NISSAN TEANA 2014 Service Manual

SYSTEMEC-51
< SYSTEM DESCRIPTION > [QR25DE]
C
D E
F
G H
I
J
K L
M A
EC
NP
O
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
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

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
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

SYSTEMEC-53
< SYSTEM DESCRIPTION > [QR25DE]
C
D E
F
G H
I
J
K L
M A
EC
NP
O
SYSTEM DESCRIPTION
This mechanism hydraulically controls cam phases c
ontinuously with the fixed operating angle of the exhaust
valve.
The ECM receives signals such as crankshaft position, camshaft position, engine speed, and engine oil tem-
perature. Then, the ECM sends ON/OFF pulse duty signal s to the exhaust valve timing (EVT) control solenoid
valve depending on driving status. This makes it possible to control the shut/open timing of the exhaust valve
to increase engine torque and output in a range of high engine speed.
INTAKE MANIFOLD RUNNER CONTROL
INTAKE MANIFOLD RUNNER CONTROL : System DescriptionINFOID:0000000009462098
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
Intake manifold runner control valve has a valve portion in the intake passage of each cylinder.
While idling and during low engine coolant temperature, t he intake manifold runner control valve closes. Thus
the velocity of the air in the intake passage increases , promoting the vaporization of the fuel and producing a
intake manifold runner in the combustion chamber.
Because of this operation, this system tends to in crease the burning speed of the gas mixture, improve
exhaust emission, and increase the stability in running conditions.
JPBIA5972GB
JPBIA6226GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

EC-54
< SYSTEM DESCRIPTION >[QR25DE]
SYSTEM
Also, except when idling and during low engine coolant te
mperature, this system opens the intake manifold
runner control valve.
In this condition, this system tends to increase power by improving intake efficiency via reduction of intake flow
resistance.
The intake manifold runner control valve is operated by the ECM.
INTAKE MANIFOLD TUNING SYSTEM
INTAKE MANIFOLD TUNING SYSTEM : System DescriptionINFOID:0000000009462099
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
This system switches the length of intake air path according to the low-to-medium speed range or high speed
range. Torque is increased in the low-to-medium sp eed range and the engine output is improved in the high
speed range.
Engine speed: Low and medium speed range
Since the intake manifold tuning (IMT) valve is closed when the engine speed is less than 5,000 rpm, the
length of the effective intake air path is from the mouth of intake manifold collector to the intake valve. This
long path brings the inertia effect of intake air, cont ributing to the improvement in intake air efficiency and the
generation of high torque.
Engine speed: High speed range
When engine speed is 5,000 rpm or more, ECM turns ON the intake manifold tuning valve motor to open the
intake manifold tuning valve. The length of the effective in take air path at this time is from the intake manifold
tuning valve to the intake valve. This short path brings the inertia effect of intake air in the high speed range,
contributing to the torque improvement while the engine is running at high speeds. (The highest engine output
is improved.)
JPBIA5974GB
JPBIA5935GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

SYSTEMEC-55
< SYSTEM DESCRIPTION > [QR25DE]
C
D E
F
G H
I
J
K L
M A
EC
NP
O
Intake Manifold Tuning Valve Operating Condition
ECM opens the intake manifold tuning valve when all of the following conditions are satisfied.
• Engine speed: 5,000 rpm or more
• Engine coolant temperature: -30 °C (-22 °F) or more
• Battery voltage: 16 V or less
ENGINE PROTECTION CONTROL AT LOW ENGINE OIL PRESSURE
ENGINE PROTECTION CONTROL AT LOW ENGINE OIL PRESSURE : System De-
scription
INFOID:0000000009462100
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL CHART
SYSTEM DESCRIPTION
• The engine protection control at low engine oil pressure warns the driver of a decrease in engine oil pres-
sure by the oil pressure warning lamp a before the engine becomes damaged.
• When detecting a decrease in engine oil pressure at an engine speed less than 1,000 rpm, ECM transmits an oil pressure warning lamp signal to the combination meter.The combination meter turns ON the oil pres-
sure warning lamp, according to the signal.
*: When detecting a normal engine oil pressure, ECM turns OFF the oil pressure warning lamp.
FUEL FILLER CAP WARNING SYSTEM
JPBIA4922GB
Sensor Input signal to ECM ECM function Actuator
Engine oil pressure sensor Engine pressure Engine protection control
• Oil pressure warning lamp
signal
•FUel cut control Combination meter
• Oil pressure warning lamp
Crankshaft position sensor
(POS) Engine speed
Engine oil temperature sensor Engine oil temperature
Decrease in engine oil pressure Engine speed Combination meter
Fuel cut
Oil pressure warning lamp
Detection Less than 1,000 rpm ON* NO
1,000 rpm or more ON YES
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

