2004 ISUZU TF SERIES engine

TRANSFER CONTROL SYSTEM 7D1-33

No. Connector face No. Connector face
P-2
Silver
Relay & Fuse box


P-5
Silver
Battery (-)


P-6
Silver
Body earth (Ground)


P-10
Silver
Engine ground


P-13
(4JH1)
Gray
Shift on the fly actuator


R-14

Black 2-4WD Control unit


R-15

Black 2-4WD Control unit

TRANSFER CONTROL SYSTEM 7D1-35
3.
Shifting from 4H to 4L
3-1 When the 4L indicator flashes at 2Hz
When shifting from 4H to 4L, the 4L indicator continues flashing at 2Hz until shifting in the transfer case is
completed. The phases of the engaged splines may sometimes deviated preventing completion of shifting.
By correcting the deviation of phases, shifting is completed.

Step 3-1:
(In case of AT): Set the select bar of the transmission to the D position.
(In case of MT): Set the lever of the transmission to a position allowing running and engage the clutch
gently.
At this time, some rotating force acts on the engaged splines, phase is corrected and the engagement is
completed.

3-2 When the 4L indicator flashes at 2Hz for 10 seconds and then keeps ON again (AT vehicle)
This condition occurs when torsional torque has been generated between the transmission and road surface
and the transfer standby mechanism cannot absorb it completely.

Step 3-2:
Set the select lever of the transmission to the N position. (Stepping on the brake pedal is effective at
this time.)

3-3 When the 4L indicator flashes at a frequency of 4Hz
Shifting from 4H to 4L is restricted.
When the vehicle is running, the transmission lever is at the running range and the engine speed is high (L4:
3000rpm or more V6: 2000rpm), the transfer cannot be shifted from 4H to 4L (restriction on operation).

Restriction on operation (Except 4JA1-LT)
The 4H, neutral and 4L shifting mechanism has no synchronization function. Therefore, if relative rotations in the
mechanism become excessive, shifting exerts adverse influence on the internal mechanism of the transfer. To
avoid such a trouble, vehicle condition is detected to restrict the operation (vehicle speed, engine speed and TM
position).
Requirement to restrict the speed: Vehicle should be in stop.
For the reason of the detection logic, time to wait for start of operation may be required.
A/T: If the vehicle is in stop for a long time at the TM running range (D, 1, 2) before operating the AT, waiting
time becomes longer (from 1 second to 3 minutes at the maximum).
M/T: If the vehicle is at stop with the clutch stepped on at the T/M running position (1 – R), the time to wait
becomes longer.
Waiting time means the time commencing from when other requirements (engine speed and T/M position) are
met to permission of the speed restriction. Operation during the waiting time is not permissible.
The waiting time is 1 second at the minimum and increases up to 5 seconds if the above condition continues 3
minutes. After that, the waiting time increases up to 3 minutes in 2 minutes.
When it is clear that the above condition has continued and reduction of waiting time is desirable, turn on or off
the ignition or start and stop the vehicle several meters.
Requirements for permission of restriction on engine speed: Engine speed should be decreased.
The engine speed of 3000rpm (V6: 2000rpm) or below is advisable.
Requirements for permission of restriction on T/M position restriction:
(AT) N range is recommendable
(MT) should be at the neutral.

These requirements for permission should be all met before the switch is operated. If the requirements are met
after operation, operation is not automatically effected but re-operation is required after permission is given.

7D1-36 TRANSFER CONTROL SYSTEM
Restriction on operation (4JA1-LT)
The 4H, neutral and 4L shifting mechanism has no synchronization function. Therefore, if relative rotations in the
mechanism become excessive, shifting exerts adverse influence on the internal mechanism of the transfer. To
avoid such a trouble, vehicle condition is detected to restrict the operation (vehicle speed, and TM position).
Requirement to restrict the speed: Vehicle should be in stop.
Requirements for permission of restriction on engine speed: Engine speed should be decreased.
The engine speed of 3000rpm (V6: 2000rpm) or below is advisable.
Requirements for permission of restriction on T/M position restriction:
should be at the neutral.

