Scan Tool Data Definitions - Isuzu N 2008 Series Workshop Manual

1A-40 Engine Control System (4JJ1)

Scan Tool Data Definitions

This information will assist in emission or driveability
problems. The displays can be viewed while the vehicle
is being driven. Always perform the Diagnostic System
Check - Engine Controls first. The Diagnostic System
Check will confirm proper system operation.
Engine Speed
This parameter displays the rotational speed of the
crankshaft as calculated by the ECM based on inputs
from the crankshaft position (CKP) sensor or camshaft
position (CMP) sensor.
Desired Idle Speed
This parameter displays the idle speed requested by
the ECM. The ECM will change desired idle speed
based on engine coolant temperature and other inputs.
Calculated Engine Load
This parameter displays the engine load in percent
based on inputs to the ECM from various engine
sensors. The scan tool will display a lower percentage
when the engine is at idle with little or no load. The
scan tool will display a higher percentage when the
engine is running at high engine speed under a heavy
load.
Coolant Temperature
This parameter displays the temperature of the engine
coolant as calculated by the ECM using the signal from
the engine coolant temperature (ECT) sensor. The
scan tool will display a low temperature when the ECT
sensor signal voltage is high, and a high temperature
when the ECT sensor signal voltage is low.
Engine Coolant Temperature Sensor
This parameter displays the voltage signal sent to the
ECM from the engine coolant temperature (ECT)
sensor. ECT sensor is a range of value indicating a low
voltage when the temperature is high, and a high
voltage when the temperature is low.
Intake Air Temperature
This parameter displays the temperature of the intake
air as calculated by the ECM using the signal from the
intake air temperature (IAT) sensor. The scan tool will
display a low temperature when the IAT sensor signal
voltage is high, and a high temperature when the IAT
sensor signal voltage is low.
Intake Air Temperature Sensor
This parameter displays the voltage signal sent to the
ECM from the intake air temperature (IAT) sensor. IAT
sensor is a range of value indicating a low voltage
when the temperature is high, and a high voltage when
the temperature is low.
Fuel Temperature
This parameter displays the temperature of the fuel as
calculated by the ECM using the signal from the fuel
temperature (FT) sensor. The scan tool will display a
low temperature when the FT sensor signal voltage is
high, and a high temperature when the FT sensor
signal voltage is low.
Fuel Temperature Sensor
This parameter displays the voltage signal sent to the
ECM from the fuel temperature (FT) sensor. FT sensor
is a range of value indicating a low voltage when the
temperature is high, and a high voltage when the
temperature is low.
MAF (Mass Air Flow)
This parameter displays the air flow into the engine as
calculated by the ECM based on the mass air flow
(MAF) sensor input. The scan tool will display a high
value at higher engine speeds, and a low value at lower
engine speed.
MAF Sensor (Mass Air Flow)
This parameter displays the voltage signal sent to the
ECM from the mass air flow (MAF) sensor. MAF sensor
is a range of value indicating a low voltage at lower
engine speed, and a high voltage at a higher engine
speeds.
Barometric Pressure
This parameter displays the barometric pressure
(BARO) as calculated by the ECM using the signal from
the BARO sensor. The scan tool will display a low
barometric pressure in high altitude area.
Barometric Pressure Sensor
This parameter displays the voltage signal sent to the
ECM from the barometric pressure (BARO) sensor.
BARO sensor is a range of value indicating a low
voltage in high altitude area, and a middle voltage in
sea level.
Desired Turbocharger Position
This parameter displays turbocharger nozzle position
desired by the ECM based on current boost pressure.
Desired Boost Pressure
This parameter displays boost pressure desired by the
ECM based on current driving conditions. This can be
compared to the actual boost pressure to determine
sensor accuracy or turbocharger control problems.
Boost Pressure
This parameter displays the boost pressure in the
intake duct as calculated by the ECM using the signal
from the boost pressure sensor. The scan tool will
display a low boost pressure when the low engine load,
and a high boost pressure when the high engine load.
Note that the true boost pressure is determined by
subtracting barometric pressure from the actual
reading.
Boost Pressure Sensor
This parameter displays the voltage signal sent to the
ECM from the boost pressure sensor. Boost pressure
sensor is a range of value indicating a low voltage
when the boost pressure is low (idle or lower engine
load) and a high voltage when the boost pressure is
high (higher engine load).