EC-26
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COMPONENT PARTS
BATTERY TEMPERATURE SENSOR
Battery temperature sensor is int
egrated in battery current sensor.
The sensor measures temperature around the battery.
The electrical resistance of the t hermistor decreases as temperature
increases.
*: These data are reference values and are measured between battery temperature
sensor signal terminal and sensor ground.
Malfunction Indicator Lamp (MIL)INFOID:0000000012431296
The MIL is located on the combination meter.
The MIL will illuminate when the ignition switch is turned ON without
the engine running. This is a bulb check.
When the engine is started, the MIL should turn OFF. If MIL remains
ON or continues blinking, the on board diagnostic system detects a
DTC(s) that affects exhaust gas.
For details, refer to EC-57, "
DIAGNOSIS DESCRIPTION : Malfunc-
tion Indicator Lamp (MIL)".
Mass Air Flow SensorINFOID:0000000012431297
The mass air flow sensor (1) is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. The mass air flow sensor controls the temperature of the
hot wire to a certain amount. The heat generated by the hot wire is
reduced as the intake air flows around it. The more air, the greater
the heat loss.
Therefore, the electric current supplied to hot wire is changed to
maintain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.
Oil Pressure Warning LampINFOID:0000000012431298
Oil pressure warning lamp is located on the combination meter.
It indicates the low pressure of the engine oil and the malfunction of
the engine oil pressure system.
Combination meter turns the oil pressure warning lamp ON/OFF
according to the oil pressure warning lamp signal received from
ECM via CAN communication.
For details, refer to EC-43, "
ENGINE PROTECTION CONTROL AT
LOW ENGINE OIL PRESSURE : System Description".
Temperature [°C ( °F)]
Vo l ta g e* (V) Resistance (k
Ω)
25 (77) 3.3331.9 - 2.1
90 (194) 0.9690.222 - 0.258
SEF012P
SAT652J
PBIA9559J
PBIA8559J
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EC-28
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STRUCTURE AND OPERATION
STRUCTURE AND OPERATION
Positive Crankcase VentilationINFOID:0000000012431305
This system returns blow-by gas to the intake manifold.
The positive crankcase ventilation (PCV) valve is prov
ided to conduct crankcase blow-by gas to the intake
manifold.
During partial throttle operation of the engine, the in take manifold sucks the blow-by gas through the PCV
valve.
Normally, the capacity of the valve is sufficient to handle any blow-by and a small amount of ventilating air.
The ventilating air is then drawn from the air inlet tubes into the crankcase. In this process the air passes
through the hose connecting air inlet tubes to rocker cover.
Under full-throttle condition, the manifold vacuum is in sufficient to draw the blow-by flow through the valve.
The flow goes through the hose connection in the reverse direction.
On vehicles with an excessively high blow-by, the valve does not
meet the requirement. This is because some of the flow will go
through the hose connection to the air inlet tubes under all condi-
tions.
PBIB2962E
PBIB1588E
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STRUCTURE AND OPERATIONEC-29
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On Board Refueling Vapor Recovery (ORVR)INFOID:0000000012431306
From the beginning of refueling, the air and vapor insi
de the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The v apor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspectio ns below, be sure to observe the following:
• Put a “CAUTION: FLAMMABL E” sign in workshop.
• Do not smoke while servicing fuel system. Keep open flames and sparks away from work area.
• Be sure to furnish the workshop with a CO
2 fire extinguisher.
CAUTION:
• Before removing fuel line parts, carry out the following procedures:
- Put drained fuel in an explosion-proof containe r and put lid on securely.
- Release fuel pressure from fuel line. Refer to EC-137, "
Work Procedure".
- Disconnect battery ground cable.
• Always replace O-ring when the fu el gauge retainer is removed.
• Do not kink or twist hose and tube when they are installed.
• Do not tighten hose and clamps excessively to avoid damaging hoses.
• After installation, run engine and check for fuel leaks at connection.
• Do not attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically.
Continued refueling may cause fuel overflow, resulting in fuel spray and possibly a fire.
JMBIA1930GB
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EC-30
< SYSTEM DESCRIPTION >[HR16DE]
SYSTEM
SYSTEM
ENGINE CONTROL SYSTEM
ENGINE CONTROL SYSTEM : System DiagramINFOID:0000000012431307
JPBIA5483GB
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ENGINE CONTROL SYSTEM : System DescriptionINFOID:0000000012431308
ECM performs various controls such as fuel
injection control and ignition timing control.
