1998 ISUZU TROOPER check engine

7A±16
AUTOMATIC TRANSMISSION (4L30±E)
Chart 6: Diagnostic Trouble Code (DTC) P0730
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15b:
Possible Causes
of High Line
Pressure in this
section
21. 1st and 2nd gear missing or 3rd and 4th gear missing.
Check appropriate shift valve. If OK replace solenoid.
2. No engine brake in any range (All ranges in Drive and Reverse
are OK).
Check for suspected conditions modifying delays to clutch
apply:
± Overrun clutch seal damaged.
± Excessive overrun clutch piston travel.
± Defective 3±4 accumulator piston.
± Causes of internal leaks.
± Causes of burned clutch plates.
3. 1st and 4th gear missing or 2nd and 3rd gear missing.
Shift solenoid A stuck. Replace shift solenoid A.
4. DTC P0730 is set in D range 1st gear above 3500 rpm.
Go to Step 3.
5. DTC P0730 is set in D range 3rd gear between 55-80 mph.
NOTE: Perform this test within safe and legal limits.
Check for suspected conditions modifying delays to clutch
apply:
± 4th clutch seal damaged.
± Excessive 4th clutch piston travel.
± Defective 3±4 accumulator piston.
± Causes of internal leaks.
± Causes of burned clutch plates.
Was the problem found?
Repair or replaceÐ
3Check 3rd gear in ªDº in winter mode.
Does vehicle move?Shift solenoid A
stuck. Replace
shift solenoid A.
Go to Step 4
4Check for suspected conditions modifying delays to clutch apply:
± 2nd clutch seal damaged.
± Excessive 2nd clutch piston travel.
± Defective accumulator piston.
± Causes of internal leaks.
± Check ball missing or out of location in 2nd clutch.
± Seals cut, damaged or missing.
± Gaskets defective.
± Causes of burned clutch plates.
Was the problem found?
Repair or replaceÐ

7A±18
AUTOMATIC TRANSMISSION (4L30±E)
Chart 9c: Coastdown Harsh Shift Or Clunk At 3±2 Downshift
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15b:
Possible Causes
of High Line
Pressure in this
section
2Does DTC P1850 set?
Diagnose P1850
first
Replace band
apply solenoid
(PWM) (323)
Chart 10: Intermittent 4TH TO 2ND Gear Downshift At Steady Speed
StepActionYe sNo
1Check for consistent speed sensor reading with scan tool.
Was the reading correct?Replace mode
switch for
intermittent
contact.
Go to Step 2
21. Check for wiring harness damage or short to ground. If OK, go
to (2).
2. Check transmission speed sensor connections. If OK, go to
(3).
3. Replace transmission speed sensor.
Was the replacement complete?
Ð
Replace speed
sensor.
Chart 11: Engine Flare At Shifting During Turning Only (Usually With Warm Engine)
StepActionYe sNo
1Check for oil leaks at transmission.
Was the problem found?Replace
transmission oil
filter and gasket
Ð
Chart 12: Engine Flare During 1±2 Or 2±3 Shift
StepActionYe sNo
1Check line pressure. Refer to Line Pressure Test in this section.
Was line pressure normal?
Go to Step 2
Use Chart 15a:
Possible Causes
of Low Line
Pressure in this
section
21. Check for a stuck 1±2 accumulator valve (320).
2. Check for servo piston (106) leaks.
3. Check for a stuck band apply solenoid (323).
Was line pressure normal?
Repair or replaceÐ

7A±22
AUTOMATIC TRANSMISSION (4L30±E)
Chart 16: Possible Causes Of
Transmission Fluid Leaks
Before attempting to correct an oil leak, the actual source
of the leak must be determined. In many cases, the
source of the leak may be difficult to determine due to
ªwind flowº around the engine and transmission.
The suspected area should be wiped clean before in-
specting for the source of the leak.Oil leaks around the engine and transmission are gener-
ally carried toward the rear of the vehicle by the air
stream. In determining the source of an leak, the following
two checks should be made:
1. With the engine running, check for external line
pressure leaks.
2. With the engine off, check for oil leaks due to the
raised oil level caused by drainback of converter oil
into the transmission.
Possible Causes Of Fluid Leaks Due To Sealing Malfunction
240RS002
Legend
(1) Electrical Connector (Main Case) Seal
(2) Transmission Vent (Breather)
(3) Speed Sensor O±Ring
(4) Extension (Adapter) Lip Seal
(5) Extension (Adapter) to Main Case Gasket
(6) Oil Drain Plug Gasket
(7) Oil Pan Gasket (Main Case)
(8) Selector Shaft Seal(9) Oil Cooler Connectors (2)
(10) Oil Pan Gasket (Adapter Case)
(11) Converter housing attaching bolts not correctly
torqued
(12) Converter Housing Lip Seal
(13) Line Pressure Tap Plug
(14) Electrical Connector (Adapter Case) Seal
(15) Adapter Case Seal Rings (2)

