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EC-512
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PRECAUTIONS
•
When measuring ECM signals with a circuit tester, never allow
the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
• Do not operate fuel pump when there is no fuel in lines.
• Tighten fuel hose clamps to the specified torque.
- Fuel level sensor unit and fuel pump (1)
- Fuel pressure regulator (2)
- Fuel level sensor (3)
- Fuel tank temperature sensor (4)
• Do not depress accelerator pedal when starting.
• Immediately after starting, do not rev up engine unnecessar-
ily.
• Do not rev up engine just prior to shutdown.
SEF348N
BBIA0704E
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PRECAUTIONSEC-513
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•
When installing C.B. ham radio or a mobile phone, be sure to
observe the following as it may adversely affect electronic
control systems depending on installation location.
- Keep the antenna as far as possible from the electronic con-
trol units.
- Keep the antenna feeder line more than 20 cm (8 in) away
from the harness of electronic controls.
Do not let them run para llel for a long distance.
- Adjust the antenna and feeder line so that the standing-wave
radio can be kept smaller.
- Be sure to ground the radio to vehicle body.
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EC-514
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PREPARATION
PREPARATION
Special Service ToolINFOID:0000000005532378
The actual shapes of Kent
-Moore tools may differ from those of special service tools illustrated here.
Commercial Service ToolINFOID:0000000005532379
Tool number
(Kent-Moore No.)
Tool name Description
(J-44321)
Fuel pressure gauge
Kit Checking fuel pressure
(J-44321-6)
Fuel pressure adapter Connecting fuel pressure gauge to quick connec-
tor type fuel lines.
KV10118400
Fuel tube adapter Measuring fuel pressure
LEC642
LBIA0376E
PBIB3043E
Tool number
(Kent-Moore No.)
Tool name Description
Leak detector
i.e.: (J-41416) Locating the EVAP leak
EVAP service port
adapter
i.e.: (J-41413-OBD) Applying positive pressure through EVAP service
port
S-NT703
S-NT704
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PREPARATIONEC-515
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Fuel filler cap adapter
i.e.: (MLR-8382)
Checking fuel tank vacuum relief valve opening
pressure
Socket wrench Removing and installing engine coolant tempera-
ture sensor
Oxygen sensor thread
cleaner
i.e.: (J-43897-18)
(J-43897-12) Reconditioning the exhaust system threads before
installing a new oxygen sensor. Use with anti-
seize lubricant shown below.
a: 18 mm diameter with pitch 1.5 mm for Zirco-
nia Oxygen Sensor
b: 12 mm diameter with pitch 1.25 mm for Tita-
nia Oxygen Sensor
Anti-seize lubricant
i.e.: (Permatex
TM
133AR or equivalent
meeting MIL specifica-
tion MIL-A-907) Lubricating oxygen sensor thread cleaning tool
when reconditioning exhaust system threads.
Tool number
(Kent-Moore No.)
Tool name
Description
S-NT815
S-NT705
AEM488
S-NT779
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EC-516
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ENGINE CONTROL SYSTEM
ENGINE CONTROL SYSTEM
SchematicINFOID:0000000005532380
Multiport Fuel Inje
ction (MFI) SystemINFOID:0000000005532381
INPUT/OUTPUT SIGNAL CHART
JPBIA3134GB
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*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent t NISSAN LATIO 2010 Service Repair Manual ENGINE CONTROL SYSTEMEC-517
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*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent t](/manual-img/5/57358/w960_57358-1781.png)
ENGINE CONTROL SYSTEMEC-517
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*1: This sensor is not used to control the engine system under normal conditions.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
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 t he crankshaft position sensor (POS), camshaft position
sensor (PHASE) 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 is changed from N to D (A/T and CVT models)
• High-load, high-speed operation
• During deceleration
• During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
Sensor Input Signal to ECMECM functionActuator
Crankshaft position sensor (POS) Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector
Camshaft position sensor (PHASE)
Mass air flow sensor
Amount of intake air
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) signal Gear position
Battery Battery voltage*
3
Knock sensor Engine knocking condition
EPS control unit Power steering operation*
2
Heated oxygen sensor 2*1Density of oxygen in exhaust gas
Air conditioner switch Air conditioner operation*
2
ABS actuator and electric unit (control unit)
Vehicle speed*2
Combination meter
PBIB3020E
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![NISSAN LATIO 2010 Service Repair Manual EC-518
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ENGINE CONTROL SYSTEM
The mixture ratio feedback system provides the best air/fuel mixture ratio for drivability and emission control.
