2004 ISUZU TF SERIES ESP

7A2-32 TRANSMISSION CONTROL SYSTEM (AW30 –40LE) (V6 3.5L)

Clear DTC
NOTE: If you clear the DTC (Diagnostic Trouble
Codes) you will not be able to read any codes recorded
during the last occurrence.
NOTE: To use the DTC again to identify a problem,
you will need to reproduce the fault or the problem.
This may require a new test drive or just turning the
ignition on (this depends on the nature of the fault).
1. IF you have a Tech 2:
1. Connect the Tech 2 if it is still not connected go
through Tech 2 OBD CONNECTION.
2. Push “F1: Clear DTC Information" in the
Application Menu and answer “Yes" to the
question “Do you want to clear DTC's?"
a. When a malfunction still exists and the Tech 2 displays “AW30-40 CODES NOT
CLEARED". This means that the problem is
still there or that the recovery was not done.
Please go to DTC CHECK.
b. When a malfunction has been repaired and the recovery is done the Tech 2 displays
“ AW30-40LE CODES CLEARED".
2. When you have no Tech 2, the storaged trouble
codes can be cleared by shorting the terminals
No.11 and No.4 or 5 (ground) of data link connecto
r
with a lead wire for 1  6 seconds.
DTC Check
1. Diagnostic Trouble Codes (DTC) have been
identified by Tech 2.
2. You have written the list of the DTCs. The order o
f
the malfunctions has no meanings for this TCM.
Usually only one or two malfunctions should be set
for a given problem.
3. Check directly the DTCs you identified. The DTCs
are sorted by number. Refer to Diagnostic Trouble
Code (DTC) Identification in this section.
TCM Precaution
The TCM can be damaged by:
1. The electrostatic discharge
2. The short circuit of some terminals to voltage or to
ground.
Electrostatic Discharge Damage Description: 1. Electronic components used to control systems are often designed to carry very low voltage, and
are very susceptible to damage caused by
electrostatic discharge. It is possible for less than
100 volts of static electricity to cause damage to
some electronic components. By comparison, it
takes as much as 4,000 volts for a person to even
feel the zap of a static discharge.
2. There are several ways for a person to become
statically charged. The most common methods o
f
charging are by friction and induction. An example
of charging by friction is a person sliding across a
car seat, in which a charge of as much as 25,000
volts can build up. Charging by induction occurs
when a person with well insulated shoes stands
near a highly charged object and momentarily
touches ground. Charges for the same polarity are
drained off, leaving the person highly charged with
the opposite polarity. Static charges of either type
can cause damage, therefore, it is important to
use care when handling and testing electronic
components.
NOTE: To prevent possible electrostatic discharge
damage:
1. Do not touch the TCM connector pins or soldered
components on the TCM circuit board.
2. Be sure to follow the guidelines listed below i
f
servicing any of these electronic components:
3. Do not open the replacement part package until it is time to install the part.
4. Avoid touching electrical terminals of the part.
5. Before removing the part from its package, ground
the package to a known good ground on the
vehicle.
6.
Always touch a known good ground before handling
the part. This step should be repeated before
installing the part if the part has been handled
while sliding across the seat, while sitting down
from a standing position or while walking some
distance.
Information On TCM
1. The Transmission Control Module (TCM) is located
in the place of a clutch pedal and is the control
center of the electronic transmission control
system.
2. The TCM must be maintained at a temperature below 85

C (185

F) at all times. This is most
essential if the vehicle is put through a paint baking
process. The TCM will become inoperative if its
temperature exceeds 85

C (185

F). Therefore, it is
recommended that the TCM be removed or that
temporary insulation be placed around the TCM
during the time the vehicle is in a paint oven o
r
other high temperature process.
3. The TCM is designed to process the various inputs and then respond by sending the appropriate
electrical signals to control transmission upshift,
downshift, shift feel and torque converter clutch
engagement.
4. The TCM constantly interprets information from the
various sensors, and controls the systems that
affect transmission and vehicle performance. By
analyzing operational problems, the TCM is able to

