Actron CP9135 OBD II AutoScanner User Manual
Page 27
Glossary
A-3
throttle
position,
coolant
temperature,
engine
load,
vehicle
speed,
Park/Neutral
switch
position,
and
knock
sensorcondition.
EVAP:
Evaporative
Emissions
System.
Hall
Effect
Sensor:
Any
of
a
type
of sensor utilizing
a
permanent
magnet
and
a
transistorized
Hall
Effect
switch.
Hall
Effect
type
sensors
may
be
used
to
measure
speed
and
position
of
the
crankshaft
or
camshaft
—
for
spark
timing
and
fuel
injector
control.
HO2S:
Heated
Oxygen
Sensor.
See
O2S.
IAC:
Idle
Air
Control.
A
device
mounted
on
the
throttle
body
which
adjusts
the
amount
of
air
bypassing
a
closed
throttle
so
that
the
PCM
can
control
idle
speed.
ICM:
Ignition
Control
Module.
I/M:
Inspection
and
Maintenance.
ISC:
Idle
Speed
Control.
A
small
electric
motor
mounted
on
the
throttle
body
and
controlled
by
the
PCM.
The
PCM
can
control
idle
speed
by
commanding
the
ISC
to
adjust
its
position.
Knock:
Uncontrolled
ignition
of
the
air/fuel
mixture
in
the
cylinder.
Also
referred
to
as
detonation
or
ping.
Knock
indicates
extreme
cylinder
pressures
or
“hotspots”
which
are
causing
the
air/fuel
mixture
to
detonate
prematurely.
Knock Sensor (KS):
Used
to
detect
engine
detonation
or
“knock.”
The
sensor contains
a
piezoelectric
element
and
is
threaded
into
the
engine
block.
Special
construction
makes
the
element
sensitive
only
to
engine
vibrations
associated
with
detonation.
KOEO:
Key
On,
Engine
Off.
KOER:
Key
On,
Engine
Running.
LCD:
Liquid
Crystal
Display.
LT:
Long
Term
fuel
trim.
M/T:
Manual
transmission
or
manual
transaxle.
MAF:
Mass
Air
Flow
Sensor.
Measures
the
amount
and
density
of
air
entering
the
engine
and
sends
a
frequency
or
voltage
signal
to
the
PCM.
The
PCM
uses
this
signal
in
its
fuel
delivery
calculations.
MAP:
Manifold
Absolute
Pressure
Sensor.
Measures
intake
manifold
vacuum
or
pressure
and
sends
a
frequency
or
voltage
signal
(depending
on sensor
type)
to
the
PCM.
This
gives
the
PCM
information
on
engine
load
for
control
of
fuel
delivery,
spark
advance,
and
EGR
flow.
MAT:
Manifold
Air
Temperature
sensor .
A
resistance
sensor in
the
intake
manifold
that
sends
a
voltage
signal
to
the
PCM
indicating
the
temperature
of
the
incoming
air.
The
PCM
uses
this
signal
for
fuel
delivery
calculations.
MIL:
Malfunction
Indicator
Lamp.
The
MIL
is
most
commonly
known
as
the
Check
Engine
Light.
Also
labeled
Service
Engine
Soon,
Power
Loss
or
Power
Limited.
Monitor:
A
test
performed
by
the
on-board
computer
to
verify
proper
operation
of
emission
related
systems
or
components.
MPFI
or
MFI:
Multi-Port
Fuel
Injection.
MPFI
is
a
fuel
injection
system
using
one
(or
more)
injector(s)
for
each
cylinder.
The
injectors
are
mounted
in
the
intake
manifold,
and
fired
in
groups
rather
than
individually.