The three way catalyst (ma NISSAN LATIO 2010 Service Repair Manual EC-518
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ENGINE CONTROL SYSTEM
The mixture ratio feedback system provides the best air/fuel mixture ratio for drivability and emission control.
The three way catalyst (ma](/manual-img/5/57358/w960_57358-1782.png)
EC-518
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ENGINE CONTROL SYSTEM
The mixture ratio feedback system provides the best air/fuel mixture ratio for drivability and emission control.
The three way catalyst (manifold) can then better r
educe CO, HC and NOx emissions. This system uses air
fuel ratio (A/F) sensor 1 in the exhaust manifold to monitor whether the engine operation is rich or lean. The
ECM adjusts the injection pulse width according to t he sensor voltage signal. For more information about air
fuel ratio (A/F) sensor 1, refer to EC-704
. 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 air fuel ratio (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 air fuel ratio (A/F) sensor 1 or its circuit
• Insufficient activation of air fuel ratio (A /F) sensor 1 at low engine coolant temperature
• High engine coolant temperature
• During warm-up
• After shifting from N to D (A/T and CVT models)
• When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixt ure ratio signal transmitted from air fuel ratio (A/F)
sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to
the theoretical mixture ratio as possible. However, the bas ic mixture ratio is not necessarily controlled as orig-
inally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during 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 compensati on used to maintain the mixture ratio at its theoretical
value. The signal from air fuel ratio (A/F) sensor 1 i ndicates whether the mixture ratio is RICH or LEAN com-
pared to the theoretical value. The signal then triggers a r eduction 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 carri ed out long-term to compensate for continual deviation
of the short term fuel trim from t he central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
FUEL INJECTION TIMING
Two types of systems are used.
Sequential Multiport Fuel Injection System
Fuel is injected into each cylinder during each engine cycle 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 fuel injectors will then receive the signals two times for each engine cycle.
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This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
FUE NISSAN LATIO 2010 Service Repair Manual ENGINE CONTROL SYSTEMEC-519
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This system is used when the engine is being started and/or if the fail-safe system (CPU) is operating.
FUE](/manual-img/5/57358/w960_57358-1783.png)
ENGINE CONTROL SYSTEMEC-519
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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.
Electronic Ignition (EI) SystemINFOID:0000000005532382
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM through CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
Firing order: 1 - 3 - 4 - 2
The ignition timing is controlled by the ECM to maintain the best air-fuel ratio for every running condition of the
engine. The ignition timing data is stored in the ECM.
The ECM receives information such as the injecti
on pulse width and camshaft position sensor (PHASE) sig-
nal. Computing this information, ignition si gnals are transmitted to the power transistor.
During the following conditions, the ignition timing is revi sed by the ECM according to the other data stored in
the ECM.
• At starting
• During warm-up
•At idle
• At low battery voltage
• During acceleration
The knock sensor retard system is designed only for emergencies. The basic ignition timing is programmed
within the anti-knocking zone, if recommended fuel is used under dry conditions. The retard system does not
operate under normal driving conditions. If engine knocking occurs, the knock sensor monitors the condition.
The signal is transmitted to the ECM. The ECM retards the ignition timing to eliminate the knocking condition.
Fuel Cut Control (at No Load and High Engine Speed)INFOID:0000000005532383
INPUT/OUTPUT SIGNAL CHART
Sensor Input Signal to ECMECM functionActuator
Crankshaft position sensor (POS) Engine speed*
2
Piston position
Ignition timing
controlPower transistor
Camshaft position sensor (PHASE)
Mass air flow sensor
Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Battery Battery voltage*
2
Knock sensor Engine knocking
Park/neutral position (PNP) signal Gear position
ABS actuator and electric unit (control unit) Vehicle speed*
1Combination meter
SensorInput Signal to ECMECM functionActuator
Park/neutral position (PNP) signal Neutral position
Fuel cut control Fuel injector
Accelerator pedal position sensor
Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE) Engine speed
ABS actuator and electric unit (control unit) Vehicle speed*
Combination meter
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