1998 ISUZU TROOPER controls

6E±105 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0204 (Flash DTC 54)
Injector # 4 Circuit Fault
060RW134
Circuit Description
The Engine Control Module ECM has four individual
injector driver circuits. Each controls an injector. When
the driver circuit is grounded by the ECM, the injector is
activated. The ECM monitors the current in each driver
circuit. The voltage on each driver is monitored to detect
a fault. If the voltage is not what the ECM expects to
monitor on the circuit, a DTC is set. This DTC is also set if
an injector driver is shorted to voltage or if there is an open
circuit.
Action Taken When the DTC Sets

The ECM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

DTC P0204 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the ECM battery
feed.
Diagnostic Aids
An injector driver circuit that is open or shorted to voltage
will cause a DTC P0204 to set.
Test Description
The number(s) below refer to the step number(s) on the
Diagnostic Chart.3. This step determines if DTC P0204 is the result of a
hard failure or an intermittent condition.
Injector Test
This test is conducted to make it sure that appropriate
electric signals are being sent to injectors Nos. 1±4.
Tech±2 must be used for this test.
Test Procedure:
1. Connect Tech±2 to the vehicle DLC.
2. Set Ignition Switch to the ªONº position.
3. Select Control Test.
4. Select Injector Test.
5. Send instructions to each injector (Switch on),
making sure of injector working noise.
NOTE: If injector working noise (Clink) can hardly be
confirmed, remove the engine head cover noise
insulation.
Refer to Section 6A.
6. In the injector whose working noise has been
confirmed, its electric circuit can be regarded as
normal.
As for the injector whose working noise has not
been confirmed, its electric circuit or the injector
proper is faulty.

6E±225 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
General Description
(ECM and Sensors)
57X Reference ECM Input
The engine control module (ECM) uses this signal from
the crankshaft position (CKP) sensor to calculate engine
RPM and crankshaft position at all engine speeds. The
ECM also uses the pulses on this circuit to initiate injector
pulses. If the ECM receives no pulses on this circuit, DTC
P0337 will set. The engine will not start and run without
using the 57X reference signal.
A/C Request Signal
This signal tells the ECM when the A/C mode is selected
at the A/C control head.
Refer to
A/C Clutch Circuit Diagnosis for A/C wiring
diagrams and diagnosis for the A/C electrical system.
Crankshaft Position (CKP) Sensor
The crankshaft position (CKP) sensor provides a signal
used by the engine control module (ECM) to calculate the
ignition sequence. The CKP sensor initiates the 57X
reference pulses which the ECM uses to calculate RPM
and crankshaft position.
Refer to
Electronic Ignition System for additional
information.
Camshaft Position (CMP) Sensor and
Signal
The camshaft position (CMP) sensor sends a CMP signal
to the ECM. The ECM uses this signal as a ªcylinder
distinctionº to trigger the injectors in the power order. If the
ECM detects an incorrect CMP signal while the engine is
running, DTC P0341 will set, and the ECM triggers the
injectors in the power order.
Refer to
DTC P0341.
Engine Coolant Temperature (ECT) Sensor
The engine coolant temperature (ECT) sensor is a
thermistor (a resistor which changes value based on
temperature) mounted in the engine coolant stream. Low
coolant temperature produces a high resistance of
100,000 ohms at ±40
C (±40
F). High temperature
causes a low resistance of 70 ohms at 130
C (266
F).
The ECM supplies a 5-volt signal to the ECT sensor
through resistors in the ECM and measures the voltage.
The signal voltage will be high when the engine is cold and
low when the engine is hot. By measuring the voltage, the
ECM calculates the engine coolant temperature. Engine
coolant temperature affects most of the systems that the
ECM controls.
The Tech 2 displays engine coolant temperature in
degrees. After engine start-up, the temperature should
rise steadily to about 85
C (185
F). It then stabilizes
when the thermostat opens. If the engine has not been
run for several hours (overnight), the engine coolanttemperature and intake air temperature displays should
be close to each other. A hard fault in the engine coolant
sensor circuit will set DTC P0117 or DTC P0118.
0016
Electrically Erasable Programmable Read
Only Memory (EEPROM)
The electrically erasable programmable read only
memory (EEPROM) is a permanent memory chip that is
physically soldered within the ECM. The EEPROM
contains the program and the calibration information that
the ECM needs to control powertrain operation.
Unlike the PROM used in past applications, the EEPROM
is not replaceable. If the ECM is replaced, the new ECM
will need to be programmed. Equipment containing the
correct program and calibration for the vehicle is required
to program the ECM.
Intake Air Temperature (IAT) Sensor
The intake air temperature (IAT) sensor is a thermistor
which changes its resistance based on the temperature of
air entering the engine. Low temperature produces a high
resistance of 100,000 ohms at ±40
C (±40
F). High
temperature causes low resistance of 70 ohms at 130
C
(266
F) . The ECM supplies a 5-volt signal to the sensor
through a resistor in the ECM and monitors the signal
voltage. The voltage will be high when the incoming air is
cold. The voltage will be low when the incoming air is hot.
By measuring the voltage, the ECM calculates the
incoming air temperature.
The Tech 2 displays the temperature of the air entering
the engine. The temperature should read close to the
ambient air temperature when the engine is cold and rise
as underhood temperature increases. If the engine has
not been run for several hours (overnight), the IAT sensor
temperature and engine coolant temperature should read
close to each other. A fault in the IAT sensor circuit will set
DTC P0112 or DTC P0113.