7A±23 AUTOMATIC TRANSMISSION (4L30±E)
Stall Test
The stall test allows you to check the transmission for
internal abrasion and the one way clutch for slippage.
Torque converter performance can also be evaluated.
The stall test results together with the road test results will
identify transmission components requiring servicing or
adjustment.
Stall Test Procedure:
1. Check the level of the engine coolant, the engine oil,
and the automatic transmission fluid. Replenish if
necessary.
2. Block the wheels and set the parking brake.
3. Connect a tachometer to the engine.
4. Start the engine and allow it to idle until the engine
coolant temperature reaches 70 ± 80
C (158 ±
176
F).
5. Hold the brake pedal down as far as it will go.
6. Place the selector in the ªDº range.
7. Gradually push the accelerator pedal to the floor.
The throttle valve will be fully open.
Note the engine speed at which the tachometer
needle stabilizes.
Stall Speed : 2,100 +150 rpm
NOTE: Do not continuously run this test longer than 5
seconds.
8. Release the accelerator pedal.
9. Place the selector in the ªNº range.
10. Run the engine at 1,200 rpm for one minute.
This will cool the transmission fluid.
11. Repeat Steps 7 ± 10 for the ª3º, ª2º, ªLº and ªRº
ranges.
Line Pressure Test
The line pressure test checks oil pump and control valve
pressure regulator valve function. It will also detect oil
leakage.
Line Pressure Test Procedure:
1. Check the level of the engine coolant, the engine oil,
and the automatic transmission fluid.
Replenish if required.
2. Block the wheels and set the parking brake.
3. Remove the pressure detection plug at the left side of
the transmission case.
Set 5±8840±0004±0 pressure gauge and adapter to
the pressure detection plug hole.
241RS001
4. Start the engine and allow it to idle until the engine
coolant temperature reaches 70 ± 80
C (158 ±
176
F).
5. Hold the brake pedal down as far as it will go.
6. Place the selector in the ªDº range.
7. Note the pressure gauge reading with the engine
idling.
8. Gradually push the accelerator pedal to the floor. The
throttle valve will be fully open.
Note the pressure gauge reading with the accelerator
pedal fully depressed.
NOTE: Do not continuously run this test longer than 5
seconds.
9. Release the accelerator pedal.
10. Place the selector in the ªNº range.
11. Run the engine at 1,200 rpm for one minute.
This will cool the transmission fluid.
12. Repeat Steps 7 ± 11 for the ª3º, ª2º, ªLº, and ªRº
ranges.
13. Install a pressure detection plug to the transmission
case, applying recommended thread locking agent
(LOCTITE 242) or its equivalent to thread of plug.
Make sure that thread is cleaned before applying
locking agents.
14. Tighten the pressure detection plug to the specified
torque.
Torque: 9 ± 14N´m (0.9 ± 1.4 kg´m/7 ± 10 lb ft)

7A±27 AUTOMATIC TRANSMISSION (4L30±E)
Changing Transmission Fluid
There is no need to change the transmission fluid unless
the transmission is used under one or more of the
following heavy duty conditions.
A. Repeated short trips
B. Driving on rough roads
C. Driving on dusty roads
D. Towing a trailer
If the vehicle is used under these conditions, change the
fluid every 20,000 miles (32,000 km.)
More over, the remaining life percentage of ATF can be
estimated by using Tech 2 as an auxiliary tool to judge the
right time for ATF replacement.
The remaining life percentage is calculated from ATF'S
heat history. When it is close to 0%, ATF replacement is
recommended.
1. Place a large drain pan under the oil pan.
2. Remove the transmission oil drain screw (2) and drain
fluid.
3. Tighten drain screw (2).
Torque: 38 Nwm (3.9 kg´m/28 lb ft)
4. Remove the transmission overfill screw (1) and fill
transmission through overfill screw opening, using
DEXRON)±III ATF.
NOTE: Add transmission fluid until it flows out over the
overfill screw opening.
5. Let engine idle until a fluid temperature between 32
C
(90
F) and 57
C (135
F) is reached.6. Add transmission fluid until it flows out over the overfill
screw opening, then close the overfill screw (1).
Torque: 38 Nwm (3.9 kg´m/28 lb ft)
NOTE: To prevent fluid leaks, the overfill screw and oil
drain screws gasket must be replaced each time these
screws are removed.
NOTE: C h e c k t r a n s mission fluid temperature with
service scan tool.
242RW003
Selector Lever
Inspection
1. Make sure that when the shifter control lever is shifted
from ªPº to ªLº, a ªclickingº can be felt at each shift
position. Make sure that the gear corresponds to that
of the position plate indicator.
2. Check to see if the shifter lever can be shifted as
shown in illustration.
C07RW009

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).