Actron Code Scanner CP9025, User Manual

Page: 83 / 88

83
ESA
See Electronic Spark Advance.
EVAP
See Evaporative Emission
system.
EVAP Vapor
Canister (EVAP-VC)
See Canister.
Evaporative
Emission System
(EVAP)
The EVAP system reduces the
amount of fuel vapors entering
the atmosphere. These vapors
are stored in a charcoal
canister. During warm engine
cruise conditions the stored
vapors are drawn into the
engine and burned.
EVAP-VC
See Canister.
Exhaust Gas
Recirculation (EGR)
The EGR system recirculates
exhaust gases back into the
intake manifold to reduce NO
x
emissions. Various types of
systems are in use on different
vehicles. Usually the ECU
directly controls EGR flow, but
on some vehicles it may just
activate a system controlled by
non-electronic means. Vacuum
controlled EGR valves are
normally closed. Applying
vacuum opens the valve.
Exhaust Gas
Sensor
See Oxygen sensor.
Exhaust Gas
Temperature
Sensor (EGTS)
Measures the temperature of
exhaust gases passing through
the EGR valve.
Fan Switch
Controls radiator cooling fan.
Fast Idle Control
Device (FICD)
The Fast Idle Control Device
controls idle speed while air
conditioning is activated and
when engine is running.
Feedback
Carburetor
This is used on early versions
of computer controlled engines.
It is a carburetor which can
have its air/fuel delivery
modified by an electronic signal
from the ECU.
FICD
See Fast Idle Control Device.
Frequency
The frequency of an electronic
signal is a measure of how
often the signal repeats a
voltage pattern in a one second
time span. For example:
suppose a signal starts at zero
volts, goes to five volts then
returns to zero again. If this
pattern repeats itself 100 times
in one second, then the signal
frequency is 100 cycles per
second - or 100 Hertz.
Fuel Cut Solenoid
Interrupts fuel delivery during
deceleration if the throttle is
closed and RPM is above some
minimum value. Used to
increase fuel economy and
reduce emissions.
Fuel Injector
An electronically controlled flow
valve. Fuel injectors are
connected to a pressurized fuel
supply. (The pressure is
created by a fuel pump.) No
flow occurs when the injector is
off (not energized). When the
injector is powered, it opens
fully allowing the fuel to flow.
The ECU controls fuel delivery
by varying the amount of time
the injectors are turned on.
Fuel Injector
Relay
Supplies power to the fuel
injectors.
Fuel Injector
resistors
Limits the electrical current to
the fuel Injector(s).
Fuel Rail
The pipe assembly that
supplies fuel to the injectors
and offers mechanical support.
Fuel Temperature
Sensor
Measures the temperature of
fuel in the fuel rail.
Ground
The return path for current to
flow back to its source. (Usually
the negative battery terminal.) It
is also the reference point from
which voltage measurements
are made. That is, it is the
connection place for the minus
(-) test lead from the voltmeter.
HAC
See High Altitude
Compensator.
Hard Failures
Hard failures cause the Check
Engine light (if equipped) to
come on or flash. The Check
Engine light (if equipped) will
not stay off until the problem
has been corrected.
HC
See Hydrocarbons.
Hertz (Hz)
A term for frequency - cycles
per second.
HIgh Altitude
Compensator
(HAC)
Adjusts the Air/Fuel mixture for
changes in altitude.
Hydrocarbons
(HC)
Polluting byproducts of fuel
combustion.
IACV
See Intake Air Control Valve.
I.C. Ignition Unit
Solid state ignition control unit.
Idle Control
System
This system maintains correct
idle speed when the engine
experiences mechanical or
electrical load changes.
Idle Mixture
Adjuster (IMA)
Maintains proper Air/Fuel ratio
while at idle.