2014 NISSAN TEANA coolant temperature

COMPONENT PARTSEC-23
< SYSTEM DESCRIPTION > [QR25DE]
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EXHAUST COMPARTMENT
BODY COMPARTMENT
Intake valve timing intermediate lock control solenoid valve
EC-30, "Intake Valve Timing Intermediate Lock Control So-lenoid Valve"
Intake valve timing control solenoid valve
EC-30, "Intake Valve Timing Control Solenoid Valve"
Exhaust valve timing control solenoid valveEC-31, "Exhaust Valve Timing Control Solenoid Valve"
Ignition coil (with power transistor)EC-26, "Ignition Coil With Power Transistor"
Engine coolant temperature sensorEC-28, "Engine Coolant Temperature Sensor"
Intake manifold tuning valveEC-31, "Intake Manifold Tuning Valve"
Intake manifold runner control valve position sensor
EC-31, "Intake Manifold Runner Control Valve"
Intake manifold runner control valve actuator
No. Component Function
To engine assembly
JPBIA5841ZZ
No. Component Function
Air fuel ratio (A/F) sensor 1 EC-32, "Air Fuel Ratio (A/F) Sensor 1"
Heated oxygen sensor 2EC-32, "Heated Oxygen Sensor 2"
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

EC-28
< SYSTEM DESCRIPTION >[QR25DE]
COMPONENT PARTS
The mass air flow sensor is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. The MAF sensor controls the temperature of the heater
in sensing element to a certain amount. The temperature distribution
around the heater changes according to the increase in intake air
volume. The change is detected by a thermistor and the air volume
data is sent to ECM by the MAF sensor.
INTAKE AIR TEMPERATURE SENSOR
The intake air temperature sensor is built-into mass air flow sensor. The sensor detects intake air temperature
and transmits a signal to the ECM.
The temperature sensing unit uses a thermistor wh ich is sensitive to the change in temperature.

*: These data are reference values on the diagnosis tool.
Manifold Absolute Pressure SensorINFOID:0000000009462062
The manifold absolute pressure (MAP) sensor is placed at intake
manifold collector. It detects intake manifold pressure and sends the
voltage signal to the ECM.
The sensor uses a silicon diaphragm which is sensitive to the
change in pressure. As the pressure increases, the voltage rises.
NOTE:
The sensor is equipped, but used for trouble diagnosis only.
Engine Coolant Te mperature SensorINFOID:0000000009462063
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
temperature input. The sensor uses a thermistor which is sensitive to
the change in temperature. The elec trical resistance of the ther-
mistor decreases as temperature increases.
PBIA9559J
Intake air temperature
[° C ( °F)] Vo l ta g e* (V)
25 (77) 1.9 – 2.1
80 (176) 3.2 – 3.4
JPBIA4619ZZ
JPBIA5280ZZ
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COMPONENT PARTSEC-29
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*: These data are reference values and are measured between ECM terminals.
Crankshaft Position Sensor (POS)INFOID:0000000009462064
The crankshaft position sensor (POS
) is located on the oil pan facing
the gear teeth (cogs) of the signal pl ate. It detects the fluctuation of
the engine revolution.
The sensor consists of a permanent magnet and Hall IC.
When the engine is running, the high and low parts of the teeth
cause the gap with the sensor to change.
The changing gap causes the magnet ic field near the sensor to
change.
Due to the changing magnetic fiel d, the voltage from the sensor
changes.
The ECM receives the voltage signal and detects the fluctuation of
the engine revolution.
ECM receives the signals as shown in the figure.
Camshaft Position Sensor (PHASE)INFOID:0000000009462065
The camshaft position sensor (PHASE) senses the retraction of
intake camshaft to identify a particular cylinder. The camshaft posi-
tion sensor (PHASE) senses the piston position.
When the crankshaft position sensor (POS) system becomes inoper-
ative, the camshaft position sensor (PHASE) provides various con-
trols of engine parts instead, utilizing timing of cylinder identification
signals.
The sensor consists of a permanent magnet and Hall IC.
When engine is running, the high and low parts of the teeth cause
the gap with the sensor to change.
The changing gap causes the magnet ic field near the sensor to
change.
Due to the changing magnetic field, the voltage from the sensor changes.
Engine coolant temperature
[° C ( °F)] Vo l ta g e* (V)
Resistance (k
Ω)
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.37 - 2.63
50 (122) 2.2 0.68 - 1.00
90 (194) 1.0 0.236 - 0.260
SEF012P
JPBIA5848ZZ
JMBIA0714GB
JPBIA5846ZZ
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

