2001 INFINITI QX4 4WD

5 CONFIRM SYMPTOM AGAIN
Confirm symptom and self-diagnosis again.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27 and ªTrouble Diagnosis with CONSULT-IIº, TF-30.
OK or NG
OK©GO TO 6.
NG©Go to Symptoms 8 and 9. Refer to TF-108, 109.
6 (2) CHECK TIGHT CORNER BRAKING SYMPTOM
1. Set 4WD shift switch to ª4Hº position.
2. Drive vehicle at speed lower than 20 km/h (12 MPH) with steering wheel fully turned.
3. Does tight corner braking symptom occur?
YesorNo
Ye s©INSPECTION END
No©GO TO 7.
7 CONFIRM SYMPTOM AGAIN
Confirm symptom and self-diagnosis again.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27 and ªTrouble Diagnosis with CONSULT-IIº, TF-30.
OK or NG
OK©INSPECTION END
NG©Go to Symptoms 8 and 9. Refer to TF-108, 109.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
TF-53

SMT772D
TRANSFER CONTROL UNIT INSPECTION TABLENBTF0018S02(Data are reference values.)
Terminal
No.Item Condition Judgement standard
12-4WD shift solenoid
valve
&
4WD shift switch is set to ª2WDº
position.Less than 1V
4WD shift switch is set to any posi-
tion other than ª2WDº.Battery voltage
24WD shift indicator lamp
(2WD)
Lamp lights while system is operating
properly.Less than 1V
&
2WD indicator lamp does not come
on.Battery voltage
3 Ground Ð Ð
4Transfer shift relay
(High)While actuator is operating
(4H,4LO)Battery voltage
Actuator does not operate. Less than 1V
5 4WD warning lampLamp comes ON. (when engine is
stopped.)
(Fail-safe condition appears on
display, engine is stopped, actuator
position detection switch is
inoperative, oil temperature is too
high and/or tires of different size are
installed.)Less than 1V
Except above Battery voltage
6 Ground Ð Ð Ð
7 PNP switch (R position)
&
A/T selector lever is set to ªreverseº
position.Battery voltage
A/T selector lever is set to any posi-
tion other than ªreverseº.Less than 1V
8ÐÐÐÐ
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Transfer Control Unit Terminals and Reference Value (Cont'd)
TF-55

Terminal
No.Item Condition Judgement standard
9 4WD shift switch (2WD)
&
4WD shift switch is set to ª2WDº
position.Battery voltage
4WD shift switch is set to any posi-
tion other than ª2WDº.Less than 1V
10Transfer dropping resis-
tor4WD shift switch is set to ªAUTOº
position.Approx.4-14V
4WD shift switch is set to any posi-
tion other than ª2WDº.Less than 1V
114WD shift indicator lamp
(4H)
ª4Hº indicator lamp comes ON. Less than 1V
4WD shift switch is set to any posi-
tion other than ª4Hº.Battery voltage
124WD shift indicator lamp
(4LO)ª4LOº indicator lamp comes ON. Approx. 0V
4WD shift switch is set to any posi-
tion other than ª4LOº.Battery voltage
13 Transfer shift relay (Low)
&
While actuator is operating
(4LO,4H)Battery voltage
Actuator does not operate. Approx. 0V
14 Transfer motor relayTransfer motor relay is ON. Battery voltage
Transfer motor relay is OFF. Less than 1V
15 PNP switch (N position)A/T selector lever is set to ªNº posi-
tion.Battery voltage
A/T selector lever is set to any posi-
tion other than ªNº position.Less than 1V
16 Power supply ÐIgnition key is set to ªONº position. Battery voltage
Ignition key is set to ªOFFº position. Approx. 0V
17 PNP switch (P position)
&
A/T selector lever is set to ªPº posi-
tion.Battery voltage
A/T selector lever is set to any posi-
tion other than ªPº.Less than 1V
18 4WD shift switch (4H)4WD shift switch is set to ª4Hº posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than ª4Hº.Less than 1V
19 4WD solenoid valve4WD shift switch is set to ªAUTOº
position.Approx. 1.5 - 3V
4WD shift switch is set to any posi-
tion other than ª2WDº.Less than 1V
20ÐÐÐÐ
214WD shift indicator lamp
(AUTO)
ªAUTOº indicator lamp comes ON. Approx. 0V
4WD shift switch is set to any posi-
tion other than ªAUTOº.Battery voltage
22 Power supply ÐIgnition key is set to ªONº position. Battery voltage
Ignition key is set to ªOFFº position. Approx. 0V
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Transfer Control Unit Terminals and Reference Value (Cont'd)
TF-56

Terminal
No.Item Condition Judgement standard
23 4WD shift switch (4LO)
&
4WD shift switch is set to ª4LOº posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than ª4LOº.Less than 1V
24 4WD shift switch (AUTO)4WD shift switch is set to ªAUTOº
position.Battery voltage
4WD shift switch is set to any posi-
tion other than ªAUTOº.Less than 1V
25 Neutral-4LO switchTransfer is set to ª4LOº position. Approx. 0V
Transfer is set to any position other
than ª4LOº.Power supply
26Throttle position switch
(closed)Throttle valve is closed. Power supply
Throttle valve is in any position other
than ªclosedº.Approx. 0V
27Transfer 4H actuator
switch4WD shift switch is set to ª4Hº posi-
tion.Less than 1V
4WD shift switch is set to any posi-
tion other than ª4Hº.Battery voltage
28Throttle position sensor
(Ground)Throttle valve is closed.
Less than 1V
Throttle valve is fully open.
29TCM signal (Vehicle
speed signal)When moving at 20 km/h (12 MPH),
use the CONSULT-II pulse frequency
measuring function.*1
CAUTION:
Connect the diagnosis data link
cable to the vehicle diagnosis con-
nector.
*1: A circuit tester cannot be used to
test this item.Approximately 225 Hz
30Throttle position sensor
(Power supply for throttle
position sensor)Ignition key is set to ªONº position. Approx. 4.5 - 5.5V
Ignition key is set to ªOFFº position. Approx. 0VGI
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Transfer Control Unit Terminals and Reference Value (Cont'd)
TF-57

