7A3-2 ON-VEHICLE SERVICE (JR405E)
DESCRIPTION
Before performing on-vehicle service on the automatic
transmission, check that the engine idling speed and
general engine condition are normal.
For shift interlock function, if the ignition key is out of
“LOCK” position, the shift lever select button can not be
pushed. (shift lever can not be operated.)
RTW 77ASH000901
AUTOMATIC TRANSMISSION FLUID (ATF)
Inspect
Remove the transmission dipstick to check the condition
of the ATF.
Check the color and smell of the ATF.
If the ATF is abnormal color or smells burnt, replace it
and investigate the cause of trouble.
Coloor of ATF Condition Clear red Normality
Blackish discoloration Defects of power train
parts (clutches)
W hite turbidity Include water
Discoloration of red brown Deterioration of ATF
ATF LEVEL
Inspect
Hot Level
1. W arm up the engine and the transmission by driving
the vehicle on the road so that the temperature
reaches around 80 °C (176 °F).
Do not turn the engine off.
2. Park the vehicle on a level surface.
3. Apply the parking brake firmly.
4. Let the engine run at idle.
Move the select lever slowly through all the gea
r
positions.
Stop in each gear position just long enough for the transmission to engage.
5. Return the select lever to either “P” or “N”.
6. Remove the ATF level dipstick.
7. W ipe the dipstick clean with a paper towel.
8. Reinsert the dipstick and wait several seconds.
9. Remove the dipstick.
The ATF level should be inside the “H” range on the dipstick.
242R300001
If the ATF level is below the “H” range, ATF must be added.
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ISUZU KB P190 2007
7D-12 TRANSFER CASE
Removal
NOTE: Before removing transmission and transfer
assembly from vehicle, change the transfer mode to
2W D using the 4W D push button switch on dash panel.
1. Disconnect battery ground cable.
2. Raise and support vehicle with suitable stands. Drain
transfer case fluid.
3. Remove rear propeller shaft and front propeller shaft.
NOTE: Apply alignment marks on the flange at both front
and rear sides.
4. Disconnect harness connectors and clip.
Connector: transfer switch, 2W D-4W D actuator,
speed sensor.
NOTE: Avoid turning the vehicle ignition switch to the ON
position when the 2W D-4W D connector is removed
(battery connected).
If the ignition switch must be turned to the ON position,
the controller must first be removed (memory must be
cleared because the CHECK 4W D INDICATOR will
light).
5. Remove transfer case assembly from the vehicle.
Installation
1. Apply a thin coat of molybdenum disulfide grease to
the input shaft spline as shown in the figure.
260R300001
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ISUZU KB P190 2007
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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ISUZU KB P190 2007
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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ISUZU KB P190 2007
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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ISUZU KB P190 2007
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