Electronic Control System - Toyota 3S-GTE Repair Manual

EG-114
ENGINE — EFI SYSTEM
I531.-'I11
ELECTRONIC CONTROL SYSTEM
1
Oxygen Sensor f .
i A/C Idle-Up Valve
Vacuum Sensor
VSV for EGR
Intake Air Temperature Sensor
(tor Intake Manifold) Circuit Opening Relay
Knock Sensor
gs;
' ' _ ECU
O
Fuel Pump Relay
I
I Solenoid Resistor
Water Temperature Sensor
r'
Fuel Pump Resistor EFI Main Relay
l
Intake Air Temperature Sensor
(for Air Cleaner Case)
Y F'lB45Z
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, idle speed
control and EGR control.