ignition ISUZU KB P190 2007 Workshop Repair Manual

TRANSFER CONTROL SYSTEM 7D1-41
CONNECTOR LIST
No. Connector face No. Connector face
B13



White
Fan switch B85



W eld splice 7 (Ground)
B23


White
Meter-A B95



White

Keyless entry control unit
B24


White
Meter-B B96



Gray PIM1
B54


White
J/B I2 B97



WhitePIM2
B56


White
J/B I4 C2



SilverEngine room-RH ground
B62


White
Ignition switch (IGSUB: G1) C4



Sky blueFront wiper motor
B63


White
Ignition switch (IGSUB: G2) C5

~
C14 NOT USED
B64




W eld splice 1 (Illumination) C36



SilverEngine room-LH; ground
B65



W eld splice 2 (Ground) C56
(C24SE)

ECM
B66


White
4 ×4 switch C56
(4JH1-TC)


Black
ECM-A


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ISUZU KB P190 2007

TRANSFER CONTROL SYSTEM 7D1-47
3. Shifting from 4H to 4L
3-1 When the 4L indicator flashes at 2Hz
W hen 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 deviate 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.
W hen 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-T)
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. Due to 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.
W aiting 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 for
3 minutes. After that, the waiting time increases up to 3 minutes in 2 minute intervals.
W hen it is clear that the above condition has continued and reduction of waiting time is required, 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 recommended
(MT) should be at the neutral.

These requirements for permission should all be 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.

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ISUZU KB P190 2007

TRANSFER CONTROL SYSTEM 7D1-51
Trouble diagnosis based on the operation switch, transfer indicator lamp and operating
sound “Check 4WD” indicator ON (operation guard based on the transfer actuator
position detection error)
This condition indicates a faulty circuit related with the detection (limit) switches of the system actuator.
Detection (limit) switches detect the actuator operating angle based on their combinations.
The controller monitors transition of the actuator based on the combination of the detection (limit) switch output.
If the transition based on the combinations indicates some trouble, it is memorized, and shifting operation is
stopped when the trouble is counted 5 times, and the “Check 4W D” indicator lights up. At this time, the system
permits operation to 2H only.
W hen such a condition occurs, inspection of the transfer shift actuator, checking of the harness related with the
detection (limit) switch, and erasure of the memory of the controller is required.
(Refer to the memory erasure procedure for the erasure of the memory.)
At this time, the position indicator may flash at 4Hz. It means that a detection (limit) switch trouble wad detected
in the operation process shown by that position indicator (example: 4W D indicator when shifting from 2H to 4H).

Caution:
During trouble diagnosis and correction, do not turn ON the ignition with the harness connector of the
transfer actuator disconnected. (Do not disconnect the harness connector of the transfer actuator when
the ignition is ON.)
If the controller is connected during this condition, a limit SW trouble is judged and the above-described
“Check 4WD” condition occurs.
This can be reset by clearing the memory.
When disconnecting the harness connector of the actuator and turning the ignition ON is required, remove
the controller at the same time or remove the IG power fuse of the transfer controller.



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7D1-52 TRANSFER CONTROL SYSTEM
Memory erasing procedure
1-1 Memory erasing with operation button

1. Turn on the ignition.
2. Shift to the “N” position with the vehicle stopped.


RTW 77DSH000101
3. Simultaneously push the 3 buttons (2H/4H/4L) for 20
seconds.
4. Confirm the “Check 4W D” indicator on the meter panel is OFF.
5. Before erasing the memory, check that the circuit of the T/F actuator position detection harness is normal.


1-2 Memory erasing with short harness (Other procedure)
1. Prepare two pieces of short harness with the end sharpened like a needle (about 20 cm(7.9 in) long).
2. Turn OFF the ignition.
3. Keeping the connector of the transfer controller connected,
set the short harness from the back of the connector as
illustrated.
4. Turn ON the ignition, wait for 2 seconds, and then turn OFF the ignition after confirming the relay sound.
5. Disconnect the short harness, turn ON the ignition again, and confirm the “Check 4W D” lamp on the meter panel is
OFF.
6. Before erasing the memory, check that the circuit of the T/F actuator position detection harness is normal.






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7D1-54 TRANSFER CONTROL SYSTEM
Diagnosis from symptom
Check4WD lighting up
Step Action Yes No
1 Check what was done before the
trouble occurred.
W as the harness between the
transfer controller and actuator
disconnected with the ignition
kept ON for the purpose of
servicing the vehicle?
Or, was the ignition turned ON
(power supplied to the transfer
controller) with the harness of
the actuator removed? If the power is supplied with the
actuator not connected, a faulty
position detection switch is
considered.
Clear the memory and trace this
chart from the beginning. Go to step 2.
2
Is the ignition switch ON? Go to step 3.
Turn the ignition switch ON and
trace this chart from the
beginning.
3 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Go to step 4.
Indicator lamp burnt out.
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
4 Has the harness between the
Check4W D indicator and
transfer controller GND shorted? GND (body) short of the indicator
harness.
After repairing, trace this chart
from the beginning. Go to step 5.
5
Check the continuity of harness
between the transfer controller
and transfer actuator. Check
the power short and GND short.
Check the GND harness of the
transfer actuator.
Is a trouble noticed? Repair the harness, clear the
memory and trace this chart from
the beginning. Go to step 6.
6
Check the limit switch of the
actuator.
Is a trouble noticed? Failed actuator. Replace the
actuator, clear the memory and
trace this chart from the
beginning. Clear the memory and trace this
chart from the beginning.
Failed controller.
Replace the controller, clear the
memory and trace this chart from
the beginning.
To check the operation after completing the repair and clearing the memory, shift between 2H and 4L at least 5
times.
To judge the condition more quickly, ask the customer what happens when the Check4W D lamp lights up.
W hen the position indicator blinks at a frequency of 4Hz immediately after trouble occurs, the position of failure
which the indicator shows may be limited.
(Since it indicates the situation immediately before detection of failure, whether the vehicle is running or at a
standstill, the possibility of failure around that point is high.)
Status of the transfer when the Check4W D lights up is not always the same. Immediately after failure occurs, 2H
can be operated.