MULTIPORT FUEL INJECTION SYSTEM
Function Reference
Multiport fuel injection system EC-32, "
MULTIPORT FUEL INJECTION SYSTEM : System De-
scription"
Electric ignition system
EC-35, "ELECTRIC IGNITION SYSTEM : System Description"
Air conditioning cut controlEC-37, "AIR CONDITIONING CUT CONTROL : System Descrip-
tion"
CAN communication
EC-38, "CAN COMMUNICATION : System Description"
Cooling fan control EC-38, "COOLING FAN CONTROL : System Description"
Evaporative emission systemEC-40, "EVAPORATIVE EMISSION SYSTEM : System Descrip-
tion"
Intake valve timing control
EC-41, "INTAKE VALVE TIMING CONTROL : System Description"
Exhaust valve timing control EC-42, "EXHAUST VALVE TIMING CO
NTROL : System Descrip-
tion"
Engine protection control at low engine oil pressure EC-43, "ENGINE PROTECTION CONTROL AT LOW ENGINE
OIL PRESSURE : System Description"
Fuel filler cap warning systemEC-44, "FUEL FILLER CAP WARNING SYSTEM : System De-
scription"
Automatic speed control device (ASCD)
EC-45, "AUTOMATIC SPEED CONTROL DEVICE (ASCD) : Sys-
tem Description"
Active grille shutter systemEXT-11, "ACTIVE GRILLE SHUTTER SYSTEM : System Descrip-
tion"
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*1: M/T models
*2: CVT models
*3: This sensor is not used to contro
l the engine system under normal conditions.
*4: ECM determines the start signal status by the signals of engine speed and battery voltage.
*5: This signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). T he amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from the crankshaft position sensor, camshaft position sen-
sor and the mass air flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.
• During warm-up
• When starting the engine
• During acceleration
• Hot-engine operation
• When selector lever position is changed from N to D (CVT models)
• High-load, high-speed operation
• During high engine speed operation
Sensor Input signal to ECM ECM functionActuator
Crankshaft position sensor (POS) Engine speed
*4
Piston position
Fuel injection & mixture
ratio controlFuel injector
Camshaft position sensor (PHASE)
Mass air flow sensor
Amount of intake air
Intake air temperature sensor Intake air temperature
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch
*1
PNP signal
Transmission range switch*2
Battery Battery voltage*4
Knock sensor Engine knocking condition
Heated oxygen sensor 2
*3Density of oxygen in exhaust gas
EPS control unit EPS operation signal
*5
Combination meter
Vehicle speed*5
BCMA/C ON signal*5
Blower fan signal*5
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EC-34
< SYSTEM DESCRIPTION >[HR16DE]
SYSTEM
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback sys
tem provides the best air-fuel mixture ra tio for drivability and emission control.
The three way catalyst (manifold) can better reduce CO, HC and NOx emissions. This system uses A/F sen-
sor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage signal. For more information about A/F sensor 1, refer to
EC-19, "
Air Fuel Ratio Sensor 1". This maintains the mixture ratio within the range of stoichiometric (ideal air-
fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the th ree way catalyst (manifold). Even if the switching
characteristics of A/F sensor 1 shift, the air-fuel ratio is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
• Open Loop Control The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
- Deceleration and acceleration
- High-load, high-speed operation
- Malfunction of A/F sensor 1 or its circuit
- Insufficient activation of heated sensor 1 at low engine coolant temperature
- High engine coolant temperature
- During warm-up
- After shifting from N to D (CVT models)
- When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors t he mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM c ontrols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass ai r flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., fuel injector clogging) directly affect mixture ratio.
Accordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This is
then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value co mpared against the basic injection duration. Fuel trim
includes “short-term fuel trim” and “long-term fuel trim”.
“Short-term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical
value. The signal from A/F sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the the-
oretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich, and an increase in
fuel volume if it is lean.
“Long-term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the “short-term fuel trim” from the central value. Such deviation will occur due to individual engine differ-
ences, wear over time and changes in the usage environment.
PBIB2793E
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FUEL INJECTION TIMING
Two types of systems are used.
• Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycl e according to the firing order. This system is used
when the engine is running.
• Simultaneous Multiport Fuel Injection System
Fuel is injected simultaneously into all four cylinders twice each engine cycle. In other words, pulse signals
of the same width are simultaneously transmitted from the ECM.
The four injectors will then receive the signals two times for each engine cycle.
This system is used when the engine is being started and/or if the fail safe system (CPU) is operating.
FUEL SHUT-OFF
Fuel to each cylinder is cut off during deceleration, operation of the engine at excessively high speeds or oper-
ation of the vehicle at excessively high speeds.
ELECTRIC IGNITION SYSTEM
ELECTRIC IGNITION SYSTEM : System DiagramINFOID:0000000012431311
ELECTRIC IGNITION SYSTEM : System DescriptionINFOID:0000000012431312
INPUT/OUTPUT SIGNAL CHART
SEF337W
JPBIA4883GB
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