These requirements for permission should be all met before the switch is operated. If the requirements are met
after operation, operation is not automatically effected but re-operation is required after permission is given.

Note: Don’t’ accelerate engine speed a the time of this operation.

Step 3-3:
Stop the vehicle. (Close the accelerator and decrease the engine speed to below L4: 3000rpm, V6:
2000rpm.)
(In case of AT): Set the transmission select lever to the N position.
(In case of MT): Set the transmission lever to the neutral position. (Stepping on the clutch is
recommendable.) Push the 4L button.
If shifting operation is not completed (the lamp flashes at 2Hz), perform the step 3-1.

4. Shifting from 4L to 4H
4-1 When 4L indicator continues flashing at 2HZ
When shifting from 4L to 4H, the 4L indicator continues flashing at 2Hz until the shifting in the transfer case is
completed. Phases of engaged splines may deviate and the operation may not completed in some cases.
Shifting is completed by correcting the deviation of the splines.

Step 4-1: (same as step 3-1)
(In case of AT): Set the transmission select lever to the D position.
(In case of MT): Shift the transmission lever to a position allowing running and engage the clutch
gently.

4-2 When the indicator continues flashing at 2Hz for 10 seconds and then keeps on at 4L again (AT
vehicle)
This condition occurs when torsional torque has generated between the transmission and the road surface
(use of the parking position on a slope) and resistance against the separation of the driving force cannot be
fully by the waiting mechanism of the transfer.
Shifting is possible by using the brake also at the neutral position of the transmission

Step 4-2: (Same procedure
as the step 3-2)
Set the transmission select lever to the N position.
(Leaving the brake lever and stepping it again is recommendable.)

4-3 When the 4L indicator flashes at 4HZ
Shifting from 4L to 4H is restricted.
When the vehicle is running, transmission lever is at the running range, and the engine speed is high, the
transfer 4L cannot be shifted to 4H.

TRANSFER CONTROL SYSTEM 7D1-37
Step 4-3: (Same procedure as the step 3-3)
Stop the vehicle (close the accelerator and decrease the engine speed to L4: 3000rpm V6: 2000rpm or
below).
(In case of AT): Set the transmission select lever to the N position.
(In case of MT): Set the transmission lever to the neutral position (stepping on the clutch lever is
recommendable).
Push the 4H button.
If the shifting is not completed (indicator flashes at 2Hz), go to the step 4-1.

5. When shifting from 4H or 4L to neutral
(Same procedure is required when shifting from 2H but in such a case, requirements for shifting from
2H to 4H are also applied.)
5-1 Neutral indicator continues flashing at 2Hz
The neutral indicator continues flashing at 2Hz until 4H (4L) is completely separated in the transfer. If
torsional torque has accumulated between the transmission and road surface, separation may be difficult.

Step 5-1:
If the operation is not completed, execute the step 7 for confirmation.
(In case of AT): Set the transmission select lever to the D position.
After confirming that the gears are at the neutral position, return the lever to the N
position.
(In case of MT): Set the transmission lever to a vehicle running position and engage the clutch gently.
After confirming that the gears are at the neutral position, return the lever to the
neutral position

5-2 When the neutral indicator flashes at 4Hz
As in the case of shifting from 4L to 4H, restriction is imposed to the operation from 4L or 4H (including 2H).
If the transmission lever is at a running range and engine speed is high (L4: 3000rpm, V6: 2000rpm or more)
while the vehicle is running, operation from the 4L or 4H (including 2H) of the transfer to the neutral is
impossible (restriction on operation).

Step 5-2:
Stop the vehicle.
(In case of AT): Set the transmission select lever to the N (or P) position.
(In case of MT): Set the transmission lever to the neutral position (at this time, stepping on the clutch
is recommended).
Keep pushing the 2H and 4L button for 10 second.
Follow the start procedure for confirmation. (Confirmation of drive force not transferred; same as in the
step 5-1)
After the confirmation, set the transmission to the neutral position in case of MT or to the neutral
position in case of AT.

