2001 INFINITI QX4 02 sensor

CONTROL SYSTEM DIAGRAMNBTF0007S04
SMT763D
INDICATIONS OF 4WD WARNING LAMPNBTF0007S05
Condition Content 4WD warning lamp
During self-diagnosis Indicates the malfunction position by number of flickers. Flickers at malfunction mode.
Lamp check*Checks the lamp by turning ON during engine starting. After
engine starts, it turns OFF if there are no malfunctions.ON
Malfunction in 4WD system*Turns ON to indicate malfunction. When ignition switch is
turned to ªOFFº or the malfunction is corrected, it turns OFF.ON
When vehicle is driven with different
diameters of front and rear tiresFlickers once every 2 seconds.
Turns OFF when ignition switch is ªOFFº.Flickers once every 2 sec-
onds.
High fluid temperature in transfer
unitWhen fluid temperature is high or fluid temperature sensor
circuit is shorted, it flickers twice every second.
It turns OFF when fluid temperature becomes normal.Flickers twice a second.
Other than above (System is nor-
mal.)Lamp is OFF. OFF
*: When 4WD warning lamp is ON, all the 4WD shift indicator lamps turn OFF.
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ALL-MODE 4WD SYSTEM
Control System (Cont'd)
TF-13

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

INDICATIONS OF 4WD WARNING LAMPNBTF0011S03
Flickering pattern or flick-
ering conditionMalfunction Check items
1 Front revolution sensor circuit is shorted or open.Revolution sensor (front) circuit,
TF-61.
2 Rear revolution sensor circuit is shorted or open.Revolution sensor (rear) [Refer to
AT-111, ªDTC P0720 Vehicle Speed
Sensor´A/T (Revolution sensor)º.]
3 4WD solenoid valve circuit is shorted or open. 4WD solenoid valve circuit, TF-64.
42-4WD shift solenoid valve circuit is shorted or 2WD switch of
4WD shift switch is shorted.2-4WD shift solenoid valve circuit or
4WD shift switch circuit, TF-66.
5 Transfer motor relay circuit is shorted or open. Transfer motor relay circuit, TF-70.
8Power supply voltage of throttle position sensor is improper. Or
A/D converter of transfer control unit functions improperly.Throttle position sensor (Refer to
AT-176, ªDTC P1705 Throttle Posi-
tion Sensorº.)
9 Transfer fluid temperature sensor circuit is open.Transfer fluid temperature sensor
circuit, TF-73.
10 Neutral-4LO switch circuit is shorted or open. Neutral-4LO switch circuit, TF-76.
112-4WD shift solenoid valve circuit, 2WD switch of 4WD shift
switch circuit or clutch pressure switch circuit is shorted or open.2-4WD shift solenoid valve circuit,
4WD shift switch circuit or clutch
pressure switch circuit, TF-66, 80.
12 Line pressure switch circuit is shorted or open. Line pressure switch circuit, TF-83.
13 Engine speed signal circuit is shorted or open.Engine speed signal (Refer to
AT-116, ªDTC P0725 Engine Speed
Signalº.)
14 Throttle position sensor circuit is shorted or open.Throttle position sensor (Refer to
AT-176, ªDTC P1705 Throttle Posi-
tion Sensorº.)
15 Failure in power supply circuit of transfer control unit. Power supply of transfer control unit
16 4WD shift switch circuit is shorted. 4WD shift switch circuit, TF-66.
17 ABS operation signal circuit is shorted. ABS operation signal circuit, TF-86.
18ATP switch, wait detection switch or neutral-4LO switch circuit is
shorted or open.ATP switch, wait detection switch or
neutral-4LO switch circuit*, TF-76.
19Transfer control device actuator motor is faulty. (Abnormalities
are detected when actuator motor fails to operate while shifting
from ª4Hº to ª4LOº or vice versa.)Actuator motor and motor circuit,
TF-115, 89.
20Transfer control device actuator motor arm position sensing
switch is faulty.Actuator motor arm position sensing
switch and sensing switch circuit,
TF-115, 92.
21Transfer control device actuator circuit is faulty (Abnormalities
are detected when motor relay circuit is open/shorted or relay
monitor circuit is open/shorted.)Actuator motor, actuator motor arm
position sensing switch and their
associated circuits, TF-114, 115 and
94.
Repeats flickering every
2 to 5 sec.Circuits that the self-diagnosis covers have no malfunction. Ð
Repeats flickering every
0.25 sec.IPower supply failure of memory back-up.
IBattery is disconnected for a long time.
IBattery performance is poor.Data erase/display circuit, TF-88.GI
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis without CONSULT-II (Cont'd)
TF-29

