2001 INFINITI QX4 warning

2-4WD SHIFT SOLENOID VALVENBTF0067S03The 2-4WD shift solenoid valve operates to apply oil pressure to the wet, multiplate clutch, depending on the
drive mode. The driving force is transmitted to the front wheels through the clutch so the vehicle is set in the
4WD mode. Setting the vehicle in the 2WD mode requires no pressure buildup. In other words, pressure force
applied to the wet, multiplate clutch becomes zero.
LINE PRESSURE SWITCHNBTF0067S041. With the transfer system design, control of the oil pressure provides the transmission of drive torque to
the front wheels. The main pressure to control the oil pressure is referred to as the line pressure.
The line pressure switch determines whether or not adequate line pressure has built up under different
operating conditions.
2. The line pressure switch turns ON when line pressure is produced.
3. The line pressure switch senses line pressure abnormalities and turns the 4WD warning lamp ON.
ALL-MODE 4WD SYSTEM
Description of Electrical Parts (Cont'd)
TF-16

Trouble Diagnosis without CONSULT-IINBTF0011DESCRIPTIONNBTF0011S01If the engine starts when there is something wrong with the all-
mode 4WD system, the 4WD warning lamp turns ON or flickers in
the combination meter. When the system functions properly, the
warning lamp turns ON when the ignition switch is turned to ªONº,
and it turns OFF after engine starts.
To locate the cause of a problem, start the self-diagnosis function.
The 4WD warning lamp in the combination meter will indicate the
problem area by flickering according to the self-diagnostic results.
As for the details of the 4WD warning lamp flickering patterns, refer
to TF-29.GI
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Trouble Diagnosis without CONSULT-II
TF-27

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

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

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

IntroductionNBTF0013DESCRIPTIONNBTF0013S01When a malfunction (indicated by the 4WD warning lamp illumination) occurs, collect information first from the
customer about how the malfunction occurs. Then, proceed with the diagnosis presuming it is the cause. Also
inspect the electrical system, paying close attention to other possibilities such as fluid level and leaks.
All-mode 4WD transfer is controlled by transfer control unit and sensors.
If a malfunction occurs in the all-mode 4WD system, the 4WD warning lamp lights up to inform of the system
malfunction. There are two ways to identify the cause of the malfunction.
1) Performing the self-diagnosis. (The 4WD warning lamp will indicate what kind of malfunction has occurred
by flickering.)
2) Performing diagnosis using CONSULT-II.
DIAGNOSTIC WORKSHEETNBTF0013S02Information from CustomerNBTF0013S0201KEY POINTS
WHAT..... Vehicle model
WHEN..... Date, Frequencies
WHERE..... Road conditions
HOW..... Operating conditions, Symptoms
Information sheet from customer
Customer name MR/MS Model & Year VIN
Transfer model
ATX14AEngine Mileage
Incident Date Manuf. Date In Service Date
FrequencylContinuouslIntermittent ( times a day)
Symptomsl4WD shift indicator lamp does not turn on.
l4WD warning lamp does not turn on.
l4WD shift indicator lamp does not turn off.
lATP warning lamp does not turn on.
l4LO indicator lamp does not turn on.
l4WD shift indicator lamp does not indicate ª4Hº.
l4WD shift indicator lamp repeats flicking.
lTight corner braking symptom occurs.
l4WD system does not operate.
lOthers.
4WD warning lamplContinuously litlNot lit
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TROUBLE DIAGNOSIS Ð INTRODUCTION
Introduction
TF-41

2 CHECK 4WD WARNING LAMP
Is 4WD warning lamp turned ON?
SMT958D
YesorNo
Ye s©1. Turn ignition switch to ªOFFº position.
2. Perform self-diagnosis.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27.
3. Go to ª2. CHECK AT IDLEº. Refer to TF-47.
No©Go to Symptom 2. Refer to TF-100.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
TF-46

2. CHECK AT IDLE=NBTF0017S03
1 CHECK 4WD SHIFT INDICATOR LAMP
1. Park vehicle on flat surface.
2. Turn ignition switch to ªOFFº position.
3. Move A/T selector lever to ªPº or ªNº position.
4. Set 4WD shift switch to ª4Hº position.
5. Set 4WD shift switch to ª2WDº position.
6. Start engine.
7. Is 4WD shift indicator lamp turned OFF?
SMT958D
YesorNo
Ye s©Go to ªATP SWITCH, WAIT DETECTION SWITCH AND NEUTRAL-4LO SWITCHº. Refer
to TF-76.
No©GO TO 2.
2 CHECK 4WD WARNING LAMP
Is 4WD warning lamp turned OFF?
YesorNo
Ye s©GO TO 3.
No©Perform self-diagnosis. Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
TF-47