Nissan Sentra. Manual — part 337
EC-44
< SYSTEM DESCRIPTION >
[MRA8DE]
SYSTEM
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 speed 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 5,250 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, contributing to the improvement in intake air efficiency and the
generation of high torque.
Engine speed: High speed range
When engine speed is 5,250 rpm or more, ECM turns ON the intake manifold tuning valve motor to open the
intake manifold tuning valve. The length of the effective intake 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.)
Intake Manifold Tuning Valve Operating Condition
ECM opens the intake manifold tuning valve when all of the following conditions are satisfied.
• Engine speed: 5,250 rpm or more
• Engine coolant temperature: -30
°C (-22°F) or more
• Battery voltage: between 11 V and 16 V
ENGINE PROTECTION CONTROL AT LOW ENGINE OIL PRESSURE
ENGINE PROTECTION CONTROL AT LOW ENGINE OIL PRESSURE : System De-
scription
INFOID:0000000009758368
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL CHART
JSBIA2818GB
JPBIA4922GB
SYSTEM
EC-45
< SYSTEM DESCRIPTION >
[MRA8DE]
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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
FUEL FILLER CAP WARNING SYSTEM : System Description
INFOID:0000000009758369
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:
Sensor
Input signal to ECM
ECM function
Actuator
Engine oil pressure sensor
Engine oil 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
JSBIA0797GB
EC-46
< SYSTEM DESCRIPTION >
[MRA8DE]
SYSTEM
• Reset operation is performed by operating the meter control switch on the combination meter. Refer to
- 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 communication. 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
INFOID:0000000009758370
SYSTEM DIAGRAM
INPUT/OUTPUT SIGNAL CHART
JSBIA2814GB
SYSTEM
EC-47
< SYSTEM DESCRIPTION >
[MRA8DE]
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*: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
This system improves engine operation when the air conditioner is used.
Under the following conditions, the air conditioner is turned off.
• When the accelerator pedal is fully depressed.
• 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.
COOLING FAN CONTROL
COOLING FAN CONTROL : System Description
INFOID:0000000009758371
SYSTEM DIAGRAM
Sensor
Input Signal to ECM
ECM function
Actuator
Crankshaft position sensor (POS)
Engine speed
*
Piston position
Air conditioner
cut control
IPDM E/R
↓
Air conditioner relay
↓
Compressor
Camshaft position sensor (PHASE)
Engine coolant temperature sensor
Engine coolant temperature
Accelerator pedal position sensor
Accelerator pedal position
Battery
Battery voltage
*
Refrigerant pressure sensor
Refrigerant pressure
EPS control unit
CAN commu-
nication
EPS operation signal
Combination meter
CAN commu-
nication
Vehicle speed signal
A/C auto amp.
CAN commu-
nication
• A/C ON signal
• Blower fan ON signal
JSBIA2816GB
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