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TRANSFER CONTROL SYSTEM 7D1-55
Cannot shift from 2WD to 4H or 4L.
When shifting from 2H to other position, the indicator (4WD, 4Lo, Check4WD, neutral)
does not respond.
Step Action Yes No
1 Is the ignition switch ON? Go to step 2.
Turn the ignition switch ON and
trace this chart from the
beginning.
2 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Failed operation switch. Or,
Failed controller. Indicator lamp burnt out.
Disconnected harness wire.
After repairing, trace this chart
from the beginning.


Even after correction step 1-1(*), 4WD indicator blinks at 4Hz and changes to 2H after 10
seconds.
Step Action Yes No
1 Is the ignition switch ON? Go to step 2.
Turn the ignition switch ON and
trace this chart from the
beginning.
2 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Go to step 3.
Indicator lamp burnt out.
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
3 After 2 seconds, check that the
Check4W D lamp is ON or OFF.
Is the Check4W D lamp OFF? Go to step 4.
Failed actuator position detection
switch (LS1, LS2, LS3, LS4,
GND).
Short or disconnection of harness
of this detection switch.
After repairing, trace this chart
from the beginning.
4 Press the 4H button.
Is sound of relay heard from the
transfer control? Go to step 5.
Failed controller.
Replace the controller and trace
this chart from the beginning.
5 Is the sound of a running motor
heard? Failed control system of the
transfer mechanism. Check and
repair and trace this chart from
the beginning. Failed actuator motor.
Disconnected controller motor
drive output circuit, GND short
circuit. +B fuse blown out.
Disconnection of that harness.
After repairing, trace this chart
from the beginning.
*Before determining a trouble (Non-trouble mode)




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ISUZU KB P190 2007

7D1-58 TRANSFER CONTROL SYSTEM
Transfer cannot shift to another position (Except “Check 4WD” failure).
When shifting to another position, indicator (4WD, 4Lo, Check4WD, neutral) does not
respond (Current condition keeping).
Step Action Yes No
1 Is the ignition switch ON? Go to step 2.
Failed indicator and harness
(W hen lighting).
After repairing, trace this chart
from the beginning.
2 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Go to step 3.
All indicators are burnt out
(Check for GND short circuit
between the indicator and
transfer controller).
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
3 Press the other positions button.
Is the sound of relay heard from
under the seat, and the sound of
a running motor heard? Failed controller.
After replacing the controller,
trace this chart from the
beginning. *Failed operation switch. Or
harness for the operation switch
has disconnected or shorted.
* The operation switch is an analog type switch which reads the internal composite resistance value at the time of operation. If an abnormal value is detected, it is kept at the home position (The position before operating it).



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7D1-60 TRANSFER CONTROL SYSTEM
Though the indicator responds when shifting from 4H to 2H(or other position), it returns
to 4H.
Step Action Yes No
1 Is the ignition switch ON? Go to step 2.
Turn the ignition switch ON and
trace this chart from the
beginning.
2 Does the transfer-related
indicators (4W D, 4Lo, Check
4W D, neutral) light up for 2
seconds when the ignition switch
is turned ON? Go to step 3.
Indicator lamp burnt out.
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
3 After 2 seconds, check if the
Check4W D lamp lights up.
Is the Check4W D lamp OFF? Go to step 4.
Failed actuator position detection
(limit) switch (LS1, LS2, LS3,
LS4, GND).
Short or disconnection of harness
of this detection switch.
Refer to paragraph of
Check4W D.
After repairing, trace this chart
from the beginning.
4 Press the 2H button.
Is the sound of relay heard from
the transfer controller? Go to step 5.
Failed controller.
Replace the controller and trace
this chart from the beginning.
5 Is the sound of a running motor
heart? Failed control system of the
transfer mechanism. Check and
repair and trace this chart from
the beginning. Failed actuator motor.
Disconnection of controller motor
drive output circuit or GND short.
After repairing, trace this chart
from the beginning.
If the motor does not or cannot run at all (stuck transfer mechanism, disconnected motor, failed drive circuit), the
lamp blinks at 4Hz when the position is shifted to other position by pressing the button for more 10 seconds (20
seconds in case of neutral position).



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TRANSFER CONTROL SYSTEM 7D1-61
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
Check4W D 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 use 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 detected? 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
Run the vehicle for 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)


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7D1-62 TRANSFER CONTROL SYSTEM
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 4W D, shifting to
2H is possible.
Returning to 4L is impossible.
Refer to the paragraph about
Check4W D.
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 use 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 detected? 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
Run the vehicle for 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)



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