Control/Diagnosis/Fail-Safe System - Toyota 2001 CELICA Wiring Diagram

2. CONTROL SYSTEM
∗ SFI system
The SFI system monitors the engine condition through the signals input from each sensor (Input signals from (1) to (12)
etc.) to the engine control module. The best fuel injection timing is decided based on this data and the program
memorized by the engine control module, and the control signal is output to TERMINALS #10, #20, #30 and #40 of the
engine control module to operate the injector (Inject the fuel). The sequential multiport fuel injection (Electronic fuel
injection) system controls the fuel injection operation by the engine control module in response to the driving conditions.
∗ ESA system
The ESA system monitors the engine condition through the signals input to the engine control module from each sensor
(Input signals from (1), (2), (4) to (12) etc.). The best ignition timing is decided according to this data and the memorized
data in the engine control module, and the control signal is output to TERMINALS IGT1, IGT2, IGT3 and IGT4. This
signal controls the igniter to provide the best ignition timing for the driving conditions.
∗ Heated oxygen sensor heater control system
The heated oxygen sensor heater control system turns the heater on when the intake air volume is low (Temp. of
exhaust emissions is low), and warms up the heated oxygen sensors (Bank 1 sensor 1, bank 1 sensor 2) to improve
detection performance of the sensors.
The engine control module evaluates the signals from each sensor (Input signals from (1), (2), (4), (8) to (10) etc.), and
outputs current to TERMINALS HT1A, HT1B to control the heater.
∗ ACIS
ACIS includes a valve in the bulkhead separating the surge tank into two parts. This valve is opened and closed in
accordance with the driving conditions to control the intake manifold length in two stages for increased engine output in
all ranges from low to high speeds.
The engine control module judges the engine speed by the signals ( (4), (5) ) from each sensor and outputs signals to
the TERMINAL VSV to control the VSV (ACIS).
∗ MPX
The MPX communicates with the combination meter, as well as body ECU of the multiplex communication system
3. DIAGNOSIS SYSTEM
With the diagnosis system, when there is a malfunction in the engine control module signal system, the malfunctioning
system is recorded in the memory. The malfunctioning system can be found by reading the code displayed by the
malfunction indicator lamp.
4. FAIL−SAFE SYSTEM
When a malfunction has occurred in any system, if there is a possibility of engine trouble being caused by continued control
based on the signals from that system, the fail−safe system either controls the system by using data (Standard values)
recorded in the engine control module memory or else stops the engine.
2001 CELICA (EWD432U)
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