2014 NISSAN TEANA stop start

COMPONENT PARTSEC-27
< SYSTEM DESCRIPTION > [QR25DE]
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The ECM activates the fuel pump for 1 second after the ignition
switch is turned ON to improve engine start ability. If the ECM
receives a engine speed signal from the camshaft position sensor
(PHASE), it knows that the engine is rotating, and causes the pump
to operate. If the engine speed signal is not received when the igni-
tion switch is ON, the engine stalls. The ECM stops pump operation
and prevents battery discharging, thereby improving safety. The
ECM does not directly drive the fuel pump. It sends the control signal
to the fuel pump control module, which in turn controls the fuel
pump.
FUEL LEVEL SENSOR
The fuel level sensor is mounted in the fuel level sensor unit.
The sensor detects a fuel level in the fuel tank and tr ansmits a signal to the combination meter. The combina-
tion meter sends the fuel level sensor signal to the ECM via the CAN communication line.
It consists of two parts, one is mechanical float and the ot her is variable resistor. Fuel level sensor output volt-
age changes depending on the movement of the fuel mechanical float.
Fuel Tank Temperature SensorINFOID:0000000009462060
The fuel tank temperature sensor is used to detect the fuel tempera-
ture inside the fuel tank. The sensor modifies a voltage signal from
the ECM. The modified signal returns to the ECM as the fuel temper-
ature input. The sensor uses a ther mistor which is sensitive to the
change in temperature. The electrical resistance of the thermistor
decreases as temperature increases.

*: These data are reference values and are measured between ECM terminals.
Mass Air Flow Sensor (With Intake Air Temperature Sensor)INFOID:0000000009462061
MASS AIR FLOW SENSOR
JPBIA5842ZZ
Condition Fuel pump operation
Ignition switch is turned to ON. Operates for 1 second.
Engine running and cranking Operates.
When engine is stopped Stops in 1.5 seconds.
Except as shown above Sto ps .
SEF012P
Fluid temperature
[° C ( °F)] Voltage* (V) Resistance (k
Ω)
20 (68) 3.5 2.3 - 2.7
50 (122) 2.2 0.79 - 0.90
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EC-36
< SYSTEM DESCRIPTION >[QR25DE]
COMPONENT PARTS
Battery temperature sensor is int
egrated in battery current sensor.
The sensor measures temperature around the battery.
The electrical resistance of the t hermistor decreases as temperature
increases.

*: These data are reference values and are measured between battery temperature
sensor signal terminal and sensor ground.
Malfunction Indicator lamp (MIL)INFOID:0000000009462083
The Malfunction Indicator lamp (MIL) is located on the combination
meter.
The MIL will illuminate when the ignition switch is turned ON without
the engine running. This is a bulb check.
When the engine is started, the MI L should turn OFF. If the MIL
remains illuminated, the on board diagnostic system has detected an
engine system malfunction.
For details, refer to EC-74, "DIAGNOSIS DESCRIPTION : Malfunc-
tion Indicator Lamp (MIL)".
Oil Pressure Warning LampINFOID:0000000009462084
Oil pressure warning lamp is located on the combination meter.
It indicates the low pressure of the engine oil and the malfunction of
the engine oil pressure system.
Combination meter turns the oil pressure warning lamp ON/OFF
according to the oil pressure warning lamp signal received from
ECM via CAN communication.
For details, refer to EC-55, "ENGINE PROTECTION CONTROL AT
LOW ENGINE OIL PRESSURE : System Description".
Refrigerant Pressure SensorINFOID:0000000009462085
The refrigerant pressure sensor is installed at the c ondenser of the air conditioner system. The sensor uses an
electrostatic volume pressure transducer to convert refrigerant pressure to voltage. The voltage signal is sent
to ECM, and ECM controls cooling fan system.
Stop Lamp Switch & Brake Pedal Position SwitchINFOID:0000000009462086
Stop lamp switch and brake pedal position switch are installed to brake pedal bracket.
ECM detects the state of the brake pedal by those two types of input (ON/OFF signal).
Temperature [°C ( °F)]
Vo l ta g e* (V) Resistance (k
Ω)
25 (77) 3.333 1.9 - 2.1
90 (194) 0.969 0.222 - 0.258
SEF012P
JSBIA1315ZZ
PBIA8559J
PBIB2657E
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

SYSTEMEC-45
< SYSTEM DESCRIPTION > [QR25DE]
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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
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