7D1-38 TRANSFER CONTROL SYSTEM
6. When shifting from neutral to 2H, 4H or 4L
6-1 When the 4L indicator or 4WD indicator flashes at 2Hz
Indicator flashing at 2Hz indicates that the engagement of the splines has not completed because of
deviation of the spline phases. By eliminating such a deviation, shifting is completed (same as in the step 3-1
and 4-1).
6-2 When the 4L indicator or 4WD indicator flashes at 4Hz
As in the case of shifting from 4L to 4H, restriction is imposed to the operation to 4L or 4H (including 2H). If
the transmission lever is at a running range and engine speed is high (3000rpm or more) while the vehicle is
running, operation from neutral of the transfer to the 4L or 4H (including 2H) is impossible (restriction on
operation).

Step 6-2:
Stop the vehicle.
(In case of AT): Set the transmission select lever to the N (or P) position.
(In case of MT): Set the transmission lever to the neutral position (at this time, stepping on the clutch
is recommended).
Keep pushing the4H or 4L or 2H button for 10 second.

7D1-48 TRANSFER CONTROL SYSTEM
From 4H to 4L; Even after the correction step 3-3(*), 4Lo indicator blinks at 4Hz
Step Action Yes No
1 Is the ignition switch ON? Turn it OFF once. Go to step 2.
2 Turn ON the ignition switch and
check the valve. Do not start
the engine.
Has the valve check for 2
seconds been completed
normally? Go to step 3. Refer to the paragraph about the
indicator when it does not react
when shifted from 2H to 4H.
After taking the remedy, trace
this chart from the beginning.
3 Shift to 2H.
Can be shifted to 2H and then to
4H? Go to step 4. Refer to the paragraph about
shifting from 2H to 4H.
In particular, check if not at the
Check4WD condition, return to
this chart and trace it from the
beginning.
4 Set to N position in case of AT
and set to the neutral position in
case of MT and check if the
lamp blinks at 4Hz after
operation.
Failed T/M position switch and
harness (failure of TM1 and TM2
harness and their related
switches shown in the figure).
Incorrect wiring.
Repair as required and trace this
chart from the beginning. Shift back to 4H and go to step 5.
5 Start the engine and travel the
vehicle.
Does the speedometer run at
this time? Go to step 6. Failure of speed sensor or
disconnection or short of harness
(for the meter).
After repairing, trace this chart
from the beginning.
6 Check the harness between the
transfer controller and speed
sensor.
(Check the engine rotation
detection harness at the same
time.)
Is any trouble noticed? Failed harness between the
transfer controller and speed
sensor.
After repairing, trace this chart
from the beginning.
(Repair the engine rotation
detection unit, if required.) Go to step 7.
7 Travel the vehicle several
meters, stop it, meet the
permission requirements for
operation limits.
Did you wait for several seconds
after the requirements were
met? Failed controller.
Replace the controller and trace
this chart from the beginning. You did not wait for enough time.
Optimum waiting time is 1
second or maximum 3 minutes
depending on the previous
conditions.
Refer to the paragraph about
operation without failure.
*Before determining a trouble (Non-trouble mode)

