ISUZU AXIOM 2002 Service Repair Manual

7A1±4
TRANSMISSION CONTROL SYSTEM (4L30±E)
Powertrain Control Module (PCM)
C07R200004

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±5
Control System Diagram
C07R100005

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
(Electronically Controlled Capacity Clutch
= ECCC)
The clutch apply is controlled by moving the converter
clutch valve by commanding Torque Converter Clutch
(TCC) solenoid using the PWM 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.
Reverse Lock Out Control
With the selector lever in reverse position, the PCM will
not close the PWM solenoid until the vehicle is below 11
km/h (6.8 mph), thus preventing reverse engagement
above this speed.
Downhill Control
This mode is automatically activated from ªNORMALº
mode only when downhill conditions are recognized.
The shift pattern is identical to ªNORMALº mode except
3-4 and 4-3 shift lines at low throttle modified to get engine
braking on a larger speed range.
ECCC lines unchanged compared to ªNORMALº mode.
Uphill Control
When Uphill condition are recognized the 2-3 and 3-4 shift
and TCC apply take place only when the engine torque is
sufficient in order to avoid shift hunting.

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±7
Shift Mode Control
F07RX001

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:
Conditions:
a. The select lever position is ªDº range only.
b. Vehicle speed is 7 mph (11 km/h) or less.
c. Transmission oil temperature is 130
C (266
F) or
less.
d. 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 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
130
C (266
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)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.

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

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.

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