1998 ISUZU TROOPER Intake sensor

6E±204
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Installation Procedure
1. Install the IAT sensor into the grommet in the intake
air duct.
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2. Correct the IAT electrical connector.
3. Connect the negative battery cable.
Manifold Absolute Pressure
(MAP) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect the EGR valve.
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3. Disconnect the MAP sensor connector from the MAP
sensor.
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4. Remove the bolts and the MAP sensor from the
intake manifold.
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6E±205 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Installation Procedure
1. Install the MAP sensor and bolts on the intake
manifold.
Torque: 4 N´m (35 lb in)
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2. Connect the MAP sensor connector.
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3. Connect the EGR valve.
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4. Connect the negative battery cable.
Oil Temperature (OT) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the battery.
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6E±208
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Installation Procedure
1. Install the ECM.
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2. Install the bolts, ECM bracket and battery bracket.
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3. Connect the ECM connector.
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4. Connect the negative battery cable.
If the ECM is replaced, the new ECM will need to be
programmed.
EEPROM
General Description
The Electronically Erasable Programmable Read Only
Memory (EEPROM) is a permanent memory that is
physically soldered within the ECM. The EEPROM
contains program and calibration information that the
ECM needs to control powertrain operation.
Functional Check
1. Perform the On-Board Diagnostic System Check.
2. Start the engine and run for one minute.
3. Scan for DTCs using the Tech 2.
Intake Throttle Position (ITP)
Sensor
Removal Procedure
1. Disconnect the negative battery cable.

6E±209 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
2. Remove the cover of the intercooler.
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3. Remove the bolts and the left side bracket to the
intercooler.
4. Remove the air duct with bracket from the intercooler.
5. Remove the throttle body from the intake manifold.
6. Disconnect the ITP sensor electrical connector and
throttle motor control connector.
7. Remove the bolts and the ITP sensor from the throttle
body.
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NOTE: Do not clean the ITP sensor by soaking it in
solvent. The sensor will be damaged as a result.
Function Check
Use a Tech 2 to check the ITP sensor output voltage at
closed throttle.

The voltage should be under 0.85 volt.

If the reading is greater than 0.85 volt, check the
throttle shaft to see if it is binding.
If the throttle shaft is not binding and the throttle cable
is properly adjusted, install a new ITP sensor.
Installation Procedure
1. Install the ITP sensor on the throttle body with the
bolts.
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2. Install the throttle body to the intake manifold and the
air duct with bracket between throttle body and
intercooler.
Torque: 20 N´m (14 Ib ft)
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3. Connect the ITP sensor electrical connector and
throttle motor control connector.
4. Install the bracket to the intercooler.
5. Install the cover of intercooler.
6. Install the negative battery cable.

6E±216
4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
2. Install the fuel return adapter.
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3. Install the rear side engine hanger. Tighten the rear
side engine hanger fixing bolts to specified torque.
Torque: 19 N´m (14 lb ft)
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4. Install the cylinder head. Refer to engine mechanical
section.
5. Install the intercooler assembly.
6. Connect the negative battery cable.
Rail Pressure (RP) Sensor
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the air cleaner cover and air duct.
3. Remove the intercooler assembly.
4. Remove the injector oil pipe.
5. Remove the intake throttle valve.
6. Remove the cylinder head cover noise inselation.
7. Remove the cylinder head cover.
8. Remove the RP sensor.
Installation Procedure

Refer to the RP Sensor Programming.
1. Install the RP sensor.
2. Install the cylinder head cover.
3. Install the cylinder head cover noise inselation.
4. Install the intake throttle valve.
5. Install the injector oil pipe.
6. Install the intercooler assembly and tighten
intercooler assembly fixing bolts to specified torque.
Torque: 20 N´m (14 lb ft)
7. Install the air cleaner cover and air duct.
8. Connect the negative battery cable.
Fuel Tank
Removal Procedure
Refer toEngine Fuel in 4JX1 Engine section.
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6E±217 4JX1±TC ENGINE DRIVEABILITY AND EMISSIONS
Throttle Body (TB)
Removal Procedure
1. Disconnect the negative battery cable.
2. Remove the cover of the intercooler.
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3. Remove the bolts and the left side bracket to the
intercooler.
4. Remove the air duct with bracket from the intercooler.
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5. Remove the throttle body assembly from the intake
manifold.
6. Disconnect the ITP sensor electrical connector.
Installation Procedure
NOTE: Do not use solvent of any type when you clean the
gasket surfaces on the intake manifold and the throttle
body assembly. The gasket surfaces and the throttle body
assembly may be damaged as a result.
If the throttle body gasket needs to be replaced,
remove any gasket material that may be stuck to the
mating surfaces of the manifold.

Do not leave any scratches in the aluminum casting.
1. Install the throttle body assembly to the intake
manifold and the air duct with bracket between
throttle body and intercooler.
Torque: 20 N´m (14 Ib ft)
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2. Connect the ITP sensor electrical connector and
throttle motor control connector.
3. Install the bracket to the intercooler.
4. Install the cover of intercooler.
5. Connect the negative battery cable.
Air Conditioning (A/C) Relay
Removal Procedure
1. Remove the fuse and relay box cover from under the
hood.
2. Consult the diagram on the cover to determine which
is the correct relay.
3. Pull the relay straight up and out of the fuse and relay
box.
Installation Procedure
1. Insert the relay into the correct place in the fuse and
relay box with the catch slot facing forward.
2. Press down until the catch engages.

An audible ªclickº will be heard.
3. Install the fuse and relay box cover.
Exhaust Gas Recirculation
(EGR) Vacuum Switch Valve
(VSV)
Removal Procedure
1. Disconnect the negative battery cable.

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