2008 NISSAN TEANA coolant temperature

ENGINE CONTROL SYSTEM
EC-25
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
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Component DescriptionINFOID:0000000003856464
1. Fuel level sensor unit and fuel pump
harness connector2. Fuel pressure regulator 3. Fuel level sensor unit and fuel pump
: Vehicle front
JMBIA1385ZZ
Component Reference
A/F sensor 1EC-163, "
Description"
A/F sensor 1 heaterEC-140, "Description"
Accelerator pedal position sensorEC-304, "Description"
ASCD brake switchEC-273, "Description"
ASCD steering switchEC-270, "Description"
Battery current sensorEC-258, "Description"
Camshaft position sensor (PHASE)EC-222, "Description"
Crankshaft position sensor (POS)EC-218, "Description"
Cooling fan motorEC-324, "Description"
Electric throttle control actuatorEC-302, "Description"
Electronic controlled engine mountEC-331, "Description"
Engine coolant temperature sensorEC-157, "Description"
EVAP canister purge volume control solenoid valveEC-231, "Description"
Fuel injectorEC-334, "Description"
Fuel pumpEC-337, "Description"
Heated oxygen sensor 2EC-178, "Description"
Heated oxygen sensor 2 heaterEC-143, "Description"
Ignition coil with power transistorEC-341, "Description"
Intake air temperature sensorEC-154, "Description"
Intake valve timing control solenoid valveEC-146, "Description"
Knock sensorEC-215, "Description"
Mass air flow sensorEC-149, "Description"
PCV valveEC-347, "Description"
Power steering pressure sensorEC-236, "Description"
Power valves 1 and 2EC-351, "Description"
Refrigerant pressure sensorEC-348, "Description"
Stop lamp switchEC-291, "Description"
TCM (VQ35DE engine)
Park/neutral position (PNP) switch (VQ25DE engine)EC-245, "Description"
Throttle control motorEC-300, "Description"

EC-28
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
MULTIPORT FUEL INJECTION 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). 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 (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
 High-load, high-speed operation
 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
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
TCM (VQ35DE engine)
Park/neutral position (PNP) switch (VQ25DE engine)Gear position
Battery
Battery voltage*
3
Knock sensor Engine knocking condition
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit)
VDC/TCS operation command*
2
BCM
Air conditioner operation*2
ABS actuator and electric unit (control unit)
Vehicle speed*2

MULTIPORT FUEL INJECTION SYSTEM
EC-29
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
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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 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-163, "
Description". This maintains the mixture ratio within the range of stoichiometric (ideal air-fuel mix-
ture).
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., 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 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 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.
PBIB3020E

MULTIPORT FUEL INJECTION SYSTEM
EC-31
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
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Component Parts LocationINFOID:0000000003857771
1. Intake valve timing control solenoid
valve (bank 1)2. Intake valve timing control solenoid
valve (bank 2)3. Electronic controlled engine mount
control solenoid valve
4. Fuel injector (bank 2) 5. Cooling fan motor-2 6. A/F sensor 1 (bank 2)
7. Ignition coil (with power transistor)
and spark plug (bank 2)8. Camshaft position sensor (PHASE)
(bank 2)9. Crankshaft position sensor (POS)
10. Engine coolant temperature sensor 11. Cooling fan motor-1 12. ECM
13. Refrigerant pressure sensor 14. Battery current sensor 15. IPDM E/R
16. Mass air flow sensor (with intake air
temperature sensor)17. Electric throttle control actuator 18. Power valve actuator 2 (VQ35DE
models)
19. EVAP canister purge volume control
solenoid valve20. Camshaft position sensor (PHASE)
(bank 1)21. Ignition coil (with power transistor)
and spark plug (bank 1)
22. A/F sensor 1 (bank 1) 23. Fuel injector (bank 1) 24. VIAS control solenoid valve 1 and 2
(VQ35DE models)
25. Power valve actuator 1
JMBIA1373ZZ