ON-VEHICLE SERVICE (AW30 –40LE) 7A3-5

Speed Change and Lock-Up Pattern
If you select a speed as shown below by specifying
respective positions of transmission shift lever, transfe
r
switch and pattern select switch, the transmission
control computer controls speed change and lock-up
operations based on the specified pattern in accordance
with the degree of throttle opening and vehicle speed.
Pattern select sw. position Transmission shift position


D 3 2 L
NORMAL, POWER 1st 
[2nd] 
[3rd] 
[O/D] 1st 
[2nd] 
[3rd] 1st 
2nd
(3rd) 1st
(2nd)
3rd START 3rd fixing — —

[ ]: The lock-up operation is available.
( ): Transmission is shifted at high speed to prevent overrun.


Overdrive and Lock-Up Operating Conditions
The overdrive and lock-up clutch operate if the following
conditions are satisfied.
Overdrive Lock-up clutch
Shift pattern position
NORMAL NORMAL
Transmission shift position
D range 
Brake lamp switch
— OFF
Throttle opening
Fully closed Except fully closed
Accelerator About 52 km/h (32 mph) or more 2nd: About 76 km/h (47 mph) or
more
Vehicle speed Deceleration About 42 km/h (26 mph) or more 3rd: About 56 km/h (35 mph) or more
O/D: About 67 km/h (42 mph) or
more

7A3-12 ON-VEHICLE SERVICE (AW30 –40LE)

Manual Shifting Test
NOTE: With this test, it can be determined whether the
trouble lies within the electrical circuit or is a mechanical
problem in the transmission.
1. Disconnect TCM connector
Inspect manual driving operation
2. Inspect manual driving operation
Check that the shift and gear positions correspond
with the table.
If the “L", “2", “3" and “D" range gear positions are
difficult to distinguish, do perform the following road
test.
While driving, shift through the “L", “2", “3" and “D"
ranges. Check that the gear change corresponds to
the gear position.
If any abnormality is found in the above test, do
perform the stall, time lag or gear change tests.



RUW37ASH004101
3. Connect TCM connector
With the engine off, connect the TCM connector.


Stall Test



RUW37ALH000101
The object of this test is to check the overall
performance of the transmission and engine b
y
measuring the maximum engine speeds at the “D" and
“ R" ranges.
NOTE:
1. Perform the test at normal operation fluid
temperature (50 – 80 
C or 122 – 176 
F).
2. Do not continuously run this test longer than 5 seconds.

UNIT REPAIR (AW30–40LE) 7A4–37
Diaassembly, Inspection and
Reassembly of minor Components
NOTE: The instructions here are organized so that you
work on only one component group at a time.
This will help avoid confusion from similar-looking parts
of different subassemblies being on your workbench at
the same time.
The component groups are inspected and repaired from
the converter housing side.
As much as possible, complete the inspection, repair
and reassembly before proceeding to the nex t
component group. If a component group cannot be
reassembled because parts are being ordered, be sure
to keep all parts of that group in separate container
while proceeding with disassembly, inspection, repair
and reassembly of other component groups.
Recommended ATF type DEXRON III.
General Cleaning Notes:
1. All disassembled parts should be washed clean and
any fluid passages and holes should be blown
through with compressed air.
2. When using compressed air to dry parts, always aim
away from yourself to prevent accidentally spraying
automatic transmission fluid in your face.
3. The recommended automatic transmission fluid
should be used for cleaning.
Parts Arrangement:
1. After cleaning, the parts should be arranged in
proper order to allow performing inspection, repairs,
and reassembly with efficiency.
2. When disassembling a valve body, be sure to keep
each valve together with the corresponding spring.
3. New brakes and clutches that are to be used for
replacement must be soaked in transmission fluid
for at least thirty minutes before assembly.
General Assembly:
1. All oil seal rings, clutch discs, clutch plates, rotating
parts, and sliding surfaces should be coated with
transmission fluid prior to reassembly.
2. All gaskets and rubber O-ring should be replaced.
3. Make sure that the ends of a snap ring are not
aligned with one of the cutouts and are installed in
the groove correctly.
4. If a worn bushing is to be replaced, the
subassembly containing that bushing must be
replaced.
5. Check thrust bearings and races for wear or
damage. Replace if necessary.
6. Use petroleum jelly or vaseline to keep parts in
place.

