OUTLINE OF TCCS
- System Descriptio
n
COMPONENTS AND FUNCTION
S
The sensors, Engine ECU, and actuators, which
are the basis of the engine control system, are
shown in the following table, along with their
relationship with the main functions of the
engine control system, EFI, ESA and ISC
.
®
REFERENCE
The signals used for each control may differ for
some engines
.
COMPONENTS
SIG-
FUNCTIONS
EFI
ESA
IS
C
NAL
S
Manifold pressure senso
r
(
vacuum sensor)
(
D-type
PIM
Senses intake manifold pressure
.
EFI
)
Air flow meter
VS, KS
Senses intake air volume
.
(L-type EFI)
or
V
G
G
Senses crankshaft angle
.
Distributor
NE
Senses engine speed
.
Water temp
. sensor
THW
Senses coolant
temperature
.
Intake air temp
. sensor
THA
Senses intake air temperature
.
Throttle position
sensor
IDL
Senses when throttle valve is fully closed
.
(
on-off type)
PSW
Senses when throttle valve near fully open
.
Throttle position sensor
IDL
Senses when throttle valve is fully closed
.
Sensors
(
linear type)
VTA
Senses throttle valve opening angle
.
Ignition switch
STA
Senses when ignition switch is start position
.
Vehicle speed sensor
SPD
Senses vehicle speed
.
Oxygen sensor
OX
Senses oxygen density in exhaust gas
.
(02
sensor)
It is used to change the air-fuel ratio of the idl
e
Variable resistor
VAF
mixture
.
Senses whether transmission is in "P" or "N"
,
Neutral start switch
NSW
or in some other gear
.
Taillight & defogger relays
ELS
Senses electrical load
.
Air conditioner
A/C
Senses whether air conditioner is on or off
.
Knock sensor
KNK
Senses engine knocking
.
Determines injection duration and timing, igni
-
tion timing, idle speed, etc
., based upon dat
a
Engine ECU
from sensors and data stored in memory, an
d
sends appropriate signals to control actuators
.
No
.10
Injects fuel into intake manifold in accordanc
e
Injectors
No
.20
with signals from Engine ECU
.
When IGT signals from Engine ECU go off
,
IGT
primary
current to igniter is interrupted, an
d
Actuators
Igniter
IGF
sparks are generated by spark plugs
. Ignite
r
then sends IGF signals to Engine ECU
.
Controls idle speed by changing volume of ai
r
Idle speed control valve
ISC
flowing through throttle valve bypass in accor
-
dance with signals from Engine ECU
.
11
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