1998 ISUZU TROOPER oil pressure

7A±58
AUTOMATIC TRANSMISSION (4L30±E)
Oil Pump
Disassembled View
241RS014
Legend
(1) Oil Pump Drive Gear
(2) Oil Pump Driven Gear
(3) Pin
(4) Plug
(5) Spring
(6) Converter Clutch Control Valve
(7) Snap Ring
(8) Spring Seat
(9) Spring(10) Throttle Signal Accumulator Piston
(11) Sleeve Pin
(12) Sleeve
(13) Boost Valve
(14) Spring Seat
(15) Valve Spring
(16) Spring Seat
(17) Pressure Regulator valve
(18) Oil Pump Assembly
Disassembly
1. Remove oil pump drive gear (1) and driven gear (2).
2. Remove pin (3) from oil pump assembly (18).
3. Remove plug (4), spring (5), and converter clutch
control valve (6).
4. Remove snap ring (7) from oil pump assembly (18).
5. Remove spring seat (8), spring (9), and throttle signal
accumulator piston (10).
6. Remove sleeve pin (11) from oil pump assembly (18).
7. Remove sleeve (12), boost valve (13), spring seat
(14), valve spring (15), spring seat (16), and pressure
regulator valve (17).
Inspection And Repair
Visual Check:
If any damage, deformation or wear is found, replace the
damaged part.
Reassembly
1. Lubricate and preinstall pressure regulator spring
seat (16) on valve (17), with the flat side against
shoulder.
2. Install pressure regulator valve (17) and spring seat
(16) assembly, valve spring (15), and spring seat (14)
with the flat side away from spring to oil pump
assembly (18).
3. Assemble boost valve (13) into sleeve (12).
4. Install boost valve and sleeve assembly, and sleeve
pin (11) to oil pump assembly (18).
5. Install throttle signal accumulator piston (10), spring
(9), and spring seat (8), with the flat side away from
the spring, and snap ring (7) to oil pump assembly
(18).
6. Install converter clutch control valve (6), spring (5),
plug (4), and pin (3) to oil pump assembly (18).
7. Install oil pump driven gear (2) and drive gear (1).

7A±60
AUTOMATIC TRANSMISSION (4L30±E)
10. Remove retainer (13), 2±3 shift valve (14), and spring
(15).
11. Remove spring pin (16), plug (17), spring (18), and
low pressure control valve (19).
12. Remove spring pin (20), plug (21), and band control
screen assembly (22).
13. Remove spring pin (23), plug (24), 1±2 accumulator
valve (25), and 1±2 accumulator control valve (26).
14. Remove check ball (27) from valve body (28).
Inspection And Repair
Inspect for the following, and replace any damaged or
worn parts:
1. Damage or wear to each valve.
2. Damage in oil passeges.
3. Cracks or damage to valve body.
4. Valve operations.
5. Spring fatigue.
Reassembly
1. Install 1±2 accumulator control valve (26), 1±2
accumulator valve (25), plug (24), and spring pin (23).
2. Install band control screen assembly (22), plug (21),
and spring pin (20).
3. Install low pressure control valve (19), spring (18),
plug (17), and spring pin (16).
4. Install spring (15), 2±3 shift valve (14), retainer (13),
solenoid B (12), and spring pin (11).
5. Install spring (10), 1±2/3±4 shift valve (9), retainer (8),
solenoid A (7), and spring pin (6).
6. Install waved washer (5), band control solenoid (3),
and pin (4).
7. Install manual valve (2).
8. Install check ball (27) to valve body (28).
9. Install gasket (valve body/transfer plate) and transfer
plate using two 5±8840±2270±0 (J±3387±2) guide
pins.

Install two 11mm bolts.
Torque: 13 Nwm (1.3 kg´m/113 lb in)
244RW004

Install gasket (transfer plate/main case).

7A±83 AUTOMATIC TRANSMISSION (4L30±E)
ILLUSTRATIONTOOL NO.
TOOL NAME
5±8840±2282±0
(J±36797)
A/T extension housing
oil seal installer (Inside)
5±8840±0003±0
(J±3289±20)
Holding fixture base
5±8840±0004±0
Pressure gauge
5±8840±0618±0
(J±24773±1)
End play fixture (Use
with 5±8840±2271±0
(J±25022))
5±8840±0019±0 &
5±8840±2000±0
(J±23907)
Slide hammer

7A±86
AUTOMATIC TRANSMISSION (4L30±E)
Pump Assembly
241RS019
Legend
(201) Gear, Oil Pump Drive
(202) Gear, Oil Pump Driven
(203) Pin, Boost Valve Sleeve
(204) Sleeve, Boost Valve
(205) Valve, Boost
(206) Seat, Spring/Pressure Regulator Valve
(207) Spring, Pressure Regulator Valve
(208) Valve, Pressure Regulator(209) Pump Assembly, Oil
(210) Valve, Converter Clutch Control
(211) Spring, Converter Clutch Control Valve
(212) Plug, Converter Clutch Control Valve
(213) Pin, Spring
(214) Piston, Throttle Signal Accumulator
(215) Spring, Throttle Signal Accumulator
(216) Seat, Spring/Throttle Signal Accumulator
(217) Ring, Snap/Throttle Signal Accumulator

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.