Flickering pattern or flick-
ering conditionMalfunction Check items
No flickering PNP switch or 4WD shift switch circuit is shorted or open.PNP switch (Refer to AT-99, ªDTC
P0705 Park/Neutral Position
Switchº.) or 4WD shift switch circuit,
TF-66.
*: If revolution sensor malfunction is simultaneously detected, check revolution sensor first.
SAT601J
Trouble Diagnosis with CONSULT-IINBTF0012SELF-DIAGNOSISNBTF0012S01CONSULT-II Setting ProcedureNBTF0012S01011. Turn ignition switch to ªOFFº position.
SMT962D
2. Connect CONSULT-II to data link connector which is located
in instrument lower panel on driver side.
SAT586J
3. Start engine.
4. On CONSULT-II screen, touch ªSTARTº.
SMT964D
5. Touch ªALL MODE 4WDº on SELECT SYSTEM screen.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis without CONSULT-II (Cont'd)
TF-30

SMT965D
6. Touch ªSELF-DIAG RESULTSº on SELECT DIAG MODE
screen.
SMT966D
7. Self-diagnostic results are displayed.
SELF-DIAGNOSTIC ITEMSNBTF0012S02
Detected items
(Screen terms for CONSULT-II,
ªSELF-DIAG RESULTº mode)Malfunction is detected when... Check items
Revolution sensor (front) (Note 3)
(VHCL SPEED SEN´FR)IFront revolution sensor (installed on T/F) signal is not
input due to open circuit.
IImproper signal is input while driving.Revolution sensor (front) circuit,
TF-61.
Revolution sensor (rear)
(VHCL SPEED SEN´RR)ISignal from vehicle speed sensor 1 (installed on A/T)
is not input due to open circuit.
IImproper signal is input while driving.Revolution sensor (rear) [Refer to
AT-111, ªDTC P0720 Vehicle Speed
Sensor´A/T (Revolution sensor)º.]
4WD solenoid valve
(DUTY SOLENOID)
IProper voltage is not applied to solenoid valve due to
open or short circuit.4WD solenoid valve, TF-64.
2-4WD shift solenoid valve
(2-4WD SOLENOID)2-4WD shift solenoid valve or
4WD shift switch circuit, TF-66.
Transfer motor relay
(MOTOR RELAY)IMotor does not operate properly due to open or short
circuit in transfer motor or motor relay.Transfer motor relay circuit,
TF-70.
Transfer fluid temperature sensor
(FLUID TEMP SENSOR)ISignal voltage from fluid temperature sensor is abnor-
mally high (T/F fluid temperature is abnormally low)
while driving.Transfer fluid temperature sensor
circuit, TF-73.
Neutral-4LO switch
(N POSI SW TF)IImproper signal is input while driving. Neutral-4LO switch, TF-76.
Clutch pressure
(CLUTCH PRESSURE)IImproper signal is input due to open or short circuit.
IMalfunction occurs in clutch pressure hydraulic circuit.Clutch pressure switch circuit
(*1), TF-80.
Line pressure
(LINE PRESSURE)IImproper signal is input due to open or short circuit.
IMalfunction occurs in line pressure hydraulic circuit.Line pressure switch circuit (*1),
TF-83.
Engine speed signal (Note 1)
(ENGINE SPEED SIG)IEngine speed is abnormally low while driving.Engine speed signal (Refer to
AT-116, ªDTC P0725 Engine Speed
Signalº.)
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis with CONSULT-II (Cont'd)
TF-31

