Specifications

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.
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