EC-32
< SYSTEM DESCRIPTION >[QR25DE]
COMPONENT PARTS
Air Fuel Ratio (A/F) Sensor 1
INFOID:0000000009462072
The sensor element of the A/F sensor 1 is composed an electrode
layer, which transports ions. It has a heater in the element.
The sensor is capable of precise measurement = 1, but also in the lean and rich range. Together with its
control electronics, the sensor outputs a cl ear, continuous signal throughout a wide range.
The exhaust gas components diffuse through the diffusi on layer at the sensor cell. An electrode layer is
applied voltage, and this current relati ve oxygen density in lean. Also this current relative hydrocarbon density
in rich.
Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this
electrode layer of current. In additi on, a heater is integrated in the
sensor to ensure the required operating temperature of approxi-
mately 760 °C (1,400 °F).
A/F SENSOR 1 HEATER
A/F sensor 1 heater is integrated in the sensor.
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F s ensor 1 element within the specified range.
Heated Oxygen Sensor 2INFOID:0000000009462073
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air fuel ratio is controlled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1 V in richer conditions to 0 V in leaner con-
ditions.
Under normal conditions the heated ox ygen sensor 2 is not used for
engine control operation.
HEATED OXYGEN SENSOR 2 HEATER
Heated oxygen sensor 2 heater is integrated in the sensor.
The ECM performs ON/OFF control of the heated oxy gen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
JPBIA4038GB
JPBIA5446GB
SEF327R
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

EC-34
< SYSTEM DESCRIPTION >[QR25DE]
COMPONENT PARTS

*: These data are reference values and are measured between ECM terminals.
Cooling FanINFOID:0000000009462077
The ECM controls the cooling fan corresponding to the
vehicle speed, engine coolant temperature, refrigerant
pressure, and air conditioner ON signal. The control system has 4-step control [HIGH/MIDDLE/LOW/OFF].
Cooling fan operates at each speed when the current flows in the cooling fan motor.
Refer to EC-59, "COOLING FAN CONTROL : System De scription (with automatic air conditioner)"
for cooling
fan operation.
EVAP CanisterINFOID:0000000009462078
EVAP canister stores the generat ed fuel vapors in the sealed fuel
tank to activated charcoals of EVAP canister when the engine is not
operating or when refueling to the fuel tank.
EVAP Canister Purge Volume Control Solenoid ValveINFOID:0000000009462079
The EVAP canister purge volume control solenoid valve uses a ON/
OFF duty to control the flow rate of fuel vapor from the EVAP canis-
ter. The EVAP canister purge volume control solenoid valve is
moved by ON/OFF pulses from the ECM. The longer the ON pulse,
the greater the amount of fuel vapor that will flow through the valve.
Engine oil temperature
[° C ( °F)] Vol tag e* (V)
Resistance (k
Ω)
–10 (14) 4.4 7.0 - 11.4 20 (68) 3.5 2.37 - 2.63
50 (122) 2.2 0.68 - 1.00
90 (194) 1.0 0.236 - 0.260
110 (230) 0.6 0.143 - 0.153
SEF012P
JPBIA5851ZZ
JMBIA0069ZZ
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

SYSTEMEC-45
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MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system prov
ides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better r educe CO, HC and NOx emissions. This system uses A/F
sensor 1 in the exhaust manifold to monitor whether t he engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage si gnal. For more information about A/F sensor 1, refer to
EC-32, "Air Fuel Ratio (A/F) Sensor 1"
. This maintains the mixture rati o 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 A/F sensor 1 shift, the air-fuel rati o is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
• Open Loop Control
The open loop system condition refers to when the EC M 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 cont rols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture 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 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 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 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.
PBIB2793E
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SYSTEMEC-47
< SYSTEM DESCRIPTION > [QR25DE]
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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 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
• High-load, high-speed operation

• During deceleration
• During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
The mixture ratio feedback system prov ides the best air-fuel mixture ratio for driveability and emission control.
The three way catalyst (manifold) can then better r educe CO, HC and NOx emissions. This system uses A/F
sensor 1 in the exhaust manifold to monitor whether t he engine operation is rich or lean. The ECM adjusts the
injection pulse width according to the sensor voltage si gnal. For more information about A/F sensor 1, refer to
EC-32, "Air Fuel Ratio (A/F) Sensor 1"
. This maintains the mixture rati o 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 A/F sensor 1 shift, the air-fuel rati o is controlled to stoichiometric by the signal from heated
oxygen sensor 2.
• Open Loop Control
The open loop system condition refers to when the EC M 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 cont rols the basic mixture ratio as close to the theoret-
ical mixture ratio as possible. However, the basic mi xture 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 co mpared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
PBIB2793E
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

SYSTEMEC-49
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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.
INTAKE VALVE TIMING CONTROL
INTAKE VALVE TIMING CONTROL : System DescriptionINFOID:0000000009462096
INTAKE VALVE TIMING CONTROL
System Diagram
Input/Output Signal Chart
*: This signal is sent to the ECM through CAN communication line
JPBIA4760GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed and piston position
Intake valve
timing control Intake valve timing control
solenoid valve
Camshaft position sensor (PHASE)
Engine oil temperature sensor Engine oil temperature
Engine coolant temperature sensor Engine coolant temperature
Combination meter Vehicle speed*
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM