ISUZU TROOPER 1998 Service Repair Manual

6E±218
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
2. Disconnect the EGR VSV connector and vacuum
hose from the EGR VSV.
035RW063
3. Remove the MAP sensor assembly and EGR VSV.
035RW067
4. Remove the EGR VSV from the MAP sensor bracket.
035RW062
Installation Procedure
1. Install the EGR VSV and tighten nut to specified
torque.
Torque: 8 N´m (69 lb in)
035RW062

6E±219 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
2. Install the MAP sensor assembly and EGR VSV and
tighten MAP sensor bracket fixing bolts specified
torque.
Torque: 9 N´m (78 lb in)
035RW067
3. Connect the EGR VSV connector and vacuum hose
in the EGR VSV.
035RW063
4. Connect the negative battery cable.
Electronic Vacuum Regurating
Valve (EVRV)
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the EVRV hose and the EVRV connector.
035RW065
3. Remove the EVRV.
035RW064

6E±220
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Installation Procedure
1. Install the EVRV.
035RW064
2. Connect the EVRV hose and the EVRV connector.
035RW065
3. Connect the negative battery cable.
Wiring and Connectors
Wiring Harness Service
The ECM harness electrically connects the ECM to the
various solenoids, switches and sensors in the vehicle
engine compartment and passenger compartment.
Replace wire harnesses with the proper part number
replacement.
Because of the low amperage and voltage levels utilized
in powertrain control systems, it is essential that all wiring
in environmentally exposed areas be repaired with crimp
and seal splice sleeves.The following wire harness repair information is intended
as a general guideline only. Refer to
Chassis Electrical for
all wire harness repair procedures.
Connectors and Terminals
Use care when probing a connector and when replacing
terminals. It is possible to short between opposite
terminals. Damage to components could result. Always
use jumper wires between connectors for circuit
checking. NEVER probe through Weather-Pack seals.
Use an appropriate connector test adapter kit which
contains an assortment of flexible connectors used to
probe terminals during diagnosis. Use an appropriate
fuse remover and test tool for removing a fuse and to
adapt the fuse holder to a meter for diagnosis.
Open circuits are often difficult to locate by sight because
oxidation or terminal misalignment are hidden by the
connectors. Merely wiggling a connector on a sensor, or
in the wiring harness, may temporarily correct the open
circuit. Intermittent problems may also be caused by
oxidized or loose connections.
Be certain of the type of connector/terminal before
making any connector or terminal repair. Weather-Pack
and Com-Pack III terminals look similar, but are serviced
differently.
Wire Harness Repair: Twisted
Shielded Cable
Removal Procedure
1. Remove the outer jacket.
2. Unwrap the aluminum/mylar tape. Do not remove the
mylar.
047

6E±221 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
3. Untwist the conductors.
4. Strip the insulation as necessary.
048
Installation Procedure
1. Splice the wires using splice clips and rosin core
solder.
2. Wrap each splice to insulate.
3. Wrap the splice with mylar and with the drain
(uninsulated) wire.
049
4. Tape over the whole bundle to secure.
050
Twisted Leads
Removal Procedure
1. Locate the damaged wire.
2. Remove the insulation as required.
051

6E±222
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Installation Procedure
1. Use splice clips and rosin core solder in order to splice
the two wires together.
052
2. Cover the splice with tape in order to insulate it from
the other wires.
053
3. Twist the wires as they were before starting this
procedure.
054
4. Tape the wires with electrical tape. Hold in place.
055

6E±223 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Weather-Pack Connector
Tools Required
5-8840-0388-0 Weather-Pack II Terminal Remover
Removal Procedure
A Weather-Pack connector can be identified by a rubber
seal at the rear of the connector. This engine room
connector protects against moisture and dirt, which could
from oxidation and deposits on the terminals. This
protection is important, because of the low voltage and
the low amperage found in the electronic systems.
1. Open the secondary lock hinge on the connector.
070
2. Use tool 5-8840-0388-0 or the equivalent to remove
the pin and the sleeve terminals. Push on
5-8840-0388-0 to release.
NOTE: Do the use an ordinary pick or the terminal may
be bent or deformed. Unlike standard blade terminals,
these terminals cannot be straightened after they have
been improperly bent.
071
3. Cut the wire immediately behind the cable seal.
072
Installation Procedure
Make certain the connectors are properly seated and all
of the sealing rings are in place when you reconnect the
leads. The secondary lock hinge provides a backup
locking feature for the connector. The secondary lock
hinge is used for added reliability. This flap should retain
the terminals even if the small terminal lock tangs are not
positioned properly.
Do not replace the Weather-Pack connections with
standard connections. Read the instructions provided
with the Weather-Pack connector and terminal packages.
1. Replace the terminal.
2. Slip the new seal onto the wire.
3. Strip 5 mm (0.2º) of insulation from the wire.
4. Crimp the terminal over the wire and the seal.
073

