Appendix a glossary, Glossary, Appendix a – Actron CP9135 OBD II AutoScanner User Manual
Page 25
Glossary
A-1
A/C:
Air
Conditioning.
A/F:
Air/Fuel
ratio.
The
proportion
of
air
and
fuel
delivered
to
the
cylinder
for
combustion.
For
example,
an
A/F
ratio
of
14:1
denotes
14
times
as
much
air
as
fuel
in
the
mixture.
A
typical
ideal
A/F
ratio
is
14.7:1.
AC
Clutch
Relay:
The
PCM
uses
this
relay
to
energize
the
A/C
clutch,
turning
the
A/C
system
on
or
off.
AC
Pressure
Sensor:
Measures
air
conditioning
refrigerant
pressure
and
sends
a
voltage
signal
to
the
PCM.
AC
Pressure
Switch:
A
mechanical
switch
connected
to
the
A/C
refrigerant
line.
The
switch
is
activated
(sending
a
signal
to
the
PCM)
when
the
A/C
refrigerant
pressure
becomes
too
low.
Actuator:
Actuators
such
as
relays,
solenoids,
and
motors
allow
the
PCM
to
control
the
operation
of
vehicle
systems.
Air
Injection
Reaction
(AIR)
System:
An
emission
control
system
operated
by
the
PCM.
During
cold
starts,
an
air
pump
injects
outside
air
into
the
exhaust
manifold
to
help
burn
hot
exhaust
gases.
This
reduces
pollution
and
speeds
warm-up
of
oxygen
sensors
and
catalytic
converters.
After
the
engine
is
warm,
the
air
will
either
be
“dumped”
back
to
the
atmosphere
(or
into
the
air
cleaner
assembly)
or
sent
to
the
catalytic
converter.
Bank
1:
The
standard
way
of
referring
to
the
bank
of
cylinders
containing
cylinder
#1.
In-line
engines
have
only
one
bank
of
cylinders.
Most
commonly
used
to
identify
the
location
of
oxygen
sensors.
See
O2S,
Sensor 1,
Sensor 2.
Bank
2:
The
standard
way
of
referring
to
the
bank
of
cylinders
opposite
cylinder
#1.
Found
on
V-6,
V-8,
V-10,
etc.
and
horizontally
opposed
engines.
Most
commonly
used
to
identify
the
location
of
oxygen
sensors.
See
O2S,
Sensor
1,
Sensor 2.
BARO:
Barometric
Pressure
Sensor.
See
MAP
Sensor.
Boost
Control
Solenoid:
A
solenoid
that
is
energized
by
the
PCM,
in
order
to
control
supercharger
boost
pressure.
Brake
Switch
Signal:
An
input
signal
to
the
PCM
indicating
that
the
brake
pedal
is
being
pressed.
This
signal
is
typically
used
to
disengage
Cruise
Control
systems
and
Torque
Converter
Clutch
(TCC)
solenoids.
See
also
TCC.
CAM:
Camshaft
Position
Sensor.
Sends
a
frequency
signal
to
the
PCM
in
order
to
synchronize
fuel
injector
and
spark
plug
firing.
CARB:
California
Air
Resources
Board.
Governing
body
for
emissions
control
in
California.
Appendix A
Glossary