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-51
< SYSTEM DESCRIPTION > [QR25DE]
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The intake valve timing intermediate lock control improv
es the cleaning ability of exhaust gas at cold starting
by fixing the camshaft sprocket (INT) with two lock keys and bringing the cam phase into intermediate phase.
Cam phase is fixed at the intermediate phase by two lock keys in the camshaft sprocket (INT). Lock key 1 con-
trols retard position and lock key 2 controls advance position.
ECM controls the intermediate phase lock by opening/clos ing the intake valve timing intermediate lock control
solenoid valve to control oil pressure acti ng on the lock key and locking/unlocking the lock key.
Lock/Unlock Activation
When ECM activates the intake valve timing intermediate lock control solenoid valve, oil pressure generated in
the oil pump is drained through the oil pressure path in t he control valve. Since oil pressure is not acted on the
lock key, the lock key position is fixed by the spri ng tension and the cam phase is fixed at the intermediate
phase.
When ECM deactivates the intake valve timing intermediate lock control solenoid valve, unlocking oil pressure
acts on each lock key. Lock key 1 is not released because it is under load due to sprocket rotational force. For
this reason, lock key 2 is released first by being pushed up by unlocking oil pressure. When lock key 2 is
released, some clearance is formed between lock key 1 and the rotor due to sprocket rotational force and
return spring force. Accordingly, lock key 1 is pushed up by unlocking oil pressure and the intermediated
phase lock is released.
When stopping the engine
When the ignition switch is turned from idle state to OFF, ECM receives an ignition switch signal from BCM via
CAN communication and activates the intake valve timing intermediate lock control solenoid valve and drains
oil pressure acting on the lock key before activating the intake valve timing control solenoid valve and operat-
ing the cam phase toward the advance position.
The cam phase is fixed by the lock key when shifting to the intermediated phase and ECM performs Lock
judgment to stop the engine.
When starting the engine
JPBIA6317GB
JPBIA5970GB
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EC-52
< SYSTEM DESCRIPTION >[QR25DE]
SYSTEM
When starting the engine by cold start, ECM judges the
locked/unlocked state when ignition switch is turned
ON. When judged as locked state (fixed at the intermedi ate phase), the intake valve timing intermediate lock
control solenoid valve is activated. Since oil pre ssure does not act on the lock key even when the engine is
started, the cam phase is fixed at the intermediate phas e and the intake valve timing control is not performed.
When the engine stops without locking the cam phase at the intermediate phase due to an engine stall and the
state is not judged as locked, the intake valve timing intermediate lock control solenoid valve and the intake
valve timing control solenoid valve are activated and the cam phase shifts to the advanced position to be
locked at the intermediate phase. Even when not locked in the intermediate lock phase due to no oil pressure
or low oil pressure, a ratchet structure of the camshaft sprocket (INT) rotor allows the conversion to the inter-
mediate phase in stages by engine vibration.
When engine coolant temperature is more than 60 °C, the intake valve timing is controlled by deactivating the
intake valve timing intermediate lock control so lenoid valve and releasing the intermediate phase lock.
When the engine is started after warming up, ECM releas es the intermediate phase lock immediately after the
engine start and controls the intake valve timing.
EXHAUST VALVE TIMING CONTROL
EXHAUST VALVE TIMING CONT ROL : System DescriptionINFOID:0000000009462097
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL CHART
JPBIA4761GB
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS) Engine speed and piston position
Exhaust valve
timing control Exhaust valve timing control
solenoid valve
Camshaft position sensor (PHASE)
Engine oil temperature sensor Engine oil temperature
Exhaust valve timing control position
sensor Exhaust valve timing signal
Combination meter CAN commu-
nication Vehicle speed signal
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EC-80
< SYSTEM DESCRIPTION >[QR25DE]
DIAGNOSIS SYSTEM (ECM)
TP SEN 1-B1
V××
• The throttle position sensor signal volt-age is displayed. • TP SEN 2-B1 signal is convert-
ed by ECM internally. Thus, it
differs from ECM terminal volt-
age signal.
TP SEN 2-B1
××
FUEL T/TMP SE °C or °F • The fuel temperature (determined by the
signal voltage of the fuel tank tempera-
ture sensor) is displayed.
EVAP SYS PRES V • The signal voltage of EVAP control sys-