6E±226
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
0018
Manifold Absolute Pressure (MAP) Sensor
The manifold absolute pressure (MAP) sensor responds
to changes in intake manifold pressure. The MAP sensor
signal voltage to the ECM varies from below 2 volts at idle
(high vacuum) to above 4 volts.
The MAP sensor is used to determine the following:

Boost pressure for injector control.

Barometric pressure (BARO).
If the ECM detects a voltage that is lower than the
possible range of the MAP sensor, DTC P0107 will be set.
A signal voltage higher than the possible range of the
sensor will set DTC P0108. An intermittent low or high
voltage will set DTC P1107 or DTC P1106, respectively.
The ECM can detect a shifted MAP sensor. The ECM
compares the MAP sensor signal to a calculated MAP
based on throttle position and various engine load factors.
If the ECM detects a MAP signal that varies excessively
above or below the calculated value, DTC P0106 will set.
Engine Control Module (ECM)
The engine control module (ECM) is located in the engine
room.
The ECM constantly observes the information from
various sensors. The ECM controls the systems that
affect vehicle performance. The ECM performs the
diagnostic function of the system. It can recognize
operational problems, alert the driver through the MIL
(Service Engine Soon lamp), and store diagnostic trouble
codes (DTCs). DTCs identify the problem areas to aid the
technician in making repairs.
ECM Function
The ECM supplies 5, 12 and 110 volts to power various
sensors or switches. The power is supplied through
resistances in the ECM which are so high in value that a
test light will not light when connected to the circuit. In
some cases, even an ordinary shop voltmeter will not give
an accurate reading because its resistance is too low.
Therefore, a digital voltmeter with at least 10 megohms
input impedance is required to ensure accurate voltage
readings. The ECM controls output circuits such as theinjectors, glow relays, etc., by controlling the ground or
the power feed circuit through transistors or through
either of the following two devices:

Output Driver Module (ODM)

Quad Driver Module (QDM)
ECM Components
The ECM is designed to maintain exhaust emission levels
to government mandated standards while providing
excellent driveability and fuel efficiency. The ECM
monitors numerous engine and vehicle functions via
electronic sensors such as the crankshaft position (CKP)
sensor, and vehicle speed sensor (VSS). The ECM also
controls certain engine operations through the following:

Fuel injector control

Rail pressure control
ECM Voltage Description
The ECM supplies a buffered voltage to various switches
and sensors. It can do this because resistance in the
ECM is so high in value that a test light may not illuminate
when connected to the circuit. An ordinary shop
voltmeter may not give an accurate reading because the
voltmeter input impedance is too low. Use a 10-megohm
input impedance digital voltmeter to assure accurate
voltage readings.
The input/output devices in the ECM include
analog-to-digital converters, signal buffers, counters,
and special drivers. The ECM controls most components
with electronic switches which complete a ground circuit
when turned ªON.º These switches are arranged in
groups of 4 and 7, called either a surface-mounted quad
driver module (QDM), which can independently control up
to 4 output terminals, or QDMs which can independently
control up to 7 outputs. Not all outputs are always used.
ECM Input/Outputs
Inputs ± Operating Conditions Read

Air Conditioning ªONº or ªOFFº

Engine Coolant Temperature

Crankshaft Position

Electronic Ignition

Manifold Absolute Pressure

Battery Voltage

Intake Throttle Position

Vehicle Speed

Fuel Temperature

Oil Temperature

Intake Air Temperature

EGR boost pressure

Oil rail pressure

Camshaft Position

Accelerator position
Outputs ± Systems Controlled

Exhaust Gas Recirculation (EGR)

