Isuzu KB P190. Manual - part 493

 

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Isuzu KB P190. Manual - part 493

 

 

ENGINE CONTROL SYSTEM (4JK1/4JJ1)   6E-355

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. 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.

Important: To prevent possible 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.

• Charge by induction occurs when a person with

well insulated shoes stands near a highly charged
object and momentarily touches ground. Charges
of the same polarity are drained off leaving the
person highly charged with opposite polarity.

Malfunction Indicator Lamp (MIL) Operation

The MIL is located in the instrument panel cluster. The
MIL will display the following symbols when
commanded ON:

The MIL indicates that an emission related fault (Type
A or B) has occurred (Euro 4 specification) or engine
performance related fault has occurred (except Euro 4
specification) and vehicle service is required. The
following is a list of the modes of operation for the MIL:

• The MIL illuminates when the ignition switch is

turned ON, with the engine OFF. This is a bulb test
to ensure the MIL is able to illuminate.

• The MIL turns OFF after the engine is started if a

diagnostic fault is not present.

• The MIL remains illuminated after the engine is

started if the ECM detects a fault. A DTC is stored
any time the ECM illuminates the MIL due to an
emission related fault (Euro 4 specification), and
engine performance related fault has occurred
(except Euro 4 specification).

Service Vehicle Soon (SVS) Lamp Operation (Euro
4 Specification)

The service vehicle soon (SVS) lamp is located in the
instrument panel cluster. The SVS lamp will display the
following symbol when commanded ON:

The SVS lamp indicates that a non-emission related
fault (Type C) has occurred and vehicle service
required. The following is a list of the modes of
operation for the SVS lamp:

• The SVS lamp illuminates when the ignition switch

is turned ON, with the engine OFF. This is a bulb
test to ensure the SVS lamp is able to illuminate.

• The SVS lamp turns OFF after the engine is

started if a diagnostic fault is not present.

• The SVS lamp remains illuminated after the engine

is started if the ECM detects a fault. A DTC is
stored any time the ECM illuminates the SVS lamp
due to a non-emission related fault.

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6E-356   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Engine Control Component Description

Accelerator Pedal Position (APP) Sensor

Legend

1. 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

 

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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.

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6E-358   ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Engine Coolant Temperature (ECT) Sensor

Legend

1. 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.

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