Toyota 3S-GE Repair Manual page 181

ENGINE — EFI SYSTEM EG4 67
ELECTRONIC CONTROL SYSTEM
Knock Sensor i
\ 5 5 V7 777*' "ECU
ACISVSV
SW20 Knock Sensor
Ignition Main Relay * ACIS VSV Oxygen Sensor
Fuel Pressure A/C Idle-Up Valve
Control VSV
Circuit Opening Relay
A ;
0115*
\§ ;
{Q \f
' OXVgen Sensor
\ '
5
Water Temperature lntake Alf
Temperature Sensor
Sens" EFI Main Relay
Water Temperature A/CI|d|e_Up Vajve
Sensor
. Vacuum Sensor
lntake Air
Temperature Sensor
\ §
N1?» »
EFI Main Rela V; ""4. 3
\ { ECU
Circuit Opening 6/?' v
E: i ' . ? ; r s21ve
>
1'1 C02?
The control system consists of sensors which detect various engine conditions, and an ECU
which determines the injection volume (timing) based on the signals from the sensors.
The various sensors detect the intake air pressure, engine speed, oxygen density in the exhaust
gas, engine coolant temperature, intake air temperature and atmospheric pressure etc. and
convert the information into an electrical signal which is sent to the ECU. Based on these signals,
the ECU calculates the optimum ignition timing for the current conditions and operates the
injectors. The ECU not only controls the fuel injection timing, but also the self—diagnostic
function which records the occurrence of a malfunction, ignition timing control and idle speed
control.