Injector Control

QWS

6E±228
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
General Description (Air Induction)
Air Induction System
The air induction system filters contaminants from the
outside air, and directs the progress of the air as it is
drawn into the engine. A remote-mounted air cleaner
prevents dirt and debris in the air from entering the
engine. The air duct assembly routes filtered air to the
throttle body. Air enters the engine by to following steps:
1. Through the throttle body.
2. Into the intake manifold.
3. Through the cylinder head intake ports.
4. Into the cylinders.
General Description (Fuel Metering)
Deceleration Mode
The ECM reduces the amount of fuel injected when it
detects a decrease in the Accelerator position.
Fuel Injector
Fuel injector comprises the solenoid, hydraulic line, and
fuel line. Fuel injection is controlled by the continuity time
signal and continuity start timing signal from ECM to the
solenoid
ECM determines the running conditions of engine by
input signals such as engine speed. Accelerator throttle
valve opening, and engine coolant temperature, thereby
to send the solenoid the best suited signal to the engine
status. When current is carried to the solenoid, the
armature opens the poppet valve to alow high pressure oil
to run into the injector. Under the pressure of the oil, the
piston and plunger are depressed to compress the fuel in
the combustion chamber of the plunger. Specifically, the
pressure of the fuel compressed is increased by a piston
top/ plunger bottom area ratio over the pressure of high
pressure oil, thereby lifting the fuel nozzle end needle for
injecting fuel.
Fuel Metering System Components
The fuel metering system is made up of the following
parts:

The fuel injectors.

The intake throttle body.

The Accelerator position (AP) sensor

The ECM.

The crankshaft position (CKP) sensor.

The camshaft position (CMP) sensor.
Basic System Operation
Fuel is supplied through fuel filter to the fuel pump.
The fuel pump is installed to the oil pump, and fuel is
forced, through the fuel pump outlet, pipe and cylinder
head inside, into the fuel injector.
An orifice is provided at the rear fuel outlet of cylinder
head to control the pressure of oil.The injector is controlled by ECM which gives
opening/closing commands to the solenoid installed on
the top of the injector. Opening/closing operation of the
pressurized engine oil circuit of the injector controls fuel
injection quantity, fuel injection timing, etc.
A/C Clutch Diagnosis
A/C Request Signal
This signal tells the ECM when the A/C mode is selected
at the A/C control head. The ECM uses this to adjust the
idle speed.
Refer to
A/C Clutch Circuit Diagnosis for A/C wiring
diagrams and diagnosis for A/C electrical system.
General Description Exhaust Gas
Recirculation (EGR) System
EGR Purpose
The exhaust gas recirculation (EGR) system is use to
reduce emission levels of oxides of nitrogen (NOx). NOx
emission levels are caused by a high combustion
temperature. The EGR system lowers the NOx emission
levels by decreasing the combustion temperature.
The ECM uses information from the following sensors to
control EGR valve boost pressure.

