2007 ISUZU KB P190 EGR

6E-280 Engine Control System (4JH1)
EGR Solenid Valve Replacement
Removal Procedure 1. Disconenct the negative battery cable.
2. Disconnect a EGR solenoid valve harness connector.
3. Disconnect two hoses from the EGR solenoid valve.
4. Loosen two bolts and remove the EGR solenoid valve from the bracket.







Installation Procedure
1. Tighten the purge solenoid by tow bolts.
2. Connect a connector to the EGR solenoid valve.
3. Connect two hoses to the EGR solenoid valve.
4. Connect the negative battery cable.

Engine Coolant Temperature (ECT) Sensor
Replacement
1. Removal Procedure
2. Disconnect the negative battery cable.
3. Drain enough engine coolant so that the coolant level will be below the ECT sensor.
4. Disconnect connector from the ECT sensor.
5. Loosen and remove the ECT sensor from the thermostat housing.

Notice: Cool down the engine before above procedures
are carried out.









Installation Procedure
1.
Apply sealer to threads of screw at the ECT
sensor.
2. Tighten the ECT sensor with specified tightening torque.
Tightening Torque • Bolt: 13 N.m (1.3 kgf.m)
3. Connect a ECT sensor connector to the ECT sensor.
4. Fill the engine coolant.
5. Connect the negative battery cable.

Notice: Verify no engine coolant leaking from the
sensor threads after replacement.

Mass Air Flow (MAF) / Intake Air
Temperature (IAT) Sensor Replacement
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect a MAF & IAT sensor connector from the MAF & IAT sensor assembly.
3. Loosen the clips and remove the MAF & IAT sensor assembly from the intake duct housing.



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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-281






Installation Procedure
1. Install the MAF & IAT sensor assembly into intake air duct.
2. Tighten the clips.
3. Connect a MAF & IAT sensor connector to the MAF & IAT sensor assembly.
4. Connect the negative battery cable.

Turbocharger Solenoid Valve Replacement
[High Altitude Spec]
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect a harness connector from the turbocharger solenoid valve.
3. Disconnect two hoses from the turbocharge
r
solenoid valve.
4. Loosen a nut and remove the turbocharger solenoid valve from the bracket.




RTW 66ESH004001
Legend
1. Vaccum Pressure Sensor
2. To Turbocharger
3. EGR Solenoid Valve
4. To Vacuum Regulating Valve
5. Turbocharger Solenoid Valve


Installation Procedure
1. Set the turbocharger solenoid valve on the bracke
t
and tighten a nut.
2. Connect a harness connector to the turbocharge
r
solenoid valve.
3. Connect two hoses to the turbocharger solenoid valve.
4. Connect the negative battery cable.

Vacuum Pressure Sensor Replacement
[High Altitude Spec]
Removal Procedure
1. Disconnect the negative battery cable.
2. Disconnect a harness connector from the vacuum pressure sensor.
3. Loosen a bolt and remove the vacuum pressure sensor from the bracket.





RTW 66ESH004001
Legend
1. Vaccum Pressure Sensor
2. To Turbocharger
3. EGR Solenoid Valve
4. To Vacuum Regulating Valve
5. Turbocharger Solenoid Valve



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ISUZU KB P190 2007

Engine Control System (4JH1) 6E-283
Description And Operation
Engine Control Module (ECM) Description



RTW 66ESH001201
The engine control module (ECM) is designed to
withstand normal current draws associated with vehicle
operation. Avoid overloading any circuit. W hen testing
for opens and shorts, do not ground or apply voltage to
any of the ECM circuits unless instructed to do so. In
some cases, these circuits should only be tested using
a digital multi meter (DMM). The ECM should remain
connected to the ECM harness.
The ECM is located on the floor panel. The ECM mainl
y
controls the following.
• The fuel system control
• The exhaust gas recirculation (EGR) system
control
• The preheating (glow) system control
• The A/C compressor control
• On-board diagnostics for engine control
The ECM constantly observes the information from
various sensor s. The ECM controls the systems that
affect vehicle performance. The ECM performs the
diagnostic function of the system. The ECM can
recognize operational problems, alert the driver through
the malfunction indicator lamp (MIL), and store
diagnostic trouble codes (DTCs). DTCs identify the
system faults to aid the technician in making repairs.





ECM Voltage Description
The ECM supplies a buffered voltage to various
switches and sensor s. The ECM can do this because
resistance in the ECM is so high in value that a test
lamp 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-megaohm input impedance DMM, to
ensure accurate voltage readings. The input and/o
r
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
ON.
Aftermarket Electrical and Vacuum Equipment
Aftermarket or 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 the vehicle leaves the factory. No
allowances have been made in the vehicle design fo
r
this type of equipment. No add-on vacuum equipment
should be added to this vehicle. Add-on electrical
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 as
portable telephones and audios. Therefore, the first
step in diagnosing any powertrain fault is to eliminate all
aftermarket electrical equipment from the vehicle. Afte
r
this is done, if the fault still exists, the fault 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 b
y
electrostatic discharge. By comparison, as much as
4,000 volts may be needed for a person to feel even the
zap of a static discharge. 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.


