2009 NISSAN LATIO service

EC-1028< SERVICE INFOMATION >
[MR TYPE 2]
ENGINE CONTROL SYSTEM
*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 engi ne 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 ma ss air flow sensor.
VARIOUS FUEL INJECTION I NCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compens ated 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 ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed*3
Piston position
Fuel injection
& mixture ratio
control Fuel 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) switch Gear position
Battery Battery voltage*3
Knock sensor Engine knocking condition
EPS control unit Power steering operation*2
Heated oxygen sensor 2* 1
Density 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

ENGINE CONTROL SYSTEM
EC-1029
< SERVICE INFOMATION >
[MR TYPE 2] C
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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 the sensor voltage signal. For more information about air
fuel ratio (A/F) sensor 1, refer to EC-1210 . 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 mixture 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 ca rried 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 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 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 fuel injectors will then receive the signals two times for each engine cycle. SEF337W

EC-1036< SERVICE INFOMATION >
[MR TYPE 2]
EVAPORATIVE EMISSION SYSTEM
EVAPORATIVE EMISSION SYSTEM
Description INFOID:0000000004499914
SYSTEM DESCRIPTION
The evaporative emission system is used to reduce hydr ocarbons emitted into the atmosphere from the fuel
system. This reduction of hydrocarbons is accomplis hed by activated charcoals in the EVAP canister.
The fuel vapor in the sealed fuel tank is led into t he EVAP canister which contains activated carbon and the
vapor is stored there when the engine is not oper ating or when refueling to the fuel tank.
The vapor in the EVAP canister is purged by the air through the purge line to the intake manifold when the
engine is operating. EVAP canister purge volume contro l solenoid valve is controlled by ECM. When the
engine operates, the flow rate of vapor controlled by EVAP canister purge volume control solenoid valve is
proportionally regulated as the air flow increases.
EVAP canister purge volume control solenoid valve al so shuts off the vapor purge line during decelerating.
EVAPORATIVE EMISSION LINE DRAWING PBIB3639E

EVAPORATIVE EMISSION SYSTEM
EC-1037
< SERVICE INFOMATION >
[MR TYPE 2] C
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NOTE: Do not use soapy water or any type of so
lvent while installing vacuum hose or purge hoses.
:
Vehicle front
:From next figure
1. Intake manifold collector 2. EVAP canister purge volume con- trol solenoid valve3. EVAP service port
4. EVAP purge resonator PBIB3330E

EC-1038< SERVICE INFOMATION >
[MR TYPE 2]
EVAPORATIVE EMISSION SYSTEM
Component Inspection INFOID:0000000004499915
EVAP CANISTER (A): To previous figure
1. EVAP control system pressure sensor 2. EVAP canister 3. EVAP canister vent control valve
NOTE: Do not use soapy water or any type of so lvent while installing vacuum hose or purge hoses. BBIA0692E

EVAPORATIVE EMISSION SYSTEM
EC-1039
< SERVICE INFOMATION >
[MR TYPE 2] C
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Check EVAP canister as follows:
1. Block port B.
2. Blow air into port Aand check that it flows freely out of port C.
3. Release blocked port B.
4. Apply vacuum pressure to port Band check that vacuum pres-
sure exists at the ports A and C.
5. Block port A and B.
6. Apply pressure to port Cand check that there is no leakage.
FUEL TANK VACUUM RELIEF VALVE (BUILT INTO FUEL FILLER CAP) 1. Wipe clean valve housing.
2. Check valve opening pressure and vacuum.
3. If out of specificat ion, replace fuel filler cap as an assembly.
CAUTION:
Use only a genuine fuel filler cap as a replacement. If an incor-
rect fuel filler cap is used, the MIL may come on.
EVAP CANISTER PURGE VOLUME CONTROL SOLENOID VALVE
Refer to EC-1329, " Component Inspection " .
FUEL TANK TEMPERATURE SENSOR Refer to EC-1273, " Component Inspection " .
EVAP CANISTER VENT CONTROL VALVE Refer to EC-1340, " Component Inspection " .
EVAP CONTROL SYSTEM PRESSURE SENSOR Refer to EC-1350, " Component Inspection " .
EVAP SERVICE PORT PBIB1212E
SEF445Y
Pressure: 15.3 - 20.0 kPa
(0.156 - 0.204 kg/cm 2
, 2.22 - 2.90 psi)
Vacuum: −6.0 to −3.4 kPa
( − 0.061 to −0.035 kg/cm 2
, −0.87 to −0.48 psi) SEF943S

EC-1040< SERVICE INFOMATION >
[MR TYPE 2]
EVAPORATIVE EMISSION SYSTEM
Positive pressure is delivered to the EVAP system through the EVAP
service port. If fuel vapor leak age in the EVAP system occurs, use a
leak detector to locate the leak.
Removal and Installation INFOID:0000000004499916
EVAP CANISTER
Tighten EVAP canister as shown in the figure.
EVAP CANISTER VENT CONTROL VALVE
1. Turn EVAP canister vent control valve counterclockwise.
• Lock (A)
• Unlock (B)
2. Remove the EVAP canister vent control valve.
Always replace O-ring with a new one.
How to Detect Fuel Vapor Leakage INFOID:0000000004499917
CAUTION:
• Never use compressed air or a high pressure pump.
• Do not exceed 4.12 kPa (0.042 kg/cm 2
, 0.6 psi) of pressure in EVAP system.
NOTE:
• Do not start engine.
• Improper installation of EVAP service port adapter to the EVAP service port may cause a leak.
WITH CONSULT-III
1. Attach the EVAP service port adapter securely to the EVAP service port.
2. Also attach the pressure pump and hose to the EVAP service port adapter. SEF462UC
PBIB1214E
PBIB3091E

EVAPORATIVE EMISSION SYSTEM
EC-1041
< SERVICE INFOMATION >
[MR TYPE 2] C
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3. Turn ignition switch ON.
4. Select the “EVAP SYSTEM CLOSE” of “WORK SUPPORT” mode with CONSULT-III.
5. Touch “START”. A bar graph (Pressure indicating display) will appear on the screen.
6. Apply positive pressure to the EVAP system until t he pressure indicator reaches the middle of the bar
graph.
7. Remove EVAP service port adapter and hose with pressure pump.
8. Locate the leak using a leak detector. Refer to EC-1036," Description " .
WITHOUT CONSULT-III
1. Attach the EVAP service port adapter securely to the EVAP ser- vice port.
2. Also attach the pressure pump with pressure gauge to the EVAP service port adapter.
3. Apply battery voltage to the termi nal of EVAP canister vent con-
trol valve (3) to make a closed EVAP system.
• EVAP control system pressure sensor (1)
• EVAP canister (2)
4. To locate the leak, deliver positive pressure to the EVAP system until pressure gauge points reach 1.38 to
2.76 kPa (0.014 to 0.028 kg/cm 2
, 0.2 to 0.4 psi).
5. Remove EVAP service port adapter and hose with pressure pump.
6. Locate the leak using a leak detector. Refer to EC-1036, " Description " . SEF200U
SEF462UC
BBIA0693E