Instruction manual

79
Glossary
AAC
See Auxiliary Air Control valve.
A/C
Air Conditioning.
A/C Amplifier
The A/C Amplifier sends a
signal to the ECU representing
the temperature at the
Evaporator outlet. The ECU
then adjusts the engine cooling
fan operation as necessary.
A/C Switch
Air Conditioning switch. Switch
signals ECU when Air
Conditioning is activated. The
ECU will increase idle speed to
prevent engine stalling whenever
Air Conditioning is engaged.
Actuator
Devices which are powered by
the ECU to control mechanical
things. Actuator types include
relays, solenoids and electric
motors. Actuators allow the
ECU to control engine
operation.
A/F
Air to Fuel ratio. This refers to
the proportion of air and fuel
delivered to the cylinder for
combustion. For example, if you
have 14 times more air than
fuel (by weight) than the A/F
ratio is 14:1 (read as “fourteen
to one”). Note that a colon is
written instead of a slash.
AFM
See Air Flow Meter.
Air Cut Valve
The Air Cut Valve is mounted
on the Auxiliary Air Control
valve (AAC). It limits the
amount of air flowing through
the AAC based on coolant
temperature to reduce the
possibility of dieseling (engine
run-on with ignition key off).
Air Flow Meter
(AFM)
The part of the air intake system
containing the Air Flow sensor.
Air Flow Sensor
This sensor measures the
amount of air entering the
engine and sends a signal to
the ECU. Depending upon
sensor type, the signal may be
a voltage or frequency. The
signal voltage (or frequency)
increases when the amount of
incoming air goes up. The ECU
needs to know incoming air flow
to properly adjust air/fuel
mixture and ignition timing for
varying engine load and
operating conditions.
Air Induction
System
System including but not limited
to the Air Intake system, By-
Pass Control system, Intake
Control system and Throttle
Body.
Air Injection Valve
(AIV)
The AIV is a one way reed valve
with a lock-out diaphragm.
When negative exhaust
pressure is present, the AIV will
allow air to enter the exhaust
manifold allowing burning of HC
and CO in the catalytic
converter.
Air Intake System
This system contains
components like the air cleaner,
air intake pipe, throttle body,
fast idle mechanism, intake
manifold, Electronic air control
valve and bypass control
system.
Air Pump Injection
System
A system that reduces HC and
CO emissions by injecting air
into the exhaust manifold. The
extra air helps partially burned
exhaust gases to completely
burn and reduce pollution.
Air Regulator
The Air regulator allows some
air to bypass a closed throttle.
Used when the engine is cold
for fast idle.
Air Suction
System (AS)
The Air Suction system draws
air into the exhaust port to
reduce the HC and CO
emissions. The extra air helps
partially burned exhaust gases
to completely burn and reduce
pollution.
Air Temperature
Sensor (TA)
This sensor is a thermistor – a
resistor whose resistance
changes with temperature. The
hotter the sensor gets, the
lower the resistance becomes.
The sensor is located along the
path of air entering the engine.
The ECU uses air temperature
to provide the proper air/fuel
mixture for the desired engine
operating condition.
AIV
See Air Injection Valve.
AP
Air pump. Used in Air Pump
Injection System.
AS
See Air Suction System.
A/T
Automatic Transmission.
ATC
See Automatic Temperature
control.
ATCV
See Automatic Transmission /
Transaxle Control.
Atmospheric
Pressure Sensor
(PA)
This sensor is an electronic
module which sends a signal to
the ECU indicating atmospheric
pressure. Depending upon
sensor type, the signal may be
a dc voltage or a frequency.
More pressure makes the
sensor signal increase (higher
voltage or frequency). The ECU
needs to know air pressure to