Isuzu 4HL1 Workshop Manual page 80

1A-78 Engine Control System
Tech 2 Data
Item
Display
16/63 Actual Rail
Pressure
17/63 Common Rail
Pressure Sensor
18/63 SCV Duty Ratio
19/63 SCV Current
20/63 EGR Duty Cycle
21/63 EGR Position
Sensor
22/63 EGR Target Lift
Position
Units
displayed
MPa This parameter refers to the
value calculated by the ECM
using the signals from the
common rail pressure sensor.
V This parameter refers to the
signal voltage input to the ECM
from the common rail pressure
sensor.
% This parameter refers to the
value calculated by the ECM
using desired fuel injection
quantity, desired common rail
pressure, engine speed. (Larger
duty cycle provides small SCV
position.)
mA This parameter refers to the
value calculated by the ECM
based on the pump discharge
determined from engine speed,
common rail pressure. (Larger
current provides smaller SCV
position.)
% This parameter refers to the DC
motor drive duty calculated from
desired fuel injection quantity,
engine speed, engine coolant
temperature, barometric
pressure, accelerator position,
and intake throttle position.
V This parameter refers to the
voltage signal input to the ECM
from the EGR valve position
sensor. (Larger EGR valve
position provides higher voltage.)
mm This parameter refers to the
value calculated by the ECM
using desired fuel injection
quantity, engine speed, and
engine coolant temperature.
Description How to use parameters
This parameter should be used
by comparing to the desired
common rail pressure. Using the
display needs those conditions:
the engine is completely warmed
up, all the accessory systems,
including air conditioner, are
turned off, and the idle speed is
stabilized. When the display
substantially deviates from the
desired value, fuel system
components (such as common
rail, pump, and fuel pipe),
common rail pressure sensor,
circuit, or ECM may be faulty.
When the signal from the sensor
deviates from the specified level,
the sensor, circuit, or ECM may
be faulty.
When the display is improper,
fuel system components (such as
common rail, pump, and fuel
pipe), common rail pressure
sensor, circuit, or ECM may be
faulty.
When the display is improper,
fuel system components (such as
common rail, pump, and fuel
pipe), common rail pressure
sensor, circuit, or ECM may be
faulty.
When the display deviates from
the specified level, EGR valve
sensors, circuit, or ECM may be
faulty.
When the display deviates from
the specified level as the EGR
valve is operated, the sensor,
circuit, EGR valve, or ECM may
be faulty.
When the display deviates from
the specified level, EGR valve
sensors, circuit, or ECM may be
faulty.