2007 ISUZU KB P190 sensor

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-343
Excessive Smoke (Black Smoke)
ChecksAction
Definition:
Black smoke under load, idle or start up hot or cold.
Preliminary Check • Ensure the vehicle has an actual problem.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Remove the air cleaner and check for dirt, or for air ducts being plugged or restricted. Replace as necessary.
• Inspect the fuel quality (cetane index).
• Inspect the engine oil level and quality.
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the MAF parameter for a skewed or slow MAF sensor.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ±5 MPa ( ±725 psi) quick enough.
• Observe the Barometric Pressure (BARO) parameter. The BARO parameter should indicate near surrounding barometric pressure. Refer to Altitude vs. Barometric
Pressure. (Standard output)
• Observe the Boost Pressure and BARO with ignition ON and engine OFF. Both parameters should be within the 7.0 kPa (1.0 psi) each other. (High output)
Fuel System Checks Inspect the fuel system for the following conditions. Refer to the Fuel System section.
• Fuel injectors. Remove the injectors and visually inspect.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Pilot Injection Control with a scan tool.
• Observe the Fuel Compensation for each cylinder at idle on the scan tool.
Air Intake System Checks Inspect the air intake system for the following conditions.
• Air cleaner, air intake ducts and charge air cooler for a restriction, holes, or leaks.
• A restriction in the turbocharger inlet duct.
• Intake throttle valve for a stuck condition.
• A restriction or leak in the intake manifold.
• A restriction or damaged at MAF sensor.
• A worn or damaged turbocharger turbine wheel, shaft or compressor wheel. Refer to turbocharger inspection in the Engine Mechanical section.
Exhaust System Checks Inspect the exhaust system for a possible restriction. Refer to the Exhaust System
section.

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-345
Excessive Smoke (White Smoke)
ChecksAction
Difinition:
White smoke under load, idle or start up hot or cold.
Preliminary Check • Ensure the vehicle has an actual problem.
• Inspect the ECM grounds for being clean, tight, and in their proper locations.
• Inspect the fuel quality (cetane index).
• Inspect the programmed fuel injector ID code for each cylinder.
• Inspect the Scan Tool Data List in this section.
• Inspect the Service Bulletin.
Sensor Checks Inspect the engine control sensors for the following conditions. Refer to the Scan Tool
Data List in this section.
• Compare the Coolant Temperature with the Intake Air Temperature (IAT) and Fuel Temperature (FT) parameters on a cold engine condition. If the difference among
temperature reading is more than 5 °C (9 °F) on a cold engine, check for high
resistance in each circuit or for a skewed sensor.
Notice: The mass air flow (MAF) sensor is heated and as a result the IAT may indicate
a higher than normal intake air temperature if the ignition switch is being ON.
• Observe the Fuel Rail Pressure (FRP) Sensor parameter with the engine OFF. The FRP Sensor should read 0.9 to 1.0 volt with the key ON and engine OFF after the
engine has stopped running for a minimum of 1 minute. If not, check for high
resistance in each circuit or for a skewed sensor.
• Observe the Fuel Rail Pressure and Desired Fuel Rail Pressure parameter between idle and W.O.T. (accelerator pedal full travel) in Neutral. Fuel Rail Pressure
parameter should follow within ± 5 MPa ( ± 725 psi) quick enough.
• Observe the Accelerator Pedal Position (APP). APP parameter should change linearly from 0 to 100% according to the accelerator pedal operation.
• Observe the Boost Pressure and Barometric Pressure (BARO) with ignition ON and engine OFF. Both parameters should be within the 7.0 kPa (1.0 psi) each other.
• Crankshaft position (CKP) sensor is tight and the sensor rotor is not damaged.
Fuel System Checks • If excessive smoke is present, check for a stuck open fuel injector. Inspect for fuel
leakage into the combustion chamber.
• Fuel injectors. Remove the injectors and visually inspect.
• Perform the Cylinder Balance Test with a scan tool.
• Perform the Pilot Injection Control with a scan tool.
• Observe the Fuel Compensation for each cylinder at idle on the scan tool.
Air Intake System Checks Inspect the air intake system for the following conditions.
• Air cleaner, air intake ducts and charge air cooler for a restriction, holes, or leaks.
• A restriction in the turbocharger inlet duct.
• Intake throttle valve for a stuck condition.
• A restriction or leak in the intake manifold.
• A restriction or damaged at MAF sensor.
• Perform the Swirl Control Solenoid Test with a scan tool. Inspect the diaphragm valve operation when it commanded ON/ OFF.
• A worn or damaged turbocharger turbine wheel, shaft or compressor wheel. Oil leak from turbocharger. Refer to turbocharger inspection in the Engine Mechanical
section.