7A1-14 CONSTRUCTION AND FUNCTION
CONTROL VALVE

Employing the direct electronic control (Direct Electronic Shift Control: DESC) for the clutch pressure has
simplified the oil pressure circuit, reduced the number of functional components and made the control
valve compact.

The control valve body is divided into the upper body and lower body. All solenoids, oil pressure switch
and ATF thermo sensor are installed to the lower body.

Three-way valve type solenoids providing high responsibility are employed. Some of the solenoids are
switched between ON and OFF and others repeat ON and OFF at 50Hz (duty cycle system).
Functionally, some supply output pressure when power is not supplied and others drain the output
pressure.

When the solenoid is driven based on the signal from the TCM, the oil pressure is changed. The valve is
operated by the difference of the oil pressure.


Figure 22. Construction of Valve Body

CONSTRUCTION AND FUNCTION 7A1-15

Line Pressure Solenoid

The line pressure solenoid is turned ON or OFF according to the signal from the TCM. It switches the
line pressure between high and low pressure.

While no power is supplied, the solenoid supplies high pressure.

Shift Solenoid

The shift solenoid is of the duty cycle type which are turned ON or OFF at 50Hz. The ratio of the ON and
OFF time can be freely controlled in the range of 0 - 100%.

While no power is supplied, the solenoid supplies output pressure.

The low clutch solenoid adjusts the low clutch pressure, the high clutch solenoid the high clutch pressure,
the 2-4 brake solenoid the 2-4 brake pressure and the low & reverse brake solenoid the low & reverse
brake pressure respectively.

Lock-up Solenoid

The lock-up solenoid is of the duty cycle type which is turned ON or OFF at 50Hz. The ratio of ON and
OFF time can be freely controlled in the range of 0-100%.

While no power is supplied, the solenoid drains the output pressure.




Figure 23. Shift Solenoid Figure 24. Lock-up Solenoid

Figure 25. Location of Solenoid

7A1-16 CONSTRUCTION AND FUNCTION
Control Valve Fail-safe Function

To prevent interlocking due to engagement of more than three clutches and brakes at the same time, the
2-4 brake fail-safe valve A and B, and the low & reverse brake fail-safe valve A and B are provided.

When oil pressure is generated in the high clutch and the low clutch, the 2-4 brake solenoid is turned ON
to drain the oil pressure applied to the 2-4 brake.

When oil pressure is generated in the high clutch or 2-4 brake, the low & reverse brake solenoid is turned
ON to drain the oil pressure applied to the low & reverse brake.



Oil Pressure Switch

The oil pressure switch detects the oil pressure supply condition to the clutch and brake and sends the
detection result to the TCM.

The oil pressure switch is turned ON when the oil pressure reaches the switch working pressure and
turned OFF when the pressure decreases below the specified value.

The high clutch oil pressure switch detects the high clutch oil pressure, 2-4 brake oil pressure switch the
2-4 brake oil pressure, and the low & reverse brake oil pressure switch the low & reverse brake oil
pressure respectively.




Figure 27. Oil Pressure Switch Figure 28. Location of Oil Pressure Switch

7A1-24 CONSTRUCTION AND FUNCTION
BRAKE SWITCH

The brake switch is installed to the brake pedal. When the driver steps on the brake pedal, an electric
signal is sent to the TCM.



Brake Switch
Accelerator Pedal
Brake Pedal



TCM A3 +12V
Figure 45. Brake Switch Figure 46. Pin Assignment


MODE SELECT SWITCH

The mode select switch is installed beside the select lever. When the driver selects the PWR or 3rd, an
electric signal is sent to the respectively. It turns ON the indicator lamp in the meter.

The 3rd START mode can be used only in the D range.

Mode Select Switch
Gear Select Lever









Power 3rd Illumination
Lamp
1 (Illumination)
2 (Ground)
3 (TCM A24)
4 (No Connection)
5 (TCM A11)
6 (Ground)

21
65 4 3
Figure 47. Mode Select Switch Figure 48. Pin Assignment