Page 100 of 241

CONTROL UNIT
MULTIPORT FUEL SYSTEM (MFI)13A-6
CONTROL UNITM2132021500153
ENGINE CONTROL MODULE (ECM)
ECM is installed in the engine room. ECM judges
(calculates) the optimum control to deal with the con
-
stant minute changes in driving conditions based on
information input from the sensors and drives the
actuator. ECM is composed of 32-bit microprocessor
and Random Access Memory (RAM), Read Only
Memory (ROM) and Input /Output interface. ECM uses flash-memory ROM that allows re-writing of
data so that change and correction of control data is
possible using special tools. It also uses Electrically
Erasable Programmable Read Only Memory
(EEPROM) so that studied compensation data is not
deleted even if battery terminals are disconnected.
ECM CONNECTOR INPUT/OUTPUT PIN ARRANGEMENT
NOTE: *: California
AK604119
ECM
Microprocessor
RAM Input
interfaceOutput
interface Input
sensorOutput
actuator
AB
ROM
AK602565AC
1 2 3 4 5 6 7 8 9 10 11 1213 14 15 16
17 18 19 20 21 91
90
89
87
86
84 85
83 82
88 92 93 94
95 96 97 98 99
109
108
107 106
105
104
103
102
112 113 114 115 116 117 118
100 101
111
110
41
40
39
38
37
36
35
34
33 32
31
30
29
28
27
26
25
24
23
2260
59
58
57
56
55
54
53
52
51
50
49 48
47
46
45
44
43
4263
61 62 6471 72 73 74 75 76 77 78 79 80 81
1Intake engine oil control valve2No.1 injector
3No.2 injector4Ignition coil No.1 (ignition power transistor)
5Ignition coil No.2 (ignition power transistor)6Starter active signal
7Exhaust camshaft position sensor8Crankshaft position sensor
9Sensor supplied voltage10Throttle position sensor (main)
11Throttle position sensor (sub)12Power supply voltage applied to throttle
position sensor
13Throttle position sensor ground14Intake camshaft position sensor
Page 111 of 241

SENSOR
MULTIPORT FUEL SYSTEM (MFI)13A-18
.
BAROMETRIC PRESSURE SENSOR
A barometric pressure sensor is built into ECM. The barometric
pressure sensor is a semiconductor diffused pressure element
which outputs voltage to ECM according to atmospheric pres
-
sure. ECM uses this output voltage to sense the altitude of the
vehicle and compensates fuel injection volume to achieve the
appropriate air-fuel ratio for that altitude.
.
ENGINE OIL PRESSURE SWITCH
The engine oil pressure switch is installed on the left side of the
cylinder block. The engine oil pressure switch detects whether
the oil pressure is high or low using the contact switch. When
the oil pressure becomes higher than the specified value after
the engine starts, the contact point of the engine oil pressure
switch opens. This allows the ECM to detect the oil pressure is
higher than the specified value. The ECM outputs the OFF sig
-
nal to the combination meter through the CAN and then turns
off the oil pressure warning lamp.
AK602226AD
5V
Knock sensor
Piezoelectric elementECM
AK602575AC
Barometric pressure sensor
(built in ECM)
AK602587AC
Oil
pressure
Contact switch
Page 112 of 241
SENSOR
MULTIPORT FUEL SYSTEM (MFI)13A-19
.
POWER STEERING PRESSURE SWITCH
A power steering pressure switch is installed on the power
steering oil pump. The power steering pressure switch uses a
contact switch to detect the power steering oil pressure. When
power steering oil pressure rises due to operation of the steer
-
ing wheel, the power steering load switch outputs an ON signal
to ECM. ECM performs idle-up according to the voltage and
prevents reduction in engine speed due to power steering load
and so maintains stable idle speed.
.
AK602228
ON
OFF
AD
12
0ONOFF ECM terminal voltage V
Oil pressure:lowOil pressure: high Operating pressure
Oil pressure kPa (in.Hg) Engine oil
pressure switch
ECM
AK601174AF
Power steering
pressure switch
Oil
pressure
AK602213
ON
OFF
AE
Oil pressure:low
Oil pressure: highOperating pressure
Power steering
pressure switch12
0OFF
ON
ECM
ECM
terminal voltage V
Oil pressure kPa (in.Hg)
Page 114 of 241
SENSOR
MULTIPORT FUEL SYSTEM (MFI)13A-21
.
GENERATOR FR TERMINAL
Generator turns ON/OFF the power transistor in the voltage
regulator to adjust current flow in the field coil according to
alternator output current. In this way generator's output voltage
is kept adjusted (to about 14.7 V). The ratio of power transistor
ON time (ON duty) is output from generator FR terminal to
ECM. ECM uses this signal to detect generator's output current
and drives throttle actuator control motor according to output
current (electric load). This prevents change in idle speed due
to electric load and helps maintain stable idle speed.
.
AK602229AD
FR BS
Field coil
IC regulator
GeneratorIgnition switch-IG
Battery
ECM
Page 115 of 241