TRANSFER CONTROL SYSTEM 7D1-49
From 4L to 4H: After the correction step 4-3(*), 4Lo indicator blinks at 4H.
Step Action Yes No
1 Is the ignition switch ON? Turn it OFF once. Go to step 2.
2 Turn ON the ignition switch and
check the valve. Do not start
the engine.
Has the valve check for 2
seconds been completed
normally? Go to step 3. Refer to the paragraph about the
indicator when it does not react
when shifted from 2H to 4H.
After taking the remedy, trace
this chart from the beginning.
3 Can be shifted to 2H and then to
4L? Go to step 4.
(Impossible usually.)
Failed controller In case of Check 4WD, shifting to
2H is possible.
Returning to 4L is impossible.
Refer to the paragraph about
Check4WD.
4 Set to N position in case of AT
and set to the neutral position in
case of MT and check if the
lamp blinks at 4Hz after
operation.
Failed T/M position switch and
harness (failure of TM1 and TM2
harness and their related
switches shown in the figure).
Incorrect wiring.
Repair as required and trace this
chart from the beginning. Press the operation switch of 4L
and go to step 5.
5 Start the engine and travel the
vehicle.
Does the speedometer run at
this time? Go to step 6. Failure of speed sensor or
disconnection or short of harness
(for the meter).
After repairing, trace this chart
from the beginning.
6 Check the harness between the
transfer controller and speed
sensor.
(Check the engine rotation
detection harness at the same
time.)
Is any trouble noticed? Failed harness between the
transfer controller and speed
sensor.
After repairing, trace this chart
from the beginning.
(Repair the engine rotation
detection unit, if required.) Go to step 7.
7 Travel the vehicle several
meters, stop it, meet the
permission requirements for
operation limits.
Did you wait for several seconds
after the requirements were
met? Failed transfer controller.
Replace the controller and trace
this chart from the beginning. You did not wait for enough time.
Optimum waiting time is 1
second or maximum 3 minutes
depending on the previous
conditions.
Refer to the paragraph about
operation without failure.
*Before determining a trouble (Non-trouble mode)

7D1-50 TRANSFER CONTROL SYSTEM
To neutral: After the correction step 5-2(*), neutral indicator blinks at 4Hz.
Check the function between H and L according to the chart for 4L to 4H instead of check
for the requirements of neutral.
Step Action Yes No
1 Is the ignition switch ON? Turn it OFF once. Go to step 2.
2 Turn ON the ignition switch and
check the valve. Do not start the
engine.
Has the valve check for 2
seconds been completed
normally? Go to step 3. Refer to the paragraph about the
indicator when it does not react
when shifted from 2H to 4H
(7D1-37).
After taking the remedy, trace
this chart from the beginning.
3 Can be shifted to 2H and then to
4L? Go to step 4.
(Impossible usually.)
Failed controller Refer to the paragraph about
shifting from 2H to 4H.
In particular, check if not at the
Check4WD condition, return to
this chart and trace it from the
beginning.
In case of Check4WD, shifting to
2H is possible.
Returning to 4H is impossible.
Refer to the paragraph about
Check4WD.
4 Set to N position in case of AT
and set to the neutral position in
case of MT and check if the lamp
blinks at 4Hz after operation. Failed T/M position switch and
harness (failure of TM1 and TM2
harness and their related
switches shown in the figure).
Incorrect wiring.
Repair as required and trace this
chart from the beginning. Shift back to 4H and go to step 5.
5 Start the engine and travel the
vehicle.
Does the speedometer run at this
time? Go to step 6. Failure of speed sensor or
disconnection or short of harness
(for the meter).
After repairing, trace this chart
from the beginning.
6 Check the harness between the
transfer controller and speed
sensor.
(Check the engine rotation
detection harness at the same
time.)
Is any trouble noticed? Failed harness between the
transfer controller and speed
sensor.
After repairing, trace this chart
from the beginning.
(Repair the engine rotation
detection unit, if required.) Go to step 7.
7 Travel the vehicle several
meters, stop it, meet the
permission requirements for
operation limits.
Did you wait for several seconds
after the requirements were met? Failed controller.
Replace the controller and trace
this chart from the beginning. You did not wait for enough time.
Optimum waiting time is 1
second or maximum 3 minutes
depending on the previous
conditions.
Refer to the paragraph about
operation without failure.
*Before determining a trouble (Non-trouble mode)
For shifting to neutral, 2H and 4L switches should be kept pressed at the same time for 10 seconds.
For shifting from neutral to other position, 2H, 4H or 4L switch should be kept pressed for 10 seconds.
When shifting from neutral to other position, the lamp blinking at 2Hz indicates active condition.
When the lamp keeps blinking at 2Hz, follow the step for the case when the lamp keeps blinking at 2Hz when
shifting between positions.