6E±224
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
5. Push the terminal and the connector to engage the
locking tangs.
070
6. Close the secondary locking hinge.
Com-Pack III
General Information
The Com-Pack III terminal looks similar to some
Weather-Pack terminals. This terminal is not sealed and
is used where resistance to the environment is not
required. Use the standard method when repairing a
terminal. Do not use the Weather-Pack terminal tool
5-8840-0388-0 or equivalent. These will damage the
terminals.
Metri-Pack
Tools Required
5-8840-0632-0 Terminal Remover
Removal Procedure
Some connectors use terminals called Metri-Pack Series
150. These may be used at the engine coolant
temperature (ECT) sensor.
1. Slide the seal (1) back on the wire.2. Insert the 5-8840-0632-0 tool or equivalent (3) in
order to release the terminal locking tang (2).
060
3. Push the wire and the terminal out through the
connector. If you reuse the terminal, reshape the
locking tang.
Installation Procedure
Metri-Pack terminals are also referred to as ªpull-to-seatº
terminals.
1. In order to install a terminal on a wire, the wire must be
inserted through the seal (2) and through the
connector (3).
2. The terminal (1) is then crimped onto the wire.
061
3. Then the terminal is pulled back into the connector to
seat it in place.

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±227 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS

QOS

Diagnostics
± Malfunction Indicator Lamp (Service Engine
Soon lamp)
± Data Link Connector (DLC)
± Data Output
ECM Service Precautions
The ECM is designed to withstand normal current draws
associated with vehicle operation. Avoid overloading any
circuit. When testing for opens and shorts, do not ground
or apply voltage to any of the ECM's circuits unless
instructed to do so. These circuits should only be tested
using digital voltmeter. The ECM should remain
connected to the ECM or to a recommended breakout
box.
Intake Throttle Position (ITP) Sensor
ITP sensor is a potentiometer type and installed to the
intake throttle valve body. A voltage of 5V is applied
constantly from ECM to ITP sensor thereby to determine
by change in voltage the opening of the intake throttle
valve during warming up.
Transmission Range Switch
IMPORTANT:The vehicle should not be driven with the
transmission range switch disconnected; idle quality will
be affected.
The four inputs from the transmission range switch
indicate to the ECM which position is selected by the
transmission selector lever.
For more information on the transmission on the
transmission range switch, refer to
Automatic
Transmission
.
Accelerator Position Sensor (AP)
AP sensor is a potentiometer type and installed to
accelerator pedal bracket. A voltage of 5V constantly
applied from ECM to the sensor thereby to determine the
accelerator pedaling angle by change in voltage. Further,
this sensor is provided with an accelerator switch, which
is set off only when the accelerator pedal is stepped on.
Aftermarket Electrical and Vacuum
Equipment
Aftermarket (add-on) electrical and vacuum equipment is
defined as any equipment which connects to the vehicle's
electrical or vacuum systems that is installed on a vehicle
after it leaves the factory. No allowances have been
made in the vehicle design for this type of equipment.
NOTE: No add-on vacuum equipment should be added
to this vehicle.
NOTE: A d d - o n e l e c t r i c a l equipment must only be
connected to the vehicle's electrical system at the battery
(power and ground).
Add-on electrical equipment, even when installed to
these guidelines, may still cause the powertrain system to
malfunction. This may also include equipment not
connected to the vehicle electrical system such asportable telephones and radios. Therefore, the first step
in diagnosing any powertrain problem is to eliminate all
aftermarket electrical equipment from the vehicle. After
this is done, if the problem still exists, it may be diagnosed
in the normal manner.
Electrostatic Discharge Damage
Electronic components used in the ECM are often
designed to carry very low voltage. Electronic
components are susceptible to damage caused by
electrostatic discharge. Less than 100 volts of static
electricity can cause damage to some electronic
components. By comparison, it takes as much as 4000
volts for a person to feel even the zap of a static
discharge.
TS23793
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 vehicle seat.

Charge by induction occurs when a person with well
insulated shoes stands near a highly charged object
and momentary touches ground. Charges of the
same polarity are drained off leaving the person
highly charged with the opposite polarity. Static
charges can cause damage, therefore it is important
to use care when handling and testing electronic
components.
NOTE: To p r e ve n t p ossible electrostatic discharge
damage, follow these guidelines:

Do not touch the ECM connector pins or soldered
components on the ECM circuit board.

Do not open the replacement part package until the
part is ready to be installed.

Before removing the part from the package, ground
the package to a known good ground on the vehicle.

If the part has been handled while sliding across the
seat, while sitting down from a standing position, or
while walking a distance, touch a known good ground
before installing the part.