ignition ISUZU TF SERIES 2004 Workshop Manual

TRANSFER CONTROL SYSTEM 7D1-45
Transfer cannot shift to a position other than 4H.
When shifting from 4H to other position, indicator (4WD, 4Lo, Check4WD, neutral) does
not respond (Only 4WD keeps lighting).
Step Action Yes No
1 Is the ignition switch ON? Go to step 2. Failed 4WD indicator and
harness.
After repairing, 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?
Then, only 4H lights up. Go to step 3. Indicator lamps other than the
4WD indicator are burnt out.
(Check for GND short circuit
between the 4WD indicator and
transfer controller.)
Disconnected harness wire.
After repairing, trace this chart
from the beginning.
3 Press the 2H button.
Is the sound of relay heard from
under the seat, and the sound of
running motor heard? Failed controller.
After replacing the controller,
trace this chart from the
beginning. *Failed operation switch. Or
disconnected or shorted of the
harness for the operation switch.
* 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 judged to be an instruction to 4H.

TRANSFER CONTROL SYSTEM 7D1-47
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 (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 if the
Check4WD lamp lights up.
Is the Check4WD 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
Check4WD.
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 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).

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.

TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L) 7A2-11

Comparison of mode
1. The normal drive mode is set at the normal shift
points.
2. The shift points of the power drive mode are shifted
to the higher speed side, compared to the normal
drive mode.
3. The 3rd start mode is a special mode used
exclusively for starting in third gear.
3rd start Mode
1. The 3rd start switch will operate when switched on
after all of the following conditions are present:
a. The gear select position is “D" range only.
b. Vehicle speed is 11 km/h (7 mph) or less.
c. Transmission oil temperature is 120

C (248

F)
or less.
d. Accelerator opening is at 8% or less.
2. Cancel Release
1. Cancellation by driver
a. Turning off the 3rd start mode switch
b. Shifting select position to “3", “2", or “L" (3rd
start mode is not canceled by selecting “N",
“ R", or “P")
c. Ignition key is turned off.
2. Automatic cancellation
a. When vehicle runs at 34 km/h (21mph) o
r
more for 1 second or more
b. When transmission oil temperature reaches 120

C (284

F) or above
NOTE: The mode returns to normal drive mode o
r
power drive mode after the 3rd start mode is canceled.
Backup Mode
If a major system failure occurs which could affect
safety or damage the transmission under normal
vehicle operation, the diagnostic system detects the
fault and overrides the Transmission Control Module
(TCM).
The “CHECK TRANS" light flashes to alert the driver,
and the transmission must be manually shifted as
follows:


Select lever position Gear Ratio Selected
D 4 (Fourth)
Manual 3 4 (Fourth)
Manual 2 3 (Third)
Manual L 3 (Third)
R Reverse
Shifts are firmer to prevent clutch slip and consequent
wear. The fault should be corrected as soon as
possible.

TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L) 7A2-13

CAN bus systems in automatic
transmission control (AW30-40LE)
The automatic transmission control system in AW30-
40LE uses high speed CAN bus system .The individual
CAN bus systems are connected via two interfaces and
can exchange information and data. This allows control
modules that are connected to different CAN bus
systems to communicate.
High speed CAN bus
Transmission control modules in the vehicle that require
continuous, rapid communication are connected to the
high speed CAN bus. For example, the automatic
transmission is continuously notified of the current
engine load status. Since the automatic transmission
control module has to react immediately to load status
changes, rapid communication is required between the
engine control module and the automatic transmission
control module. The high speed CAN bus in the AW30-
40LE is designed as a two-wire CAN bus (twisted pair).
The wires are shielded and twisted. The transfer rate is
500 K baud.




