O2 sensor NISSAN LATIO 2010 Service Repair Manual

EC-38
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MULTIPORT FUEL INJECTION SYSTEM
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 carri ed out over time to compensate for continual deviation
of the short-term fuel trim from the central value. Continual deviation will occur due to individual engine differ-
ences, 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 cy cle according to the ignition order. This system is
used when the engine is running.
• Simultaneous Multiport Fuel Injection System Fuel is injected simultaneously into all four cylinder s 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.
SEF337W
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Component Parts LocationINFOID:0000000005398254
1. Ignition coil (with power transistor)
and spark plug 2. Intake valve timing control solenoid
valve 3. Refrigerant pressure sensor
4. Knock sensor 5. Fuel injector6. Cooling fan motor
7. Camshaft position sensor (PHASE) 8. IPDM E/R 9. ECM
10. Mass air flow sensor (with intake air temperature sensor) 11. Engine coolant temperature sensor 12. Electric throttle control actuator
(with built in throttle position sensor
and throttle control motor)
13. EVAP canister purge volume control solenoid valve
PBIB2939E
Revision: January 20102010 Versa

EC-40
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MULTIPORT FUEL INJECTION SYSTEM
1. Mass air flow sensor
(with intake air temperature sensor) 2. Engine coolant temperature sensor 3. Electric throttle control actuator
4. Camshaft position sensor (PHASE) 5. Ignition coil (with power transistor) 6. Fuel injector
7. EVAP canister purge volume control solenoid valve
Vehicle front
PBIB2940E
Revision: January 20102010 Versa

MULTIPORT FUEL INJECTION SYSTEMEC-41
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1. ECM harness connectors
2. ECM3. IPDM E/R
4. Fuel pump fuse (15A) 5. Intake valve timing control solenoid
valve 6. Knock sensor
7. Refrigerant pressure sensor 8. PCV valve Vehicle front
PBIB2941E
Revision: January 20102010 Versa

EC-42
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MULTIPORT FUEL INJECTION SYSTEM
1. Air fuel ratio (A/F) sensor 1 2. Three way catalyst (Manifold) 3. Heated oxygen sensor 2
4. Three way catalyst (Under floor) 5. Muffler
Vehicle front
1. Exhaust manifold 2. Air fuel ratio (A/F) sensor 1 3. Heated oxygen sensor 2
4. Heated oxygen sensor 2 harness connector
Vehicle front
JMBIA2192ZZ
PBIB2943E
Revision: January 20102010 Versa

MULTIPORT FUEL INJECTION SYSTEMEC-43
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Component DescriptionINFOID:0000000005398255
1. Cooling fan motor harness connec-
tor 2. Crankshaft position sensor 3. Stop lamp switch
4. Brake pedal 5. Accelerator pedal position sensor
harness connector 6. Accelerator pedal position sensor
7. Accelerator pedal 8. Fuel level sensor unit and fuel pump
harness connector (view with in-
spection hole cover removed) 9. Fuel pressure regulator
10. Fuel pump
AWBIA0044ZZ
Component Reference
A/F sensor 1 EC-176, "
Description"
Accelerator pedal position sensorEC-392, "Description"
Camshaft position sensor (PHASE)EC-262, "Description"
Crankshaft position sensor (POS)EC-257, "Description"
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EC-44
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MULTIPORT FUEL INJECTION SYSTEM
Engine coolant temperature sensor
EC-161, "Description"
Fuel injectorEC-423, "Description"
Heated oxygen sensor 2EC-198, "Description"
Intake air temperature sensorEC-156, "Description"
Knock sensorEC-253, "Description"
Mass air flow sensorEC-142, "Description"
Throttle position sensorEC-165, "Description"
Component Reference
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ELECTRIC IGNITION SYSTEMEC-45
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ELECTRIC IGNITION SYSTEM
System DiagramINFOID:0000000005398256
System DescriptionINFOID:0000000005398257
INPUT/OUTPUT SIGNAL CHART
*1: This signal is sent to the ECM via the CAN communication line.
*2: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
Ignition 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
JMBIA2194GB
Sensor Input signal to ECMECM functionActuator
Crankshaft position sensor (POS) Engine speed*
2
Piston position
Ignition timing
controlIgnition coil (with power
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 sensorEngine knocking
Park/neutral position (PNP) switch (M/T)
Transmission range switch (A/T) Gear position
ABS actuator and electric unit (control unit) Vehicle speed*
1Combination meter
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EC-46
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ELECTRIC IGNITION SYSTEM
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.
Component Parts LocationINFOID:0000000005398258
1. Ignition coil (with power transistor)
and spark plug 2. Intake valve timing control solenoid
valve 3. Refrigerant pressure sensor
4. Knock sensor 5. Fuel injector6. Cooling fan motor
7. Camshaft position sensor (PHASE) 8. IPDM E/R 9. ECM
10. Mass air flow sensor (with intake air temperature sensor) 11. Engine coolant temperature sensor 12. Electric throttle control actuator
(with built in throttle position sensor
and throttle control motor)
13. EVAP canister purge volume control solenoid valve
PBIB2939E
Revision: January 20102010 Versa

ELECTRIC IGNITION SYSTEMEC-47
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1. Mass air flow sensor
(with intake air temperature sensor) 2. Engine coolant temperature sensor 3. Electric throttle control actuator
4. Camshaft position sensor (PHASE) 5. Ignition coil (with power transistor) 6. Fuel injector
7. EVAP canister purge volume control solenoid valve
Vehicle front
PBIB2940E
Revision: January 20102010 Versa