EC-56
< SYSTEM DESCRIPTION >[QR25DE]
SYSTEM
FUEL FILLER CAP WARNING SYS TEM : System Description
INFOID:0000000009462101
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
The fuel filler cap warning system alerts the driver to the prevention of the fuel filler being left uncapped and
malfunction occurrences after refueling, by turning ON the fuel filler cap warning display on the combination
meter.
ECM judges a refueled state, based on a fuel level signal transmitted from the combination meter.
When a very small leak is detected through the EVAP leak diagnosis performed after judging the refueled
state, ECM transmits a fuel filler cap warning display signal (request for display ON) to the combination meter
via CAN communication.
When receiving the signal, the combination meter turns ON the fuel filler cap warning display.
CAUTION:
Check fuel filler cap installation condition when the fuel filler cap warning display turns ON.
Reset Operation
The fuel filler cap warning lamp tunes OFF, according to any condition listed below:
• Reset operation is performed by operating the meter control switch on the combination meter. Refer to MWI-
18, "Description".
- When the reset operation is performed, the combination meter transmits a fuel filler cap warning reset signal
to ECM via CAN communication. ECM transmits a fuel filler cap warning display signal (request for display
OFF) to the combination meter via CAN communicati on. When receiving the signal, the combination meter
turns OFF the fuel filler cap warning display.
• EVAP leak diagnosis result is normal.
• Fuel refilled.
• DTC erased by using CONSULT.
NOTE:
MIL turns ON if a malfunction is detected in leak diagnosis results again at the trip after the fuel filler cap warn-
ing display turns ON/OFF.
AIR CONDITIONING CUT CONTROL
AIR CONDITIONING CUT CONTROL : System Description (with automatic air condi-
JSBIA0797GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

SYSTEMEC-57
< SYSTEM DESCRIPTION > [QR25DE]
C
D E
F
G H
I
J
K L
M A
EC
NP
O
tioner)INFOID:0000000009462102
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
• When cranking the engine.
• At high engine speeds.
• When the engine coolant temperature becomes excessively high.
• When operating power steering during low engine speed or low vehicle speed.
• When engine speed is excessively low.
• When refrigerant pressure is excessively low or high.
AIR CONDITIONING CUT CONTROL : System Description (with manual air condition-
JPBIA5979GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

EC-58
< SYSTEM DESCRIPTION >[QR25DE]
SYSTEM
er)
INFOID:0000000009462103
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
This system improves engine operati on when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
• When cranking the engine.
• At high engine speeds.
• When the engine coolant temperat ure becomes excessively high.
• When operating power steering during low engine speed or low vehicle speed.
• When engine speed is excessively low.
• When refrigerant pressure is excessively low or high.
COOLING FAN CONTROL
JPBIA6222GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

SYSTEMEC-59
< SYSTEM DESCRIPTION > [QR25DE]
C
D E
F
G H
I
J
K L
M A
EC
NP
O
COOLING FAN CONTROL : System Descripti
on (with automatic air conditioner)
INFOID:0000000009462104
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
ECM controls cooling fan speed corresponding to vehicle speed, engine coolant temperature, refrigerant pres-
sure, air conditioner ON signal. Then control syst em has 4-step control [HIGH/MIDDLE/LOW/OFF].
Cooling Fan Operation
Cooling Fan Relay Operation
The ECM controls cooling fan relays through CAN communication line.
JPBIA3233GB
JMBIA0179GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM

EC-60
< SYSTEM DESCRIPTION >[QR25DE]
SYSTEM
COOLING FAN CONTROL : S ystem Description (with manual air conditioner)
INFOID:0000000009462105
SYSTEM DIAGRAM
SYSTEM DESCRIPTION
ECM controls cooling fan speed corresponding to vehicle speed, engine coolant temperature, refrigerant pres-
sure, air conditioner ON signal. Then control syst em has 4-step control [HIGH/MIDDLE/LOW/OFF].
Cooling fan speed Cooling fan relay
123
Stop (OFF) OFF OFF OFF
Low (LOW) ON OFF OFF
Middle (MID) OFF ON OFF
High (HI) OFF ON ON
JPBIA6223GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM