Nissan Pathfinder (2010 year). Manual — part 303
EC-516
< FUNCTION DIAGNOSIS >
[VK56DE]
ENGINE CONTROL SYSTEM
1.
Body ground (view with air cleaner
case removed)
2.
Body ground (view with battery re-
moved)
3.
No.1 ignition coil
4.
Engine ground
5.
Mass air flow sensor (with intake air
temperature sensor)
6.
IPDM E/R
7.
Battery
8.
Radiator hose
9.
Camshaft position sensor (PHASE)
AWBIA0081ZZ
2010 Pathfinder
ENGINE CONTROL SYSTEM
EC-517
< FUNCTION DIAGNOSIS >
[VK56DE]
C
D
E
F
G
H
I
J
K
L
M
A
EC
N
P
O
10. Electric throttle control actuator
(view with intake air duct removed)
11. Electronic throttle control actuator
harness connector (view with intake
air duct removed)
12. Cooling fan motor harness connec-
tor
: Vehicle front
AWBIA0082ZZ
2010 Pathfinder
EC-518
< FUNCTION DIAGNOSIS >
[VK56DE]
ENGINE CONTROL SYSTEM
1.
EVAP canister purge volume control
solenoid valve (view with engine
cover removed)
2.
EVAP service port
3.
Crankshaft position sensor (POS)
(view from under vehicle)
4.
Engine oil pan
5.
Condenser-1
6.
Brake fluid reservoir
7.
Fuel filler pipe (top of frame view)
8.
EVAP control system pressure sen-
sor
9.
EVAP canister vent control valve
10. EVAP canister
11. Drain filter
12. Refrigerant pressure sensor
13. Intake valve timing control position
sensor (bank 2) (view with engine
cover and intake air duct removed)
14. Intake valve timing control position
sensor (bank 1)
15. Intake valve timing control solenoid
valve (bank 2) (view with engine cov-
er and intake air duct removed)
16. Drive belt
17. Radiator hose (view with engine cov-
er and intake air duct removed)
18
Intake valve timing control solenoid
valve (bank 1)
: Vehicle front
ALBIA0369ZZ
1.
Knock sensor (bank 1) (view with en-
gine removed)
2.
Knock sensor (bank 2) (view with en-
gine removed)
3.
Battery current sensor
4.
Power steering pressure sensor
5.
Intake manifold
6.
Engine coolant temperature sensor
2010 Pathfinder
ENGINE CONTROL SYSTEM
EC-519
< FUNCTION DIAGNOSIS >
[VK56DE]
C
D
E
F
G
H
I
J
K
L
M
A
EC
N
P
O
7.
Ignition coil (with power transistor)
(bank2)
8.
Ignition coil (with power transistor)
(bank 1)
9.
Fuel injector harness connectors
(bank 2)
10. Fuel injector harness connectors
(bank 1)
: Vehicle front
PBIB2710E
1.
A/F sensor 1 (bank 2)
2.
A/F sensor 1(bank 1)
3.
Heated oxygen sensor 2
(bank 1)
4.
Heated oxygen sensor 2
(bank 2)
: Vehicle front
AWBIA0083ZZ
2010 Pathfinder
EC-520
< FUNCTION DIAGNOSIS >
[VK56DE]
ENGINE CONTROL SYSTEM
1.
ASCD steering switch
2.
MAIN switch
3.
CANCEL switch
4.
SET/COAST switch
5.
RESUME/ACCELERATE switch
6.
ECM harness connectors (view with
ECM cover removed)
7.
Coolant reservoir
8.
Accelerator pedal position sensor
9.
Fuel level sensor unit and fuel pump
harness connector (view with fuel
tank removed)
AWBIA0084ZZ
2010 Pathfinder
ENGINE CONTROL SYSTEM
EC-521
< FUNCTION DIAGNOSIS >
[VK56DE]
C
D
E
F
G
H
I
J
K
L
M
A
EC
N
P
O
10. Fuel pump, fuel level sensor unit and
fuel filter
11. Fuel pressure regulator
12. ASCD brake switch
13. Stop lamp switch
14. Brake pedal
2010 Pathfinder
EC-522
< FUNCTION DIAGNOSIS >
[VK56DE]
MULTIPORT FUEL INJECTION SYSTEM
MULTIPORT FUEL INJECTION SYSTEM
System Description
INFOID:0000000005257499
INPUT/OUTPUT SIGNAL CHART
*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This signal is sent to the ECM via the 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). The 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, the camshaft position
sensor 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.
<Fuel increase>
• During warm-up
• When starting the engine
• During acceleration
• Hot-engine operation
• When selector lever position is changed from N to D
• High-load, high-speed operation
<Fuel decrease>
• During deceleration
• During high engine speed operation
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
Knock sensor
Engine knocking condition
Battery
Battery voltage*
3
Power steering pressure sensor
Power steering operation
Heated oxygen sensor 2*
1
Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit)
VDC/TCS operation command*
2
Air conditioner switch
Air conditioner operation*
2
Unified meter control unit
Gear position
Vehicle speed*
2
2010 Pathfinder
MULTIPORT FUEL INJECTION SYSTEM
EC-523
< FUNCTION DIAGNOSIS >
[VK56DE]
C
D
E
F
G
H
I
J
K
L
M
A
EC
N
P
O
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system provides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better reduce 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 A/F
sensor 1, refer to
EC-630, "Component Description"
. This maintains the mixture ratio within the range of sto-
ichiometric (ideal air-fuel mixture).
This stage is referred to as the closed loop control condition.
Heated oxygen sensor 2 is located downstream of the three 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 A/F sensor 1 at low engine coolant temperature
• High engine coolant temperature
• During warm-up
• After shifting from N to D
• When starting the engine
MIXTURE RATIO SELF-LEARNING CONTROL
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from A/F sensor 1.
This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as originally
designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic changes dur-
ing operation (i.e., 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 compared 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 overtime 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.
PBIB3020E
2010 Pathfinder
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