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-353
Description and Operation
Engine Control Module (ECM) Description
Engine Control Module (ECM) Service Precautions
Important:The symbol ! warns you of an electric shock
hazard. To avoid shock and possible serious injury, DO NOT
touch the terminals. When disconnecting the harness
connectors, always turn OFF the ignition switch or disconnect
the battery cable.
The engine control module (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 circuits unless instructed to do so. In
some cases, these circuits should only be tested using
a DMM. The ECM should remain connected to the
ECM harness.
The ECM is located inside of engine compartment via
mounting bracket and is behind air cleaner case. The
ECM mainly controls the following. • The fuel system control
• The exhaust gas recirculation (EGR) system control
• The preheating (glow) system control
• The A/C compressor control
• The immobilizer control
• On-board diagnostics for engine control
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. 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.
RTW56ESH000201
RTW56ESH004401

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ISUZU KB P190 2007

6E-354 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
ECM Input & Output
ECM Voltage Description
The ECM supplies a buffered voltage to various
switches and sensors. 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/ or
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 for 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. After this is done, if the
fault still exists, the fault may be diagnosed in the
normal manner.
RTW76EMF000501
Sensor inputs
· Intake air temperature (IAT) sensor
· Mass air flow (MAF) sensor
· Engine coolant temperature (ECT) sensor
· Fuel temperature (FT) sensor
· Barometric pressure (BARO) sensor
· Boost pressure sensor (High output engine)
· Accelerator pedal position (APP) sensor
· EGR position sensor
· Intake throttle position sensor
· Crankshaft position (CKP) sensor
· Camshaft position (CMP) sensor
· Fuel rail pressure (FRP) sensor
· Vehicle speed sensor (VSS)
Switch input
· Ignition switch (ON/start position)
· Clutch switch (M/T)
· Brake switch
· Neutral switch
· Cruise main switch
· Cruise cancel switch
· Cruise resume/ accel. switch
· Cruise set/ cast switch
· Fuel filter switch
· A/C switch
· Diagnostic request switch
Fuel injection control
· Fuel rail pressure (FRP) regulator
· Fuel injector #1
· Fuel injector #2
· Fuel injector #3
· Fuel injector #4
Relay control outputs
· Glow relay
· Fuel pump relay
· Starter cut relay
· A/C compressor relay
Lamp control
· Malfunction indicator lamp (MIL)
· Service vehicle soon (SVS) lamp
· Glow indicator lamp
· Fuel filter lamp
Communication
· Controller area network (CAN)
Actuator control
· Intake throttle solenoid
· EGR solenoid
· Swirl control solenoid
· Turbocharger nozzle control solenoid
(High output engine)ECM

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ISUZU KB P190 2007

6E-356 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Engine Control Component Description
Accelerator Pedal Position (APP) Sensor
Legend1. Accelerator pedal position (APP) sensor
2. Accelerator pedal bracket
3. Nut

The APP sensor is mounted on the accelerator pedal
control assembly. The sensor is made up of three
individual sensors within one housing. The ECM uses
the APP sensors to determine the amount of
acceleration or deceleration that is desired. The APP
sensors are potentiometer type sensors. Each APP
sensor provides a different signal to the ECM on the
each signal circuit, which relative to the position
changes of the accelerator pedal angle. The APP
sensor 1 signal voltage is low at rest and increases as
the pedal is depressed. The APP sensor 2 and APP
sensor 3 signal voltage is high at rest and decreases as
the pedal is depressed. Barometric Pressure (BARO) Sensor
The BARO sensor is located on the intake manifold.
The BARO sensor is a transducer that varies voltage
according to changes the barometric pressure. The
BARO sensor provides a signal to the ECM on the
signal circuit, which is relative to the pressure changes
of the barometric pressure. The ECM should detect a
low signal voltage at a low barometric pressure, such
as high altitude place. The ECM should detect high
signal voltage at a high barometric pressure. The ECM
uses this voltage signal to calibrate the fuel injection
quantity and injection timing for altitude compensation.
Boost Pressure Sensor
Legend 1. Boost pressure sensor

