Page 1697 of 2100

7A1±10
TRANSMISSION CONTROL SYSTEM (4L30±E)
Functions of Input / Output Components
ComponentsFunction
Speed sensor
(fixed to transmission)Senses rotation of output shaft and feeds the data to Powertrain Control Module
(PCM).
Throttle position sensor
(TPS)
(fixed to engine)Senses the extent of throttle valve opening and the speed of the throttle valve
lever motion to open the valve. Feeds the data to PCM.
I
N
Brake switch
(fixed to brake pedal)Senses whether the driver has pressed the brake pedal or not and feeds the
information to PCM.
N
P
UMode switch (fixed to
transmission)Senses the select lever position, and feeds the information to PCM.
U
T
S
Power drive switch
(fixed to front console)Senses whether the driver has selected the power mode, and feeds the
information to PCM.
S
IT/M oil temperature sensorSenses the T/M oil temperature and feeds the data to PCMI
G
N
A
Engine coolant
temperature sensorSenses the engine coolant temperature, and feeds the data to PCM.
A
LEngine speed signalFeeds the signals monitoring engine speed to PCM from crank angle sensor.L
Air conditioning informationSenses whether the air conditioner has been switched on or not, and feeds the
information to PCM.
Winter switch (fixed to front
console)Senses whether the driver has selected the winter mode, and feeds the
information to PCM.
Cruise controller
(Overdrive OFF signal)Downshift takes place when overdrive OFF signal is received from auto cruise
controller integrated in PCM.
O
U
T
S
Shift solenoid A, BSelects shift point and gear position suited to the vehicle running condition on
the basis of PCM output.
P
U
TS
O
L
E
Band apply solenoidControls oil flow suited to the vehicle running condition on the basis of PCM
output.
S
I
G
E
N
O
I
Torque Converter
Clutch PWM solenoidControls clutch apply suited to the vehicle running condition on the basis of PCM
output.
G
N
A
LI
DForce motor
(Pressure regulator
valve)Adjusts the oil pump delivery pressure to line pressure suited to the vehicle
running condition on the basis of PCM output.
Page 1698 of 2100

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±11
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 ªSECTIONº means to continue to check
going to the ªsectionº.
4. The GO THROUGH ªSECTIONº means to go
through the ªsectionº and then to go back to the place
the GO THROUGH was written.
5. BASIC ELECTRIC CIRCUITS:
You should understand the basic theory of 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 2 seconds at ignition but OFF after:
Normal operation. No DTC or malfunction.
821R200014
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 II
CONNECTION.2. Turn on the ignition but not the engine.
3. Push ªF0º on Tech 2 to see the Diagnostic Trouble
Code (DTC):
4. Do you have a DTC?
YES: write down all code numbers and do the DTC
CHECK
NO: the DTC can not help you finding the problem.
1. GO THROUGH ªCHECK TRANSº CHECK
2. If it is flashing and the flash is 0.2 seconds ON and
0.2 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
(PCM).
Normal
C07R200005
Abnormal
C07R200006
Page 1699 of 2100

7A1±12
TRANSMISSION CONTROL SYSTEM (4L30±E)
ªCheck Transº Check
1. Indicator is ON during 2~3 seconds at ignition (or
when the engine is cranked) but it is OFF after the
engine starts. The indicator is working normally GO
TO DIAGNOSTIC CHECK.
821R200014
Normal
C07R200005
2. Indicator is flashing and the flash is 0.2 seconds ON
and 0.2 seconds OFF always when ignition is on
(engine cranked or not). This means that there is a
malfunction. GO TO DIAGNOSTIC CHECK.Abnormal
C07R200006
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 27 of connector
I±24 is shorted to ground.
3. Verify if the indicator control unit connector B±16
terminal 20 is shorted to ground.
4. Verify that the instrument panel terminal 14 of
connector I±24 is connected to battery.
5. If problem solved: GO TO CHECK TRANS
INDICATOR.
NO:Replace Powertrain Control Module (PCM).
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 27 of connector
I±24 is shorted to battery or open.
3. Verify if the indicator control unit connector B±16
terminal 20 is shorted to battery or open.
4. Verify that the instrument panel terminal 14 of
connector I±24 is connected to battery. If not,
check the fuses and the connections (terminal 7
of connector H±17) voltage.
Page 1700 of 2100
TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±13
5. If problem solved: GO TO CHECK TRANS
INDICATOR.
NO: Replace Powertrain Control Module (PCM).
D07R200003
Tech 2 OBD II Connection
In order to access OBD II Powertrain Control Module
(PCM) data, use of the Tech 2 scan tool kit (7000086) is
required.
1. The electronic diagnosis equipment is composed of:
1. Tech 2 hand held scan tool unit (7000057) and
DLC cable (3000095).
901RW176
2. SAE 16/19 adaptor (3000098) (1), RS 232 loop
back connector (3000112) (2), and PCMCIA card
(3000117) (3).
F07RW033
Page 1701 of 2100
7A1±14
TRANSMISSION CONTROL SYSTEM (4L30±E)
2. Connecting the TECH2
901RW180
Legend
(1) PCMCIA Card
(2) RS 232 Loop Back Connector(3) SAE 16/19 Adapter
(4) DLC Cable
(5) Tech 2
Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. The Isuzu 2002 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. Make sure the vehicle ignition is off.
Page 1702 of 2100
TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±15
5. Connect the Tech 2 SAE 16/19 adaptor to the
vehicle DLC.
826R200011
6. The vehicle ignition turns on.
7. Verify the Tech 2 power up display.
060RW009
NOTE: The RS232 Loop back connector is only to use for
diagnosis of Tech 2 and refer to
user guide of the Tech 2.
8. The power up screen is displayed when you
power up the tester with the Isuzu systems
PCMCIA card. Follow the operating procedure
below.
060R200032
Page 1703 of 2100
7A1±16
TRANSMISSION CONTROL SYSTEM (4L30±E)
060R200033
Once the test vehicle has been identified an ªApplication
(Powertrain) Menuº screen appears. Please select the
appropriate application.
The following table shows, which functions are used for
the available equipment versions.
F0: Diagnostic Trouble Codes
F0: Read DTC Info Ordered By Priority
F1: Clear DTC Information
F2: DTC Information
F1: Data Display
F0: Transmission Data
F2: Snap Shot
F3: Actuator Tests
F0: Lamps
F0: Check Light
F1: Winter Drive Lamp
F2: Power Drive Lamp
F3: AT Oil Temperature Lamp
F1: Solenoids
F0: Solenoid 1-2/3-4 Test
F1: Solenoid 2-3 Test
F2: TCC Solenoid
F3: Band Apply Solenoid
F4: Pressure Control Solenoid (PCS)
F4: Function Tests
F0: Reset Oil Life Monitor
Page 1704 of 2100

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±17
Diagnostic Trouble Codes
The purpose of the ªDiagnostic Trouble Codesº mode is to
display stored PCM trouble codes.
When ªDiagnostic Trouble Codesº is selected an
ªApplication Menuº screen appears.
Clear DTC Information
The purpose of the ªClear DTC Informationº mode is to
command the clearing of stored PCM trouble codes.
When ªClear DTC Informationº is selected, a ªClear DTC
Informationº, warning screen appears. This screen
informs you that by cleaning DTC's, ªall stored DTC
information in controller will be erasedº.
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 ªDTC Informationº is selected, an ªApplication
Menuº 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 ªData Displayº 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 ªData Displayº is selected an ªApplication Menuº
appears. Please select either ªEngineº or ªTransmission
Data Displayº.
See ªTransmission Dataº on next page.
Snapshot
When ªSnapshotº is selected an ªApplication Menuº
appears.
When ªTransmission Snapshotº application is selected
from the ªApplication Menuº, a ªSnapshot Menuº
appears, displaying several options. ªSnapshotº options
may vary from one system to another.
ªSnapshotº 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 ªActuator Testsº mode is to check for
correct operation of electronic system actuators.Lamps
You can operate the lamps by pressing the ON and OFF
buttons.
Preconditions: none
Solenoid
Solenoid 1-2/3-4, Solenoid 2-3, TCC Solenoid
You can operate the solenoids by pressing the ON and
OFF buttons.
Preconditions: P±N position, no vehicle speed, no engine
speed
Band Apply Solenoid
You can operate the solenoid by pressing the ON and
OFF buttons.
Preconditions: P-N position, idle engine speed, no vehicle
speed.
Pressure Control Solenoid (PCS)
You can set desired PCS Current using the ªIncrementº
(+25) and ªDecrementº (±25) button. The PC Solenoid
Data informs about PCS Current, Pressure and Duty
Cycle.
Preconditions: P±N position, no engine speed, no vehicle
speed
Reset Oil Life Monitor
Displays parameter ªOil Life Monitorº and resets to 100%
if Yes-button is pressed on Reset-question. ªNoº leaves
test.
Preconditions: no vehicle speed, no engine speed
NOTE:
Freeze Frame (Powertrain DTC A/B Type)
Freeze Frame is an element of the Diagnostic Manage-
ment System which stores various vehicle information at
the moment an emissions-related fault is stored in
memory and when the MIL is commanded on. These data
can help to identify the cause of a fault. Refer to
Storing
And Erasing Freeze Frame Data
for more detailed in-
formation.
Failure Records (Powertrain DTC C/D Type)
Failure Records data is an enhancement of the OBD II
Freeze Frame feature. Failure Records store the same
vehicle information as does Freeze Frame, but it will store
that information for any fault which is stored in on-board
memory, while Freeze Frame stores information only for
emission-related faults that command the MIL on.