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±55
DTC P0748 Pressure Control Solenoid (PCS) (Force Motor) Circuit Electrical
StepActionYe sNo
11. Install the scan tool.
2. With the engine ªoffº, turn the ignition switch ªonº.
NOTE: Before clearing DTC(s), use the scan tool to record ªFailure
Recordsº for reference, as data will be lost when the ªClear Infoº
function is used.
3. Record the DTC ªFailure Recordsº.
4. While the engine is operating, put the transmission in Park.
5. Using the scan tool, apply 0.1 amp through 1.0 amp while
observing ªPC Ref. Currentº and ªPC Act. Currentº.
Is the ªPC Act. Currentº reading always within 0.16 amp?
Go to Diagnostic
Aids
Go to Step 2
21. Turn the ignition ªoffº.
2. Disconnect the transmission 5±way connector M±6.
3. Using the J39200 DVOM, measure the resistance between
terminals M6±2(B) and M6±1(E).
Is the resistance within 3±7 ohms?
Go to Step 6Go to Step 3
31. Remove the transmission oil pan. Refer to Solenoid (Adapter
Case Valve Body) in Automatic Transmission (4L30±E)
section.
2. Disconnect the internal wiring harness at the PCS.
3. Measure the resistance of the PCS.
Is the resistance within 3±7 ohms?
Go to Step 5Go to Step 4
4Replace the PCS.
Is the replacement complete?
Go to Step 9Ð
5Repair the internal wiring harness for an open.
Is the repair complete?
Go to Step 9Ð
6Inspect/repair circuits J3±E4, M6±2(B), J3±E3, and M6±1(E).
Was a problem found?
Go to Step 9Go to Step 7
7Inspect/repair circuits J3±E4, M6±2(B), J3±E3, and M6±1(E) for
a short to ground or poor connections.
Was a problem found?
Go to Step 9Go to Step 8
8Replace the PCM. Refer to Powertrain Control Module (PCM) in
Automatic Transmission (4L30±E) section.
Is the replacement complete?
Go to Step 9Ð
91. After the repair is complete, use the scan tool to select ªDTCº,
then ªClear Infoº function and ensure the following conditions
are met:
The PCS duty cycle is not at its electrical high or low limit.
2. Review the scan tool ªDTC Infoº.
Has the last test failed or is the current DTC displayed?
Begin diagnosis
again
Go to Step 1
Repair verified
Exit DTC table

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±67
DTC P1850 Brake Band Apply Solenoid Malfunction
D07RW009
Circuit Description

The brake band apply solenoid is a normally open
solenoid which controls the flow of fluid for brake band
application. The Powertrain Control Module (PCM)
uses Pulse Width Modulation (PWM) and changes
the duty cycle to control the solenoid. The PCM turns
the solenoid on (energized) and off (deenergized) at a
constant frequency. The length of time the solenoid is
energized during each on/off cycle is called the pulse
width. By varying or ªmodulatingº the pulse width, the
solenoid output pressure is changed. Since the
solenoid is normally open, increasing the pulse width
increases the duty cycle and decreases the output
pressure. PWM control provides smooth band
application without an accumulator. The band is only
applied in first and second gears.

In the event of an electrical failure (open), the
solenoid regulates at the maximum oil flow (0% duty
cycle).

The solenoid is activated by current. This current is
produced by applying a voltage to one side (the High
side) and a ground to the other side (Low side).

The High Side Driver (HSD) is a circuit of the PCM
that acts as a switch between the solenoids and the
supply voltage. The High side of the solenoid is
permanently supplied with voltage. When the ignition
is off, the HSD is turned off.This DTC detects a continuous open or short to ground in
the brake band apply solenoid circuit or the brake band
apply solenoid. This is a type ªDº DTC.
Conditions For Setting The DTC

Battery voltage is between 10 and 16 volts.

Ignition is ªonº, Engine ªrunº.

The PCM commands the solenoid ªonº and the
voltage remains high (B+) or the PCM commands the
solenoid ªoffº and the voltage remains low (zero
volts).

All conditions met in 1.3 seconds.
Action Taken When The DTC Sets

Inhibit brake band apply solenoid.

The PCM will not illuminate the CHECK TRANS
Lamp.
Conditions For Clearing The DTC

The DTC can be cleared from the PCM history by
using a scan tool.

The DTC will be cleared from history when the vehicle
has achieved 40 warmup cycles without a failure
reported.

The PCM will cancel the DTC default actions when
the fault no longer exists and the ignition is cycled ªoffº
long enough to power down the PCM.