Terminal
No.Item Condition Judgement standard
31Transfer fluid tempera-
ture sensor
&
At 20ÉC (68ÉF) Approx. 1.5V
At 80ÉC (176ÉF) Approx. 0.5V
32 ABS signalWhen moving, use the CONSULT-II
pulse frequency measuirng func-
tion.*2
CAUTION:
Connect the diagnosis data link
cable to the vehicle diagnosis con-
nector.
*2: A circuit tester cannot be used to
test this item.Refer to the illustration
(SMT973D) at the end of
this section.
33Transfer shift relay
(High)While actuator is operating from ª4Hº
to ª4LOºBattery voltage
Actuator does not operate. Approx. 0V
34 Clutch pressure switch4WD shift switch is set to ªAUTOº or
ª4Hº, then A/T selector lever is set to
ªDº position. (wait detection system:
OFF)Battery voltage
4WD shift switch is set to ª2WDº,
ªAUTOº or ª4Hº, then A/T selector
lever is set to ªDº position. (wait
detection system: ON)Approx. 0V
35 Line pressure switch4WD shift switch is set to ª2WDº,
ªAUTOº or ª4Hº, then A/T selector
lever is set to ªDº position.Battery voltage
Ð Approx. 0V
36 CONSULT-II (RX) Ð Ð Ð
37 Tachometer
ÐRefer to EC-127, ªECM
Inspection Tableº.
38 Front revolution sensor
4WD shift switch is set to ª4Hº posi-
tion. A/T selector lever is set to ªDº
position.Approx. 1V [30 km/h (19
MPH)]
Voltage rises in
response to vehicle
speed.
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Transfer Control Unit Terminals and Reference Value (Cont'd)
TF-58

Terminal
No.Item Condition Judgement standard
39ECM (Throttle position
sensor)
&
Throttle valve is fully open. Approx. 0.5V
Throttle valve is closed. Approx. 4.2V
40 ATP switchA/T selector lever is set to ªPº posi-
tion.Battery voltage
A/T selector lever is set to any posi-
tion other than ªPº.Less than 1V
41Transfer motor relay
monitorTransfer motor relay is ON. Battery voltage
Transfer motor relay is OFF. Less than 1V
42Transfer shift relay
(LOW)While actuator is operating from
ª4LOº to ª4Hº positionBattery voltage
Actuator does not operate. Approx. 0V
43 Wait detection switch4WD shift switch is set to any posi-
tion other than ª4LOº.Battery voltage
4WD shift switch is set to ª4LOº posi-
tion.*3Less than 1V
44Transfer 4LO actuator
switch4WD shift switch is set to any posi-
tion other than ª4LOº. (Actuator: High
position)Battery voltage
4WD shift switch is set to ª4LOº posi-
tion. (Actuator: Low position)Less than 1V
45 Ground Ð Ð Ð
46ÐÐÐÐ
47Power supply (memory
back up)
&Ð Battery voltage
48 CONSULT-II (TX) Ð Ð Ð
*3: While wait detection system is operating, terminal 43 exists battery voltage.
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Transfer Control Unit Terminals and Reference Value (Cont'd)
TF-59

Diagnostic ProcedureNBTF0020
1 CHECK 4WD SOLENOID VALVE
SMT775D
Refer to ª4WD Solenoid Valve, Clutch Pressure Switch and Line Pressure Switchº, ªCOMPONENT INSPECTIONº, TF-111.
OK or NG
OK©GO TO 2.
NG©Check the following. If OK, repair or replace 4WD solenoid valve.
IContinuity of transfer sub-harness
Refer to ªTRANSFER TERMINAL CORD ASSEMBLY SUB-HARNESS CONNECTORº,
ªCOMPONENT INSPECTIONº, TF-114.
2 CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to ªOFFº position.
2. Disconnect transfer control unit harness connector.
3. Check resistance between transfer terminal cord assembly sub-harness connector terminal 6 and transfer control unit
harness connector terminal 10.
Resistance: 11.2 - 12.8W
SMT776D
OK or NG
OK©GO TO 3.
NG©Check the following.
ITransfer dropping resistor
Refer to ªTransfer Dropping Resistorº, ªCOMPONENT INSPECTIONº, TF-112.
IContinuity between transfer terminal cord assembly sub-harness connector terminal 6
and transfer control unit harness connector terminal 10.
4WD SOLENOID VALVE
Diagnostic Procedure
TF-64

3 CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to ªOFFº position.
2. Check continuity between transfer terminal cord assembly sub-harness connector terminal 6 and transfer control unit
harness connector terminal 19.
Continuity should exist.
SMT777D
OK or NG
OK©GO TO 4.
NG©Repair or replace harness between transfer terminal cord assembly sub-harness connec-
tor terminal 6 and transfer control unit harness connector terminal 19.
4 PERFORM SELF-DIAGNOSIS
After driving for a while, perform self-diagnosis.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27 and ªTrouble Diagnosis with CONSULT-IIº, TF-30.
OK or NG
OK©INSPECTION END
NG©1. Perform transfer control unit input/output signal inspection. Refer to ªTRANSFER
CONTROL UNIT INSPECTION TABLEº, TF-55.
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with
harness connector.
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4WD SOLENOID VALVE
Diagnostic Procedure (Cont'd)
TF-65