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Infiniti QX4 (R50). Manual - part 573

SMT862D

Transfer Control Unit Terminals and Reference
Value

NBTF0018

REMOVAL AND INSTALLATION OF TRANSFER
CONTROL UNIT

NBTF0018S03

Removal

NBTF0018S0301

Turn ignition switch OFF and disconnect negative battery ter-
minal.

Remove console box.

Remove cluster lid C.

Remove audio assembly and A/C control unit.

Remove instrument lower panel on driver side.

Remove glove box.

Remove instrument lower panel on passenger side.

Remove instrument lower center panel.

Remove transfer control unit.

For steps 2 through 8 above, refer to BT-21, “Instrument Panel
Assembly”.

Installation

NBTF0018S0302

Installation 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 UNIT

NBTF0018S01

Measure voltage between each terminal and terminal 6 or 45
by following “TRANSFER CONTROL UNIT INSPECTION
TABLE”, TF-55.

Pin connector terminal layout

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION

Transfer Control Unit Terminals and Reference Value

TF-54

SMT772D

TRANSFER CONTROL UNIT INSPECTION TABLE

NBTF0018S02

(Data are reference values.)

Terminal

No.

Item

Condition

Judgement standard

2-4WD shift solenoid
valve

4WD shift switch is set to “2WD”
position.

Less than 1V

4WD shift switch is set to any posi-
tion other than “2WD”.

Battery voltage

4WD shift indicator lamp
(2WD)

Lamp lights while system is operating
properly.

Less than 1V

2WD indicator lamp does not come
on.

Battery voltage

Ground

—

Transfer shift relay
(High)

While actuator is operating
(4H

4LO)

Battery voltage

Actuator does not operate.

Less than 1V

4WD warning lamp

Lamp 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

Ground

—

PNP switch (R position)

A/T selector lever is set to “reverse”
position.

Battery voltage

A/T selector lever is set to any posi-
tion other than “reverse”.

Less than 1V

—

IDX

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION

Transfer Control Unit Terminals and Reference Value (Cont’d)

TF-55

Terminal

No.

Item

Condition

Judgement standard

4WD shift switch (2WD)

4WD shift switch is set to “2WD”
position.

Battery voltage

4WD shift switch is set to any posi-
tion other than “2WD”.

Less than 1V

Transfer dropping resis-
tor

4WD shift switch is set to “AUTO”
position.

Approx. 4 - 14V

4WD shift switch is set to any posi-
tion other than “2WD”.

Less than 1V

4WD shift indicator lamp
(4H)

“4H” indicator lamp comes ON.

Less than 1V

4WD shift switch is set to any posi-
tion other than “4H”.

Battery voltage

4WD shift indicator lamp
(4LO)

“4LO” indicator lamp comes ON.

Approx. 0V

4WD shift switch is set to any posi-
tion other than “4LO”.

Battery voltage

Transfer shift relay (Low)

While actuator is operating
(4LO

4H)

Battery voltage

Actuator does not operate.

Approx. 0V

Transfer motor relay

Transfer motor relay is ON.

Battery voltage

Transfer motor relay is OFF.

Less than 1V

PNP switch (N position)

A/T selector lever is set to “N” posi-
tion.

Battery voltage

A/T selector lever is set to any posi-
tion other than “N” position.

Less than 1V

Power supply

—

Ignition key is set to “ON” position.

Battery voltage

Ignition key is set to “OFF” position.

Approx. 0V

PNP switch (P position)

A/T selector lever is set to “P” posi-
tion.

Battery voltage

A/T selector lever is set to any posi-
tion other than “P”.

Less than 1V

4WD shift switch (4H)

4WD shift switch is set to “4H” posi-
tion.

Battery voltage

4WD shift switch is set to any posi-
tion other than “4H”.

Less than 1V

4WD solenoid valve

4WD shift switch is set to “AUTO”
position.

Approx. 1.5 - 3V

4WD shift switch is set to any posi-
tion other than “2WD”.

Less than 1V

—

4WD shift indicator lamp
(AUTO)

“AUTO” indicator lamp comes ON.

Approx. 0V

4WD shift switch is set to any posi-
tion other than “AUTO”.

Battery voltage

Power supply

—

Ignition key is set to “ON” position.

Battery voltage

Ignition key is set to “OFF” position.

Approx. 0V

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION

Transfer Control Unit Terminals and Reference Value (Cont’d)

TF-56

Terminal

No.

Item

Condition

Judgement standard

4WD shift switch (4LO)

4WD shift switch is set to “4LO” posi-
tion.

Battery voltage

4WD shift switch is set to any posi-
tion other than “4LO”.

Less than 1V

4WD shift switch (AUTO)

4WD shift switch is set to “AUTO”
position.

Battery voltage

4WD shift switch is set to any posi-
tion other than “AUTO”.

Less than 1V

Neutral-4LO switch

Transfer is set to “4LO” position.

Approx. 0V

Transfer is set to any position other
than “4LO”.

Power supply

Throttle position switch
(closed)

Throttle valve is closed.

Power supply

Throttle valve is in any position other
than “closed”.

Approx. 0V

Transfer 4H actuator
switch

4WD shift switch is set to “4H” posi-
tion.

Less than 1V

4WD shift switch is set to any posi-
tion other than “4H”.

Battery voltage

Throttle position sensor
(Ground)

Throttle valve is closed.

Less than 1V

Throttle valve is fully open.

TCM 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

Throttle position sensor
(Power supply for throttle
position sensor)

Ignition key is set to “ON” position.

Approx. 4.5 - 5.5V

Ignition key is set to “OFF” position.

Approx. 0V

IDX

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION

Transfer Control Unit Terminals and Reference Value (Cont’d)

TF-57

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