-OFF]qHAUTO switch of 4WD shift switch
Lock switch [ON-OFF]qH4H switch of 4WD shift switch
4L switch [ON-OFF]qH4LO switch of 4WD shift switch
N position switch TF [ON-OFF]qHN position switch of transfer
Line pressure switch [ON-OFF]qHLine pressure switch
Clutch pressure switch [ON-OFF]qHClutch pressure switch
ATP switch [ON-OFF]qH
N position switch [ON-OFF]qHªNº position on A/T PNP switch
R position switch [ON-OFF]qHªRº position on A/T PNP switch
P position switch [ON-OFF]qHªPº position on A/T PNP switch
Closed throttle position switch
[ON/OFF]qHIdle contact of throttle position switch
ABS operation switch [ON-OFF]qHABS operation switch
Wait detection switch [ON-OFF]qH
Throttle openingqHThrottle opening recognized by transfer control
unit
4WD-modeqH4WD-mode recognized by transfer control unit
(2W, AUTO, 4H & 4LO)
Vehicle speed comp [km/h (MPH)]qHVehicle speed recognized by transfer control
unit
*Control torque [N´m (kg-m, ft-lb)]qHCalculated torque recognized by transfer control
unit
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis with CONSULT-II (Cont'd)
TF-34

Item [Unit]Monitor item
Remarks
ECU input
signalsMain sig-
nalsItem menu
selection
Duty solenoid valve [%]
(Transfer 4WD solenoid valve)qH
2-4WD shift solenoid valve [ON-OFF]qH
Control signal outputs of transfer control unit Transfer motor relay [ON-OFF]qH
Shift activating 1 [ON-OFF]qH
Shift activating 2 [ON-OFF]qH
2-4WD shift solenoid valve monitor
[ON-OFF]H
Check signal (re-input signal) of transfer control
unit control signal output is displayed. If circuit
is shorted or open, ON/OFF state does not
change. Transfer motor relay monitor [ON-OFF]H
Shift activating monitor 1 [ON-OFF]H
Shift activating monitor 2 [ON-OFF]H
4WD fail lamp [ON-OFF]qHTransfer control unit control signal output for
4WD warning lamp (left)
Shift position switch 1 [ON-OFF]qH
Shift position switch 2 [ON-OFF]qH
2WD indicator lamp [ON-OFF]HTransfer control unit control signal output for
4WD shift indicator lamp (rear)
AUTO indicator lamp [ON-OFF]HTransfer control unit control signal output for
4WD shift indicator lamp (front & rear)
LOCK indicator lamp [ON-OFF]HTransfer control unit control signal output for
4WD shift indicator lamp (center)
4LO indicator lamp [ON-OFF]HTransfer control unit control signal output for
4WD shift indicator lamp (right)
Offset at startingHAppears on monitor but does not function.
Clutch limit [N´m (kg-m, ft-lb)]HClutch force release limit value set in WORK
SUPPORT
Voltage [V]HValue measured by voltage probe is displayed.
Frequency [Hz]HValue measured by pulse probe is displayed. If
measurement is impossible, ª#º sign is dis-
played. ª#º sign is also displayed at the final
data value until the measurement result is
obtained.
DUTY-HIH
Duty cycle value for measurement probe is dis-
played.
DUTY-LOWH
PLS WIDTH-HIH
Measured pulse width of measurement probe is
displayed.
PLS WIDTH-LOWH
*: This item is indicated as ªCOMP CL TORQº.GI
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis with CONSULT-II (Cont'd)
TF-35

REFERENCE VALUE IN DATA MONITOR MODENBTF0012S09
Indicated items
(Screen terms for CONSULT, ªDATA
MONITORº mode)Display Conditions
Throttle position sensor
(THRTL POS SEN)Approx. 0.5 - 4.0V Throttle valve fully closed to fully open
Transfer fluid temperature sensor
(FLUID TEMP SE)Approx. 1.5 - 0.5VTransfer fluid temperature approx. 20 - 80ÉC (68 -
176ÉF)
Closed throttle position switch
(CLOSED THL/SW)ON After engine warm-up, accelerator pedal is released.
OFF After engine warm-up, accelerator pedal is depressed.
ABS operation switch
(ABS OPER SW)OFF ABS is not operating.
ON ABS is operating.
ABS control operation
(ABS CONT OPER)ONABS OPER SW is ªONº. Control operation is accom-
plished in combination with ABS.
OFFABS is not operating. When a message such as
ªimproper ABS operation signalº appears on the display
and ABS OPER SW is ªONº, control operation is not
accomplished in combination with ABS.
2WD position
(2WD SW)ON 4WD shift switch is in ª2WDº.
OFF Except the above condition
Lock position
(LOCK SWITCH)ON 4WD shift switch is in ª4Hº.
OFF Except the above condition
Neutral-4LO switch
(N POSI SW TF)
ATP switch
(ATP SWITCH)
Wait detection switch
(WAIT DETCT SW)4WD shift switch position2WD, AUTO,
4H(N) 4LO
ATP switch OFF ON OFF
Neutral-4LO switch OFF ON
Wait detection switchOFF ON
See Note.
Note: When shifting from ª4LOº to ª2WDº, ªAUTOº, ª4Hº, it turns ON when ªWaitº function
is operating (and it turns OFF when ªWaitº function is canceled).
Transfer motor relay
(MOTOR RELAY)Throttle valve4WD shift
switchA/T selector
leverMotor relay Remarks
Fully closed2WD Ð OFF
AUTO,
4LOP, N OFF
ON for approx. 2 sec. after
shifting to ªPº and ªNº
Others ON
4HP OFF
ON for approx. 2 sec. after
shifting to ªPº
Others ON
Line pressure switch
(LINE PRES SW)OFFThe vehicle has been left at room temperature for 5 min-
utes and more with ignition switch in ªOFFº position.
ONIgnition switch in ªONº, and 4WD shift switch in ªAUTOº
or ª4Hº and A/T selector lever in ªDº.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis with CONSULT-II (Cont'd)
TF-36

