Toyota 4RUNNER 2007 Electrical Wiring Diagram page 96

2. Control System
∗ SFI system
The SFI system monitors the engine condition through the signals input from each sensors to the engine control module.
The control signal is sent to the engine control module TERMINALS #10, #20, #30, #40, #50 and #60 to operate the
injector (Fuel injection). The SFI system controls the fuel injection by the engine control module in response to the driving
conditions.
∗ ESA system
The ESA system monitors the engine condition through the signals input from each sensors to the engine control module.
The best ignition timing is decided according to this data and the data memorized in the engine control module. The
control signal is output to TERMINALS IGT1, IGT2, IGT3, IGT4, IGT5 and IGT6, and these signals control the igniter to
provide the best ignition timing.
∗ 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
emission is low), and warms up the heated oxygen sensors to improve their detection performance. The engine control
module evaluates the signals from each sensors, and outputs current to TERMINAL HT1B or HT2B to control the heater.
∗ Air fuel ratio sensor heater control system
The air fuel ratio sensor heater control system turns the heater on when the intake air volume is low (Temp. of exhaust
emission is low), and warms up the air fuel ratio sensor to improve detection performance of the sensor.
The engine control module evaluates the signals from each sensor, current is output to TERMINALS HA1A and HA2A,
controlling the heater.
∗ Fuel pump control system
The engine control module supplies current to TERMINAL FPR, and controls the operation speed of the fuel pump with
the FUEL PUMP relay.
∗ ACIS
The 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.
∗ ETCS–i
The ETCS–i controls the engine output at its optimal level in accordance with the opening of the accelerator pedal, under
all driving conditions.
∗ Engine start control system
The engine control module allows power to be supplied from the TERMINAL STAR/NSW to the STA relay via park/neutral
position SW until complete combustion is confirmed by engine RPM after the detection of ignition SW ST signal by the
TERMINAL STSW.
With this arrangement, engine can be started without holding the ignition key in the ST position. At the same time, the
TERMINAL ACCR is controlled so that the engine control module turns off ACC CUT relay, shutting off power to the
accessories.
∗ VVT–i
Controls the intake camshaft to an optimal valve timing in accordance with the engine condition.
3. 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 on the malfunction indicator lamp.
4. Fail–Safe System
When a malfunction has occurred in any system, there is a possibility of causing engine trouble due to continued control
based on that system. In that case, the fail–safe system either controls the system using the data (Standard values)
recorded in the engine control module memory, or else stops the engine.
4RUNNER (EM03M0U)
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