ISUZU TROOPER 1998 Service Repair Manual

7A1±6
TRANSMISSION CONTROL SYSTEM (4L30±E)
Shift Control
The transmission gear is shifted according to the shift
pattern selected by the driver. In shifting gears, the gear
ratio is controlled by the ON/ OFF signal using the shift
solenoid A and the shift solenoid B.
Band Apply Control
The band apply is controlled when in the 3±2 downshift
(engine overrun prevention) and the garage shift (shock
control).
The band apply solenoid is controlled by the signal from
the Pulse Width Modulation (PWM) to regulate the flow of
the oil.
Torque Converter Clutch Control
The clutch ON/OFF is controlled by moving the converter
clutch valve through shifting Torque Converter Clutch
(TCC) solenoid using the ON/OFF signal.
Line Pressure Control
The throttle signal allows the current signal to be sent to
the force motor. After receiving the current signal, the
force motor activates the pressure regulator valve to
regulate the line pressure.
On±Board Diagnostic System
Several malfunction displays can be stored in the
Powertrain Control Module (PCM) memory, and read out
of it afterward.The serial data lines, which are required for the testing of
the final assembly and the coupling to other electronic
modules, can be regulated by this function.
Fail Safe Mechanism
If there is a problem in the transmission system, the PCM
will go into a ªbackupº mode.
The vehicle can still be driven, but the driver must use the
select lever to shift gears.
Torque Management Control
The transmission control side sends the absolute spark
advance signal to the engine control side while the
transmission is being shifted. This controls the engine
spark timing in compliance with the vehicle running
condition to reduce the shocks caused by the change of
speed.
ATF Warning Control
The oil temperature sensor detects the ATF oil
temperature to control the oil temperature warning, TCC,
and the winter mode.
ABS Control (If equipped)
When the select lever is at ªLº or ªRº range, a signal is sent
to the ABS controller as one of the ABS control
conditions.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±7
Shift Mode Control
C07RW079

7A1±8
TRANSMISSION CONTROL SYSTEM (4L30±E)
Gear Shift Control
F07RT034

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±9
Winter Drive Mode
1.Operation
The winter switch will operate when switched on after
all of the following conditions are present:
a. The gear select position is ªDº, ªNº, ªRº and ªPº
range.
b. Vehicle speed is 7 mph (11 km/h) or less.
c. Transmission oil temperature is 120
C (248
F) or
less.
d. Kickdown switch is off.
e. Accelerator opening is at 8% or less.
2.Cancel Release
1. Cancellation by driver
a. Turning off the winter drive mode switch
b. Shifting select position to ª3º, ª2º, or ªLº (Winter
drive mode is not canceled by selecting ªDº, ªNº,
ªRº, or ªPº)
c. Ignition key is turned off.
2. Automatic cancellation
a. When vehicle runs at 21mph (34 km/h) or more
for 1 second or more
b. When transmission oil temperature reaches
140
C (284
F) or above
NOTE: The mode returns to normal drive mode or power
drive mode after the winter drive 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 Powertrain Control Module (PCM).
The ªCHECK TRANSº light flashes to alert the driver, and
the transmission must be manually shifted as follows:
Select lever position
Gear Ratio Selected
D4 (Fourth)
Manual 34 (Fourth)
Manual 23 (Third)
Manual L1 (First)
RReverse
Shifts are firmer to prevent clutch slip and consequent
wear. The fault should be corrected as soon as possible.

7A1±10
TRANSMISSION CONTROL SYSTEM (4L30±E)
Functions of Input / Output Components
ComponentsFunction
Speed sensor
(fixed to transmission
(T/M))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 (SW)
(fixed to brake pedal)Senses whether the driver has pressed the brake pedal or not and feeds the
information to PCM.
N-
P
U
Kickdown SW
(fixed to accelerator pedal)Senses whether the driver has pushed the accelerator pedal fully or not, and
feeds the information to PCM.
U
TMode SW (fixed to T/M)Senses the select lever position, and feeds the information to PCM.

S
I
Power drive SW
(fixed to front console)Senses whether the driver has selected the power mode, and feeds the informa-
tion to PCM.
I
G-T/M oil temp. sensorSenses the T/M oil temperature and feeds the data to PCM
N
A
L
Engine coolant tempera-
ture sensorSenses the engine coolant temperature, and feeds the data to PCM.
LEngine speed signalFeeds the signals monitoring engine speed to PCM from crank angle sensor.
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 informa-
tion to PCM.
Cruise controller * (Over-
drive OFF signal)Downshift takes place when Overdrive OFF signal is received from auto cruise
control unit.
S
Shift solenoid A, BSelects shift point and gear position suited to the vehicle running condition on
the basis of PCM output.
O
S
O-
L
Band apply solenoidControls oil flow suited to the vehicle running condition on the basis of PCM out-
put.
O
U
T-
P
E-
N
O
Torque Converter
Clutch solenoidControls clutch engagement/disengagement suited to the vehicle running condi-
tion on the basis of PCM output.
P
U
T

O
I
DForce motor
(Pressure regulator
valve)Adjusts the oil pump delivery pressure to line pressure suited to the vehicle run-
ning condition on the basis of PCM output.

S
I
Power drive mode lampInforms the driver whether the vehicle is in power mode or not.
I
G-Winter drive mode lampInforms the driver whether the vehicle is in winter mode or not.G
N
A
L
T/M monitor lamp
(ªCHECK TRANSº)Informs the driver of failure in the system.
LATF warning lampLights when ATF oil temperature rises.
ABS signal *When the select lever is at ªReverseº or ªLº range, sends a signal to the ABS
controller as one of the ABS control conditions.
* If equipped

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 GOTO ªSECTIONº means to continue to check
going to the ªsectionº.
4. The GOTHROUGH ªSECTIONº means to go
through the ªsectionº and then to go back to the place
the GOTHROUGH 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: GOTO DIAGNOSTIC CHECK.
B. Staying on: GOTHROUGH CHECK TRANS
CHECK.
C. Is never ON when the ignition key is turned on:
GOTHROUGH CHECK TRANS CHECK
D. Is ON during 2 to 3 seconds at ignition but OFF after:
Normal operation. No DTC or malfunction.
821RW261
Diagnostic Check
This test determines if the transmission or its inputs,
outputs, connections, or sensors are failing.
1. Connect the Tech2: GOTHROUGH Tech2 OBD II
CONNECTION.
2. Turn on the ignition but not the engine.3. Push ªF2º on Tech2 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. GOTHROUGH 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 GOTO
DIAGNOSTIC CHECK and if you find the same
problem, replace the Powertrain Control Module
(PCM).
Normal
C07RW047
Abnormal
C07RW048

7A1±12
TRANSMISSION CONTROL SYSTEM (4L30±E)
ªCheck Transº Check
1. Indicator it is ON during 2 to 3 seconds at ignition (or
when the engine is cranked) but it is OFF after the
engine starts. The indicator is working normally
GOTO DIAGNOSTIC CHECK.
821RW261
Normal
C07RW047
2. Indicator it 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. GOTO DIAGNOSTICAbnormal
C07RW048
3. Indicator it is staying ON always when Ignition is ON.
1. This means that connection between the lamp
and the PCM is shorted to ground.
2. Verify if instrument panel terminal 3 of connector
I±9 is shorted to ground.
3. Verify if the PCM connector J1 (RED) terminal
A14 is shorted to ground.
4. Verify that the instrument panel terminal 15 of
connector I±9 is connected to battery.
5. IF problem solved: GOTO CHECK TRANS
INDICATOR.
NO:Replace Powertrain Control Module (PCM).
4. Indicator it is staying OFF with the ignition ON (engine
OFF).
1. This means that connection between the lamp
and the PCM is shorted to battery or opened.
2. Verify if instrument panel terminal 3 of connector
I±9 is shorted to battery or open.
3. Verify if the PCM connector J1 (RED) terminal
A14 is shorted to battery or open.
4. Verify that the instrument panel terminal 15 of
connector I±9 is connected to battery. If not,
check the fuses and the connections voltage.
5. IF problem solved: GOTO CHECK TRANS
INDICATOR.
NO: Replace Powertrain Control Module (PCM).

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±13
D07RW028
Tech2 OBD II Connection
In order to access OBD II Powertrain Control Module
(PCM) data, use of the Tech2 scan tool is required.
1. The electronic diagnosis equipment is composed of:
1. Tech2 (3000094) hand±held scan tool, and DLC
cable (3000095).
901RW176
2. SAE 16/19 adapter (3000098) (1), RS 232 loop
back connector (3000112) (2), and PCMCIA card
(3000117) (3).
F07RW033

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) Tech2

Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. The Isuzu 98 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.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±15
5. Connect the Tech 2 SAE 16/19 adaptor to the
vehicle DLC.
821RW262
821RW263
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.