EC-36
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
MULTIPORT FUEL INJECTION SYSTEM
Component Description
INFOID:0000000003856468
1. Fuel level sensor unit and fuel pump
harness connector2. Fuel pressure regulator 3. Fuel level sensor unit and fuel pump
: Vehicle front
JMBIA1385ZZ
Component Reference
A/F sensor 1EC-163, "
Description"
Accelerator pedal position sensorEC-304, "Description"
Camshaft position sensor (PHASE)EC-222, "Description"
Crankshaft position sensor (POS)EC-218, "Description"
Engine coolant temperature sensorEC-157, "Description"
Fuel injectorEC-334, "Description"
Heated oxygen sensor 2EC-178, "Description"
Intake air temperature sensorEC-154, "Description"
Knock sensorEC-215, "Description"
Mass air flow sensorEC-149, "Description"
Park/neutral position switchEC-245, "Description"
Power steering pressure sensorEC-236, "Description"
Throttle position sensorEC-160, "Description"

ELECTRIC IGNITION SYSTEM
EC-37
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
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ELECTRIC IGNITION SYSTEM
System DiagramINFOID:0000000003856469
System DescriptionINFOID:0000000003856470
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
Ignition order: 1 - 2 - 3 - 4 - 5 - 6
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 injection pulse width and camshaft position sensor (PHASE) sig-
nal. Computing this information, ignition signals are transmitted to the power transistor.
During the following conditions, the ignition timing is revised 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
JMBIA1493GB
Sensor Input Signal to ECM ECM function Actuator
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 sensor Engine knocking
TCM (VQ35DE engine)
Park/neutral position (PNP) switch (VQ25DE engine)Gear position
ABS actuator and electric unit (control unit)
Vehicle speed*
1

EC-38
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
ELECTRIC IGNITION SYSTEM
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:0000000003857772
1. Intake valve timing control solenoid
valve (bank 1)2. Intake valve timing control solenoid
valve (bank 2)3. Electronic controlled engine mount
control solenoid valve
4. Fuel injector (bank 2) 5. Cooling fan motor-2 6. A/F sensor 1 (bank 2)
7. Ignition coil (with power transistor)
and spark plug (bank 2)8. Camshaft position sensor (PHASE)
(bank 2)9. Crankshaft position sensor (POS)
10. Engine coolant temperature sensor 11. Cooling fan motor-1 12. ECM
13. Refrigerant pressure sensor 14. Battery current sensor 15. IPDM E/R
16. Mass air flow sensor (with intake air
temperature sensor)17. Electric throttle control actuator 18. Power valve actuator 2 (VQ35DE
models)
19. EVAP canister purge volume control
solenoid valve20. Camshaft position sensor (PHASE)
(bank 1)21. Ignition coil (with power transistor)
and spark plug (bank 1)
22. A/F sensor 1 (bank 1) 23. Fuel injector (bank 1) 24. VIAS control solenoid valve 1 and 2
(VQ35DE models)
25. Power valve actuator 1
JMBIA1373ZZ

ELECTRIC IGNITION SYSTEM
EC-43
< FUNCTION DIAGNOSIS >[VQ25DE, VQ35DE]
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Component DescriptionINFOID:0000000003856472
1. Fuel level sensor unit and fuel pump
harness connector2. Fuel pressure regulator 3. Fuel level sensor unit and fuel pump
: Vehicle front
JMBIA1385ZZ
Component Reference
Accelerator pedal position sensorEC-304, "
Description"
Camshaft position sensor (PHASE)EC-222, "Description"
Crankshaft position sensor (POS)EC-218, "Description"
Engine coolant temperature sensorEC-157, "Description"
Ignition signalEC-341, "Description"
Knock sensorEC-215, "Description"
Mass air flow sensorEC-149, "Description"
Park/neutral position switchEC-245, "Description"
Throttle position sensorEC-160, "Description"