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6E-286 Engine Control System (4JH1)
Exhaust Gas Recirculation (EGR) Solenoid Valve



RTW 76ESH003601
The engine control module (ECM) controls the exhaust
gas recirculation (EGR) flow amount based on the
engine speed, engine coolant temperature, intake ai
r
temperature, barometric pressure and fuel injection
quantity. The ECM controls the EGR valve b
y
controlling the EGR solenoid valve. The mass air flo
w
(MAF) sensor monitors EGR gas flow amount. An
expected MAF amount should be detected while the
engine running.

Intake Air Temperature (IAT) Sensor



RTW 66ESH001701
The intake air temperature (IAT) sensor is fitted
between the air cleaner and turbocharger internal to the
mass air flow (MAF) sensor. The IAT sensor is a
variable resistor. The IAT sensor measures the
temperature of the air entering the engine. The engine
control module (ECM) supplies 5 volts to the IAT signal
circuit and a ground for the IAT low reference circuit.
W hen the IAT sensor is cold, the sensor resistance is
high. W hen the air temperature increases, the senso
r
resistance decreases. W ith high sensor resistance, the
ECM detects a high voltage on the IAT signal circuit.
W ith lower sensor resistance, the ECM detects a lowe
r
voltage on the IAT signal circuit.
Mass Air Flow (MAF) Sensor



RTW 66ESH001701
The mass air flow (MAF) sensor is an air flow meter that
measures the amount of air that enters the engine. It is
fitted between the air cleaner and turbocharger. A small
quantity of air that enters the engine indicates
deceleration or idle. A large quantity of air that enters
the engine indicates acceleration or a high load
condition. The MAF sensor assembly consists of a MAF
sensor element and an intake air temperature senso
r
that are both exposed to the air flow to be measured.
The MAF sensor element measures the partial air mass
through a measurement duct on the sensor housing.



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Engine Control System (4JH1) 6E-297
Exhaust Gas Recirculation (EGR) System Description





RTW 66ELF000101
Legend
1. EGR Cooler
2. Engine Coolant Outlet
3. Engine Coolant Inlet
4. EGR Valve


5. ECM
6. MAF & IAT Sensor
7. Intake Throttle Valve
The EGR system recirculates a part of exhaust gas
back into the intake manifold, which results in reducing
nitrogen oxide (NOx) emissions. The EGR control
system uses an electronic control system solenoid valve
and vacuum control EGR valve to ensure both
driveability and low emission. The engine control
module (ECM) controls the EGR flow amount based on
the engine speed, engine coolant temperature, intake
air temperature, barometric pressure and fuel injection
quantity. The ECM controls the EGR valve opening b
y
controlling the EGR solenoid valve drive duty. The mass
air flow (MAF) sensor monitors EGR gas flow amount.
An expected MAF amount should be detected while the
engine running.

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SECTION 6F
EXHAUST SYSTEM
TABLE OF CONTENTS
PAGE
Main Data and Specifications ........................................................................................... 6F - 2
General Description .......................................................................................................... 6 F - 3
Removal and Installation .................................................................................................. 6F - 4
Inspection and Repair ....................................................................................................... 6F - 6
General Description .......................................................................................................... 6 F -7
EGR System Diagram........................................................................................................ 6F 9
Inspection ..................................................................................................................... ..... 6F-11
EGR Cooler (4JA1TC/4JH1TC Euro-III model)................................................................. 6F-12
Turbocharger ................................................................................................................... .. 6F -15
Main Data and Specifications....................................................................................... 6F -15
General Description .......................................................................................................... 6 F -16
Inspection and Repair ....................................................................................................... 6F -17
Special Tools .................................................................................................................. ... 6F -19
IHI Service Network ........................................................................................................... 6F -20
EXH
AU ST SY STEM 6F – 1

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EXHAUST SYSTEM 6F – 7

GENERAL DESCRIPTION
This system controls the formation of NOx emission by recirculating the exhaust gas into the combustion chamber
through the intake manifold.

4JA1T(L):
The two EGR valves are controlled by two Vacuum Switching Valve (VSV) controlled by EGR controller according to
signals from various sensors.
The amount of EGR depends on the number of engine rotations and the opening of the accelerator.







RTW 46ELF001201



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6F – 8 EXHAUST SYSTEM
4JA1TC/4JH1TC
The EGR system engine is controlled by ECM. Refer to “Engine driveability and emissions” section for detail.








RTW 46ELF001101



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