RTW56ESH000301
1
2
3
RTW76ESH002401
RTW76ESH003801
1

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-357
The boost pressure sensor is located in the air
induction tubing. The boost pressure sensor is a
transducer that varies voltage according to changes in
the air pressure inside the air tubing. The boost
pressure sensor provides a signal to the ECM on the
signal circuit, which is relative to the pressure changes
in the air tubing. The ECM should detect a low signal
voltage at a low boost pressure, such as low engine
load. The ECM should detect high signal voltage at a
high boost pressure, such as high engine load.
Camshaft Position (CMP) Sensor
Legend 1. Timing chair sprocket
2. Camshaft position (CMP) sensor
3. Rotating direction

The CMP sensor is installed on the timing chain
sprocket cover at the front of the camshaft idle gear.
The CMP sensor detects total of five projections per
one engine cycle (four projections arranged equally
every 90 ° and one reference projection on the timing
chain sprocket surface). The CMP sensor is a magnetic
resistance element (MRE) type sensor, which
generates a square wave signal pulse. Crankshaft Position (CKP) Sensor
Legend
1. Crankshaft position (CKP) sensor

Legend
1. Crankshaft position (CKP) sensor
2. Sensor rotor
3. Rotating direction

The CKP sensor is located on the left-hand of the
cylinder block rear and it is behind the starter motor.
The sensor rotor is fixed on the crankshaft. There are
56 notches spaced 6 ° apart and a 30 ° section that is
open span. This open span portion allows for the
detection of top dead center (TDC). The CKP sensor is
a magnetic resistance element (MRE) type sensor,
which generates a square wave signal pulse.
Detecting the open span portion from the CKP sensor
and one reference projection from the camshaft
position (CMP) sensor, the ECM determines cylinder
#1 compression TDC to ensure they correlate with
each other.
RTW56ESH000401
1
3 2
15
RTW76ESH002301
1
RTW76ESH003301
A
A Section A-A
1
2 3

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ISUZU KB P190 2007

6E-358 ENGINE CONTROL SYSTEM (4JK1/4JJ1)
Engine Coolant Temperature (ECT) Sensor
Legend1. Engine coolant temperature (ECT) sensor

The ECT sensor is installed to the thermostat housing.
The ECT sensor is a variable resistor and it measures
the temperature of the engine coolant. When the ECT
sensor is cold, the sensor resistance is high. When the
engine coolant temperature increases, the sensor
resistance decreases. With high sensor resistance, the
ECM detects a high voltage on the signal circuit. With
lower sensor resistance, the ECM detects a lower
voltage on the signal circuit.
Fuel Temperature (FT) Sensor
Legend 1. Fuel temperature (FT) sensor
2. Fuel rail pressure (FRP) regulator

The FT sensor is installed to the fuel supply pump. The
FT sensor is a variable resistor and it measures the
temperature of the fuel entering the fuel supply pump.
When the FT sensor is cold, the sensor resistance is
high. When the fuel temperature increases, the sensor
resistance decreases. With high sensor resistance, the
ECM detects a high voltage on the signal circuit. With
lower sensor resistance, the ECM detects a lower
voltage on the signal circuit.
Intake Air Temperature (IAT) Sensor
The IAT sensor is fitted between the air cleaner and
turbocharger. It is internal to the mass air flow (MAF)
sensor. The IAT sensor is a variable resistor and it
measures the temperature of the air entering the
engine. When the IAT sensor is cold, the sensor
resistance is high. When the air temperature increases,
the sensor resistance decreases. With high sensor
resistance, the ECM detects a high voltage on the
signal circuit. With lower sensor resistance, the ECM
detects a lower voltage on the signal circuit.
RTW56ESH000701
1
RTW56ESH006101
12
AAW46ESH001401

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ISUZU KB P190 2007

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-359
Mass Air Flow (MAF) SensorThe 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
speed. 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 (IAT) sensor 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.
Fuel System Description
The common rail system uses a type of accumulator
chamber called the fuel rail to store pressurized fuel,
and injectors that contain electronically controlled
solenoid valves to spray the pressurized fuel in the
combustion chambers. The injection system (injection
pressure, injection rate, and injection timing) is
controlled by the ECM, and therefore the common rail
system can be controlled independently, free from the influence of engine speed and load. This ensures a
stable injection pressure at all time, particularly in the
low engine speed range, so that black smoke specific
to diesel engines generated during vehicle starting or
acceleration can be reduced dramatically. As a result,
exhaust gas emissions are clear and reduced, and
higher output is achieved.
AAW46ESH001401
RTW76EMF000401
Supply pump
One-way valve
Fuel tank Fuel filter
Camshaft
position
sensor Crankshaft
position
sensor Various sensors
(accelerator position sensor, coolant temperature,
mass air flow, etc.) Injectors
Pressure sensor
Fuel rail Pressure
limiter valve
ECM

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