2004 ISUZU TF SERIES air condition

TRANSFER CONTROL SYSTEM 7D1-41
Diagnosis from symptom
Check4WD lighting up
Step Action Yes No
1 Check what was done before
the trouble occurred.
Was the harness between the
transfer controller and actuator
disconnected with the ignition
kept ON for the purpose of
servicing the vehicle, etc.?
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, 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 (4WD, 4Lo, Check
4WD, 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 Isn’t the harness between the
Check4WD 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 5 times at
least.
To judge the condition more quickly, ask the customer the situation when the Check4WD lamp lighted up.
When the position indicator blinks at a frequency of 4Hz immediately after occurrence of a trouble, 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 standstill so
that possibility of failure around that point is high.)
Status of the transfer when the Check4WD lights up is not always the same. Immediately after occurrence of the
failure, 2H can be operated.

7D1-42 TRANSFER CONTROL SYSTEM
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 (4WD, 4Lo, Check
4WD, neutral) light up for 2
seconds when the ignition
switch is turned ON? Failed operation switch. Only 2H
is stuck at ON condition and 4H-
4L position is internally
disconnected. 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 (4WD, 4Lo, Check
4WD, 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
Check4WD lamp is ON or OFF.
Is the Check4WD 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 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)

7D1-44 TRANSFER CONTROL SYSTEM
After operation, indicator of target position blinks for 1.5 sec. at 2Hz, return to 2H
condition (4WD indicator going out)

Step Action Yes No
1 Keep to press the 4H button
(about 10 seconds).
Does the 4WD indicator blink at
2Hz for 15 seconds and then
blink at 4Hz? Failed actuator motor.
Disconnection of controller motor
drive output circuit, or GND short.
+B fuse blown out.
Disconnection of that harness.
After repairing, trace this chart
from the beginning. Go to step 2.
2 Press the 4H button.
Is the sound of relay heard from
the transfer controller? Go to step 3. Failed controller.
Replace the controller and trace
this chart from the beginning.
3 Is the sound of running motor
heart? Failed control system of the
transfer mechanism. Check and
repair and trace this chart from
the beginning. Failed actuator motor.
Disconnection or GND short of
controller motor drive output
circuit.
After repairing, trace this chart
from the beginning.

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.

7A2-2 TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L)

Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL
RESTRAINT SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN
ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS
COMPONENTS OR THE SRS WIRING. WHEN YOU
ARE PERFORMING SERVICE ON OR NEAR THE
SRS COMPONENTS OR THE SRS WIRING, REFE
R
TO THE SRS SERVICE INFORMATION. FAILURE TO
FOLLOW WARNINGS COULD RESULT IN
POSSIBLE AIR BAG DEPLOYMENT, PERSONAL
INJURY, OR OTHERWISE UNNEEDED SRS SYSTEM
REPAIRS.
CAUTION: Always use the correct fastener in the
proper location. When you replace a fastener, use
ONLY the exact part number for that application.
ISUZU will call out those fasteners that require a
replacement after removal. ISUZU will also call out
the fasteners that require thread lockers or thread
sealant. UNLESS OTHERWISE SPECIFIED, do not
use supplemental coatings (Paints, greases, o
r
other corrosion inhibitors) on threaded fasteners or
fastener joint interfaces. Generally, such coatings
adversely affect the fastener torque and the joint
clamping force, and may damage the fastener.
When you install fasteners, use the correct
tightening sequence and specifications. Following
these instructions can help you avoid damage to
parts and systems.
General Description
The AW30-40LE is a 4–speed fully automatic
transmission. It uses a microcomputer as a control unit
to judge running conditions including throttle opening
rate and vehicle speed, then it sets the shifting point in
the optimum timing so that best driving performance
can be achieved.
In addition, the built–in shift mode select function can
select three shift modes according to the driver's
preference:
 Normal mode –Normal shift pattern.
 3rd Start mode –Starts in 3rd gear to reduce
slippage on ice or snow.
 Power mode has a delayed up shift when more
powerful acceleration is required.
Also, the built–in fail–safe function (“backup mode")
assures driving performance even if the vehicle speed
sensor, throttle signal or any solenoid fails.
Further, the self–diagnostic function conducts diagnosis
in a short time when the control system fails, thus
improving serviceability.
The major features of AW30-40LE are as follows:

A compact structure consisting of 2 sets of planetary
gears and flat torque converter.
 Electronic control selects the optimum shift mode according to the driving conditions.
 Electronic control maintains the optimum hydraulic
pressure for clutch, band brake as well as
transmission so that shift feeling is improved.
 Two sets of planetary gears reduce friction of powe
r
train.
Also, a lockup mechanism in the torque converter
reduces fuel consumption.
 Wide gear ratio and high torque rate of torque
converter provide excellent starting performance.

TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L) 7A2-21

Diagnostic Trouble Codes
The purpose of the “Diagnostic Trouble Codes" mode is
to display stored TCM trouble codes.
When “Diagnostic Trouble Codes" is selected an
“ Application Menu" screen appears.
Clear DTC Information
The purpose of the “Clear DTC Information" mode is to
command the clearing of stored TCM trouble codes.
When “Clear DTC Information" is selected, a “Clea
r
DTC Information", warning screen appears. This screen
informs you that by cleaning DTC's, “all stored DTC
information in controller will be erased".
Do you want to clear DTC's (Yes/No).
Press either the Yes or No key when answering.
After clearing codes, confirm system operation by test
driving the vehicle.
Allow the vehicle to shift through all four forward gears
in a manner which attempts to repeat the failure
condition.
NOTE: When the trouble has not been repaired and
the trouble code cannot be erased, check the vehicle
again.
DTC Information
When “DTC Information" is selected, an “Application
Menu" appears with a list of DTC information function
keys addressing DTC specifics and their origins.
Function key selections may vary for particular vehicle
and/or system.
Data Display
The purpose of the “Data Display" mode is to
continuously monitor data parameters.
The current actual values of all important sensors and
signals in the system are display through F1 mode.
When “Data Display" is selected an “Application Menu"
appears. Please select either “Engine" or “Transmission
Data Display".
See “Transmission Data" on next page.
Snapshot
When “Snapshot" is selected an “Application Menu"
appears.
When “Transmission Snapshot" application is selected
from the “Application Menu", a “Snapshot Menu"
appears, displaying several options. “Snapshot" options
may vary from one system to another.
“ Snapshot" allows a recording of all vehicle parameters.
There parameters may then be replayed at a future
point in time.
This action allows you to focus on making the condition
occur, rather than trying to view all of the data in
anticipation of the fault. The snapshot will collect
parameter information around a trigger point that you
select.

When a snapshot is taken. It is recorded onto the
PCMCIA memory card. When the Tech 2 is powered
down. Snapshots are not lost.
Actuator Tests
The purpose of “Actuator Tests" mode is to check fo
r
correct operation of electronic system actuators.
Lamps
You can operate the lamps by pressing the “ON" and
“ OFF" buttons.
Preconditions: none
Solenoid
Solenoid A(S1), Solenoid B(S2)
You can operate the solenoids by pressing the “ON"
and “OFF" buttons.
Preconditions: P –N position, no vehicle speed, no
engine speed
Pressure Control Solenoid (PCS)
You can set desired PCS Current using the “ON" (+20)
and “OFF" (-20) button. The PC Solenoid Data informs
about PCS Current, Pressure and Duty Cycle.
Preconditions: P –N position, no engine speed, no
vehicle speed
NOTE: Freeze Frame
Freeze Frame is an element of the Diagnostic
Management System which stores various vehicle
information at the moment an emission-related fault
is stored in memory and when the Check Transe
Lamp is commanded on. These data can help to
identity the cause of a fault. Refer to Storing An
d
Erasing Freeze Frame Data for more detaile
d
information.