ECT

ITP

Engine Speed

AP sensor

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±21
NOTE: To use the DTC again to identify a problem, you
will need to reproduce the fault or the problem. This may
require a new test drive or just turning the ignition on (this
depends on the nature of the fault).
1. IF you have a Tech2:
1. Connect the Tech2 if it is still not connected
GOTHROUGH Tech2 OBD II CONNECTION.
2. Push ªF4º and answer ªYesº to the question ªDo
you really want to clear the codes?º
a. When a malfunction remains as it is the Tech2
displays ª4L30E CODES NOT CLEAREDº. This
means that the problem is still there or that the
recovery was not done. Please GOTO DTC
CHECK.
b. When a malfunction has been repaired and the
recovery is done. The Tech2 displays ª4L30E
CODES CLEAREDº.
2. IF you have no Tech2:
To clear the DTC, remove Fuse ªStop, A/T CONTº
(C±14, 15A) for at least 10 seconds.
DTC Check
1. Diagnostic Trouble Codes (DTC) have been identified
by Tech2.
2. You have written the list of the DTCs. The order of the
malfunctions has no meanings for this PCM. Usually
only one or two malfunctions should be set for a given
problem.
3. Check directly the DTCs you identified. The DTCs are
sorted by number. Refer to Diagnostic Trouble Code
(DTC) Identification in this section.
PCM Precaution
The PCM can be damaged by:
1. Electrostatic discharge
2. The short circuit of some terminals to voltage or to
ground.
Electrostatic Discharge Damage Description:
1. Electronic components used to control systems are
often designed to carry very low voltage, and are very
susceptible to damage caused by electrostatic
discharge. It is possible for less than 100 volts of
static electricity to cause damage to some electronic
components. By comparison, it takes as much as
4,000 volts for a person to even feel the zap of a static
discharge.2. There are several ways for a person to become
statically charged. The most common methods of
charging are by friction and induction. An example of
charging by friction is a person sliding across a car
seat, in which a charge of as much as 25,000 volts
can build up. Charging by induction occurs when a
person with well insulated shoes stands near a highly
charged object and momentarily touches ground.
Charges for the same polarity are drained off, leaving
the person highly charged with the opposite polarity.
Static charges of either type can cause damage,
therefore, it is important to use care when handling
and testing electronic components.
NOTICE: To prevent possible electrostatic
discharge damage:
1. Do not touch the PCM connector pins or soldered
components on the PCM circuit board.
2. Be sure to follow the guidelines listed below if
servicing any of these electronic components:
3. Do not open the replacement part package until it is
time to install the part.
4. Avoid touching electrical terminals of the part.
5. Before removing the part from its package, ground
the package to a known good ground on the vehicle.
6. Always touch a known good ground before handling
the part. This step should be repeated before
installing the part if the part has been handled while
sliding across the seat, while sitting down from a
standing position or while walking some distance.
Information On PCM
1. The Powertrain Control Module (PCM) is located in
the center console and is the control center of the
electronic transmission control system.
2. The PCM must be maintained at a temperature below
185
F (85
C) at all times. This is most essential if the
vehicle is put through a paint baking process. The
PCM will become inoperative if its temperature
exceeds 85
C (185
F). Therefore, it is
recommended that the PCM be removed or that
temporary insulation be placed around the PCM
during the time the vehicle is in a paint oven or other
high temperature process.
3. The PCM is designed to process the various inputs
and then respond by sending the appropriate
electrical signals to control transmission upshift,
downshift, shift feel and torque converter clutch
engagement.
4. The PCM constantly interprets information from the
various sensors, and controls the systems that affect
transmission and vehicle performance. By analyzing
operational problems, the PCM is able to perform a
diagnostic function by displaying DTC(s) and aid the
technician in making repairs.
Intermittent Conditions
If the Tech2 displays a diagnostic trouble code as
intermittent, or if after a test drive a DTC does not
reappear though the detection conditions for this DTC are
present, the problem is most likely a faulty electrical

TRANSMISSION CONTROL SYSTEM (4L30±E)7A1±25
DTC P0218 Transmission Fluid Over Temperature
D07RW029
Circuit Description
The Transmission Fluid Temperature (TFT) sensor is a
thermister that controls the signal voltage to the PCM.
The PCM supplies a 5±volt reference to the sensor on
circuit RED/BLK±GRN/RED. When the transmission fluid
is cold, the sensor resistance is high and the PCM will
sense high signal voltage. As the fluid temperature
warms to a normal transmission operating temperature of
100
C (212
F), the sensor resistance becomes less and
the voltage decreases to 1.5 to 2.0 volts.
This DTC detects a high transmission temperature for a
long period of time. This is a type ªDº DTC.
Conditions For Setting The DTC

No TFT DTCs P0712 or P0713.

TFT is greater than 135
C (275
F).

All conditions met for 21 seconds.
Action Taken When The DTC Sets

Hot mode TCC Shift Pattern.

The PCM will not illuminate the CHECK TRANS
Lamp.

ATF Lamp ON. (TFT is greater than 145
C (293
F).)

Disable E±side TCC OFF request.
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 warm±up 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.
Diagnostic Aids

Inspect the wiring for poor electrical connections at
the PCM and at the transmission 16±way connector.
Look for possible bent, backed out, deformed, or
damaged terminals. Check for weak terminal tension
as well.
Also check for a chafed wire that could short to bare
metal or other wiring. Inspect for a broken wire inside
the insulation.

When diagnosing for a possible intermittent short or
open condition, move the wiring harness while
observing test equipment for a change.

Check harness routing for a potential short to ground
in circuit RED/BLK±GRN/RED.

Scan tool TFT sensor temperature should rise
steadily to about 100
C (212
F), then stabilize.

Check for a ªskewedº (mis±scaled) sensor by
comparing the TFT sensor temperature to the
ambient temperature after a vehicle cold soak. A
ªskewedº sensor can cause delayed garage shifts or
TCC complaints.

Check for a possible torque converter stator problem.

Verify customer driving habits, trailer towing, etc.
Test Description
The numbers below refer to the step numbers on the
diagnostic chart.
3. This test checks for a ªskewedº sensor or shorted
circuit.
4. This test simulates a TFT DTC P0713.