SENSOR
MULTIPORT FUEL SYSTEM (MFI)13A-22
GENERATOR L TERMINAL
After turning on the ignition switch, the current is input by the
ECM to the generator L terminal. This allows the IC regulator to
be on and the field coil to be excited. When the generator
rotates in this situation, the voltage is excited in the stator coil
and the current is output from B-terminal through the commuta
-
tion diode. Also the generated voltage is input to the voltage
regulator through the commutation diode. After the electric gen
-
eration begins, the current is supplied to the field coil from this
circuit. In addition, the generated voltage is output from the
generator L terminal to the ECM. This allows the ECM to detect
that the electric generation begins. The ECM outputs the ON
signal to the combination meter through the CAN and then
turns off the generator malfunction light.
AK602577
L BS
AC
Battery
GeneratorIC regulator Ignition switch-IG
CAN
communication
Generator
malfunction
light
Combination meterECM
Field coil
Page 116 of 241

ACTUATOR
MULTIPORT FUEL SYSTEM (MFI)13A-23
ACTUATORM2132002000353
INJECTOR
An injector is an injection nozzle with the electromagnetic valve
that injects fuel based on the injection signal sent by ECM. 1
injector is installed in the intake manifold of each cylinder and
fixed to the fuel rail. When electricity flows through the solenoid
coil, the plunger gets sucked in. The ball valve is integrated
with the plunger, and gets pulled together with the plunger till
the fully open position so that the injection hole is fully open
and the fuel gets injected.
Voltage from the battery gets applied from the injector relay to
the injector and up to the ECM. ECM turns ON its power tran
-
sistor and prepares the injector's ground circuit. Thus, current
flows through the injector while power transistor is ON and the
injector injects fuel.
AK602272AC
Fuel
Plate Ball valvePlunger Solenoid coilConnector
Filter
AK602578
From ETACS-ECUFrom MFI relay
Injector relay
Injectors
OFF ON
ECM
AC
No. 1 No. 2 No. 3 No. 4
Page 117 of 241

ACTUATOR
MULTIPORT FUEL SYSTEM (MFI)13A-24
THROTTLE ACTUATOR CONTROL MOTOR
A throttle actuator control motor is installed in throttle body. The
throttle actuator control motor performs the Open/Close of the
throttle valve through the reduction gear. ECM changes current
direction according to the Open/Close direction and also
changes current to the motor coil to control the throttle actuator
control motor.
Throttle actuator control motor is composed of a good
response, low energy, and small DC motor with brush and can
generate rotation force corresponding to the current applied on
the coil. When there is no current passing through the throttle
actuator control motor, the throttle valve remains at a pre
-
scribed opening angle. So, even if current stops because of a
fault in the system, a minimum level of running remains possi
-
ble.
AK604125AB
Throttle body
Throttle actuator
control motor
AK602231
Throttle actuator
control motor
Throttle actuator
control motor relayMFI relay
To ECM
Power supplyOFFON
OFF
ON
AE
From battery
ECM
Page 118 of 241

ACTUATOR
MULTIPORT FUEL SYSTEM (MFI)13A-25
IGNITION COIL
Refer to GROUP 16 − Ignition Coil P.16-2.
EXHAUST GAS RECIRCULATION (EGR) VALVE
Refer to GROUP 17 − Emission Control − Exhaust Gas Recircu-
lation (EGR) System P.17-12.
EVAPORATIVE EMISSION PURGE SOLENOID
Refer to GROUP 17 − Emission Control − Evaporative Emission
Control System
P.17-11.
INTAKE ENGINE OIL CONTROL VALVE
The intake engine oil control valve is installed on the left side of
the cylinder head. Receiving the duty signal from the ECM, the
intake engine oil control valve moves the spool valve position
and divides the oil pressure from the cylinder block into the
advanced chamber and the retarded chamber of the V.V.T.
sprocket as well as continually changes the intake camshaft
phase. The spring makes spool valve stop at the position
where the intake camshaft is at the most retarded angle when
the engine is stopped. The ECM moves the spool valve posi
-
tion by increasing and decreasing ON duty ratio of the intake
engine oil control valve and allows the intake camshaft to be at
the target phase angle. When the duty ratio increases, the
spool valve moves. The sprocket rotates toward the advanced
angle side. When the duty ratio decreases, the sprocket rotates
toward the retarded angle side. When the medium duty ratio, at
which the spool valve is at the medium position, is achieved, all
the oil passages are closed. This allows the phase angle to be
kept constant. The ECM changes and controls the duty ratio in
accordance with the engine operation to get the optimum
phase angle.
AK604740AD
Spool valve movement
Retard
chamber
Spring
Drain
Oil pressureCoil
Plunger
Drain Advance
chamber
AK602579
ECM
Intake engine oil
control valve12VOFF
ON
T50ms
0V
AD
From MFI relay
The longer the ON position, the more
advanced the intake camshaft angle