Indicated items Display Conditions
4WD-mode2WD
4WD shift switchIn ª2WDº position
AUTO In ªAUTOº position
LOCK In ª4Hº position
4L In ª4LOº position
Front wheel speed 0 - 255 km/h (0 - 158 MPH) 0 km/h (vehicle at standstill)
Rear wheel speed 0 - 255 km/h (0 - 158 MPH) 0 km/h (vehicle at standstill)
Shift ACTR operating 1,
Shift activating monitor 1OFF During normal operation
ON During shifts from ª4Hº to ª4LOº position
Shift ACTR operating 2,
Shift activating monitor 2OFF During normal operation
ON During shifts from ª4LOº to ª4Hº position
4WD fail lamp OFF During normal operation
ONDuring 2-second period (after key switch turned to ªONº) or
when system is out of order
Shift ACTR position sensing
switch 1OFF 4WD shift switch is in a position other than ª4LOº.
ON 4WD shift switch in ª4LOº position
Shift ACTR position sensing
switch 2OFF 4WD shift switch in ª4LOº position
ON 4WD shift switch is in a position other than ª4LOº.
2WD indicator lamp OFF Engine at rest or system out of order
ON Except the above condition
AUTO indicator lamp
OFFEngine at rest during 2WD-mode operation or system out of
order
ON4WD shift switch in ª4LOº or ª4Hº position and A/T selector
lever in ªAUTOº position
LOCK indicator lamp
OFFEngine at rest and A/T selector lever in ªAUTOº position during
2WD-mode operation or system out of order
ON 4WD shift switch in ª4Hº or ª4LOº position
4L indicator lamp
OFFEngine at rest and A/T selector lever in ªAUTOº position during
2WD-mode operation or system out of order
ON 4WD shift switch in ª4LOº position
WORK SUPPORTNBTF0012S06PurposeNBTF0012S0601When there is no problem with transfer and 4WD system, follow-
ing symptoms in ªAUTOº mode may be claimed by a customer.
ITight corner braking symptom after accelerator (throttle) open-
ing (Note 1)
IVibration when accelerating on a low  road (snow-covered or
icy road) (Note 2)
It is possible to deal with these symptoms by changing
ªCLUTCH FORCE RELEASE LIMIT VALUEº. However, be
careful when changing the values because it may adversely
affect driving performance.
NOTE:
1) When the accelerator is slightly open (approx. 1/8) or fully
closed after being opened. The tight corner braking symptom
during idle creep driving with accelerator fully closed cannot be
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis with CONSULT-II (Cont'd)
TF-38

SMT862D
Transfer Control Unit Terminals and Reference
Value
NBTF0018REMOVAL AND INSTALLATION OF TRANSFER
CONTROL UNIT
NBTF0018S03RemovalNBTF0018S03011. Turn ignition switch OFF and disconnect negative battery ter-
minal.
2. Remove console box.
3. Remove cluster lid C.
4. Remove audio assembly and A/C control unit.
5. Remove instrument lower panel on driver side.
6. Remove glove box.
7. Remove instrument lower panel on passenger side.
8. Remove instrument lower center panel.
9. Remove transfer control unit.
IFor steps 2 through 8 above, refer to BT-21, ªInstrument Panel
Assemblyº.
InstallationNBTF0018S0302IInstallation is in the reverse order of removal.
When installing transfer control unit, tighten transfer control unit
lock nut.
Tightening torque:
: 4.3 - 5.8 N´m (0.44 - 0.59 kg-m, 38 - 51 in-lb)
SMT771D
INSPECTION OF TRANSFER CONTROL UNITNBTF0018S01IMeasure voltage between each terminal and terminal 6 or 45
by following ªTRANSFER CONTROL UNIT INSPECTION
TABLEº, TF-55.
IPin connector terminal layout
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Transfer Control Unit Terminals and Reference Value
TF-54

2 CHECK INPUT SIGNAL
With CONSULT-II
1. Select ªECU INPUT SIGNALSº in Data Monitor.
2. Read out ON/OFF status of ª2WD SWº and ªLOCK SWITCHº.
SMT974D
OK or NG
OK©1. Perform transfer control unit input/output signal inspection. Refer to ªTRANSFER
CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL
DESCRIPTIONº, TF-55.
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with
harness connector.
NG©GO TO 3.
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2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Diagnostic Procedure (Cont'd)
TF-67