Detected items
(Screen terms for CONSULT-II,
ªSELF-DIAG RESULTº mode)Malfunction is detected when... Check items
Throttle position sensor
(THRTL POSI SEN)ISignal voltage from throttle position sensor is abnor-
mally high.
ISignal voltage from throttle position sensor is abnor-
mally low when closed throttle position switch is OFF.Throttle position sensor (Refer to
AT-176, ªDTC P1705 Throttle
Position Sensorº.)
Transfer control unit (ADC)
C/U (ADC)/THRTL SENIPower supply voltage for throttle position sensor is
improper or A/D converter system of transfer control
unit is faulty.Throttle position sensor (Refer to
AT-176, ªDTC P1705 Throttle
Position Sensorº.)
Battery voltage (Note 1)
(BATTERY VOLTAGE)IPower supply voltage for transfer control unit is abnor-
mally low while driving.Power supply circuit (Refer to
AT-96, ªWiring Diagram Ð AT Ð
MAINº.)
4WD shift switch
(4WD MODE SW)IMore than two switch inputs are simultaneously
detected due to short circuit of 4WD shift switch.4WD shift switch circuit, TF-66.
ABS operation signal (Note 4)
(ABS OPER SIGNAL)IWhen a malfunction signal due to disconnection or
shorting is detected.
IWhen a defect signal is entered from the ABS control
unit.ABS operation signal circuit,
TF-86.
Wait detection switch (Note 2)
(WAIT DETECT SWITCH)IImproper signal is input due to open or short circuit.ATP switch, wait detection switch
and neutral-4LO switch circuits
(*2), TF-76.
Shift actuator abnormal
(SHIFT ACT)Transfer control device actuator motor is faulty. (Abnor-
malities are detected when actuator motor fails to oper-
ate while shifting from ª4Hº to ª4LOº or vice versa.)Actuator motor and motor circuit,
TF-115, 89.
Shift actuator position switch
abnormal
(SHIFT ACT P/S)Transfer control device actuator motor arm position sens-
ing switch is faulty.Actuator motor arm position
sensing switch and sensing
switch circuit, TF-115, 92.
Shift actuator circuit abnormal
(SHIFT ACT CIR)Transfer control device actuator circuit is faulty (Abnor-
malities are detected when motor relay circuit is open/
shorted or relay monitor circuit is open/shorted.)Actuator motor, actuator motor
arm position sensing switch and
their associated circuits, TF-114,
115 and 94.
Memory power supply stopIDue to removal of battery which cuts off power supply
to transfer control unit, self-diagnosis memory function
is suspended.Data erase/display circuit, TF-88.
Transfer control unit (RAM)
[CONTROL UNIT (RAM)]IFailure is detected in the memory (RAM) system of
transfer control unit.
Transfer control unit (ROM)
[CONTROL UNIT (ROM)]IFailure is detected in the memory (ROM) system of
transfer control unit.
Transfer control unit (EEPROM)
[CONTROL UNIT (EEPROM)]IFailure is detected in the memory (EEPROM) system
of transfer control unit.
Note 1: When a malfunction occurs, it is only displayed and not stored in the memory.
Note 2: When the wait detection switch has been properly fixed, malfunction information is erased from the memory.
Note 3: If 4WD shift switch is left between 4H and 4LO for a while, this indication may be displayed.
(*1): If the malfunction is detected only while driving in reverse, check the continuity of ªRº position on A/T PNP switch. When there is
nothing wrong with the electrical system, check the hydraulic system.
(*2): If a revolution sensor malfunction is detected at the same time, check the revolution sensor circuit first.
Note 4: When this malfunction is detected with the ABS warning lamp off, first check for disconnection or shorting in the harness between
the transfer control unit and the ABS control unit.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis with CONSULT-II (Cont'd)
TF-32

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

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