tem pressure sensor is displayed.
FUEL LEVEL SE V ו The signal voltage of the fuel level sensor
is displayed.
START SIGNAL On/Off • Indicates start signal status [ON/OFF]
computed by the ECM according to the
signals of engine speed and battery volt-
age. • After starting the engine, [OFF]
is displayed regardless of the
starter signal.
CLSD THL POS On/Off ×ו Indicates idle position [ON/OFF] comput-
ed by ECM according to the accelerator
pedal position sensor signal.
AIR COND SIG On/Off ×ו Indicates [ON/OFF] condition of the air
conditioner switch as determined by the
air conditioner signal.
PW/ST SIGNAL On/Off ×ו [ON/OFF] condition of the power steering
system (determined by the signal sent
from EPS control unit) is indicated.
LOAD SIGNAL On/Off ×ו Indicates [ON/OFF] condition from the
electrical load signal.
- On: Rear window defogger switch is ON and/or lighting switch is in 2nd position.
- Off: Both rear window defogger switch
and lighting switch are OFF.
IGNITION SW On/Off ×ו Indicates [ON/OFF] condition from igni-
tion switch signal.
HEATER FAN SW On/Off ו Indicates [ON/OFF] condition from the
heater fan switch signal.
BRAKE SW On/Off • Indicates [ON/OFF] condition from the
stop lamp switch signal.
INJ PULSE-B1 msec • Indicates the actual fuel injection pulse
width compensated by ECM according to
the input signals. • When the engine is stopped, a
certain computed value is indi-
cated.
IGN TIMING BTDC ו Indicates the ignition timing computed by
ECM according to the input signals. • When the engine is stopped, a
certain value is indicated.
CAL/LD VALUE % • “Calculated load value” indicates the val-
ue of the current air flow divided by peak
air flow.
MASS AIRFLOW g/s • Indicates the mass air flow computed by
ECM according to the signal voltage of
the mass air flow sensor.
Monitored item Unit
Monitor Item
Selection
Description Remarks
ECU
IN-
PUT
SIG-
NALS MAIN
SIG-
NAL S
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DIAGNOSIS SYSTEM (ECM)EC-85
< SYSTEM DESCRIPTION > [QR25DE]
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WORK SUPPORT MODE
Work Item
*: This function is not necessary in the usual service procedure.
ACTIVE TEST MODE
Test Item
Work item Condition Usage
IDLE AIR VOL LEARN • The idle air volume that keeps the engine within the spec- ified range is memorized in ECM. When learning the idle air volume
EVAP SYSTEM CLOSE Close the EVAP canister vent control valve in order to make
EVAP system close under the following conditions.
• Ignition switch ON
• Engine not running
• Ambient temperature is above 0 °C (32 °F).
• No vacuum and no high pressure in EVAP system
• Fuel tank temp is more than 0 °C (32 °F).
• Within 10 minutes after starting “EVAP SYSTEM CLOSE”
• When trying to execute “EVAP SYSTEM CLOSE” under the condition except above, CONSULT will discontinue it
and display appropriate instruction.
NOTE:
When starting engine, CONSULT may display “BAT-
TERY VOLTAGE IS LOW. CHARGE BATTERY”, even in
when using a charged battery. When detecting EVAP vapor leak
in the EVAP system
FUEL PRESSURE RELEASE • Fuel pump will st op by touching “START” during idling.
Crank a few times after engine stalls. When releasing fuel pressure from
fuel line
TARGET IGN TIM ADJ* • Idle condition When adjusting target ignition tim- ing
TARGET IDLE RPM ADJ* • Idle condition When setting target idle speed
VIN REGISTRATION • In this mode , VIN is registered in ECM. When registering VIN in ECM
SELF-LEARNING CONT • The coefficient of self-learning control mixture ratio returns to the original coefficient. When clearing mixture ratio self-
learning value
CLSD THL POS LEARN • Ignition on and engine stopped. When learning the throttle valve
closed position
SAVING DATA FOR REPLC CPU In th is mode, save data that is in ECM. When ECM is replaced.
WRITING DATA FOR REPLC CPU In this mode, write data stored by “SAVE DATA FOR CPU
REPLC” in work support mode to ECM. When ECM is replaced.
Test item Condition Judgment Check item (Remedy)
FUEL INJECTION • Engine: Return to the original
trouble condition
• Change the amount of fuel injec- tion using CONSULT. If trouble symptom disappears, see
CHECK ITEM. • Harness and connectors
• Fuel injector
• Air fuel ratio (A/F) sensor 1
ENG COOLANT
TEMP • Engine: Return to the original
trouble condition
• Change the engine coolant tem- perature using CONSULT. If trouble symptom disappears, see
CHECK ITEM. • Harness and connectors
• Engine coolant temperature
sensor
• Fuel injector
PURG VOL CONT/V • Engine: After warming up, run en-
gine at 1,500 rpm.
• Change the EVAP canister purge volume control solenoid valve
opening percent using CON-
SULT. Engine speed changes according
to the opening percent. • Harness and connectors
• Solenoid valve
FUEL/T TEMP SEN • Change the fuel tank temperature using CONSULT.
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