RUW37ASF000401
Diagnosis
Electronic Diagnosis
How To Diagnose The Problem
1. To avoid incorrect diagnostics, this book needs to
be followed accurately. Unless stated, do not jump
directly to a section that could contain the
solution. Some important information may be
missed.
2. The sections in CAPITALS and bold are the main
sections that can be found in the contents.
3. The go to “
SECTION"
means to continue to check
going to the “section".
4. The go through “
SECTION"
means to go through
the “section" and then to go back to the place the
go through was written.
5. BASIC ELECTRIC CIRCUITS:
You should understand the basic theory o
f
electricity. This includes the meaning of voltage,
amps, ohms, and what happens in a circuit with an
open or shorted wire. You should also be able to
read and understand wiring diagrams.
Check Trans Indicator
Find CHECK TRANS indicator and verify if it is
A. Flashing: Go to DIAGNOSTIC CHECK.
B. Staying on: Go through CHECK TRANS CHECK
.
C. Is never ON when the ignition key is turned on: Go through CHECK TRANS CHECK
D. Is ON during 3 seconds at ignition but OFF after: Normal operation. No DTC or malfunction.



RTW37ASH000401
On Board Diagnostic Check
This test determines if the transmission or its input or
output connections or sensors are failing.
1. Connect the Tech 2: Go through Tech 2 OBD
CONNECTION .
2. Turn on the ignition but not the engine.
3. Push “F0" on Tech 2 to see the Diagnostic Trouble
Code (DTC):

7A2-14 TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L)

4. Do you have a DTC?
YES: write down all code numbers and do the DTC
CHECK
NO: the DTC can not help you find the problem.
1. Go through “
CHECK TRANS" CHECK
2. If it is flashing and the flash is 0.4 seconds ON
and 0.4 seconds OFF, this means that you
should have a DTC stored. Please recheck go
to DIAGNOSTIC CHECK
and if you find the
same problem, replace the Powertrain Control
Module (TCM).
Normal




C07RY005-1
Abnormal





C07RY00042-1

“Check Trans" Check

1. Indicator is ON during 3 seconds at ignition but it is
OFF after the engine starts. The indicator is
working normally go to DIAGNOSTIC CHECK
.



RTW37ASH000401
Normal





C07RY005-1

TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L) 7A2-15

2. Indicator is flashing and the flash is 0.4 seconds
ON and 0.4 seconds OFF always when ignition is
on (engine cranked or not). This means that there is
a malfunction. Go to DIAGNOSTIC CHECK
.
Abnormal





C07RY00042-1
3. Indicator is staying ON always when Ignition is ON.
1. This means that connection between the lamp
and the indicator control unit is shorted to
ground.
2. Verify if instrument panel terminal 2 o
f
connector B –23 is shorted to ground.
3. Verify if the indicator control unit connector C –
95 terminal 3 is shorted to ground.
4.
Verify that the instrument panel terminal 30 of
connector B –24 is connected to battery.
5. If problem solved: Go to CHECK TRANS
INDICATOR .
NO: Replace Transmission Control Module
(TCM).
4. Indicator is staying OFF with the ignition ON
(engine OFF).
1. This means that connection between the lamp
and the indicator control unit is shorted to
battery or opened.
2.
Verify if instrument panel terminal 2 of
connector B –23 is shorted to battery or open.
3. Verify if the indicator control unit connector C –
95 terminal 3 is shorted to battery or open.
4.
Verify that the instrument panel terminal 2of
connector B –23 is connected to battery. If not,
check the fuses and the connections (terminal
11 of connector H –6) voltage.

7A2-18 TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L)

2. Connecting the Tech 2



901RW180

Legend
(3) SAE 16/19 Adapter
(1) PCMCIA Card (4) DLC Cable
(2) RS 232 Loop Back Connector (5) Tech 2



Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. The Isuzu System PCMCIA card (1) inserts into
the Tech 2 (5).
2. Connect the SAE 16/19 adapter (3) to the DLC
cable (4).
3. Connect the DLC cable to the Tech 2 (5)
4. Mark sure the vehicle ignition is off.