2003 NISSAN SENTRA ECU

Parking brake*Check that the lever has the
proper travel and confirm that your vehicle is held
securely on a fairly steep hill with only the parking
brake applied.
Automatic transmission P (Park) position
mechanismCheck that the lock release button
on the shift selector lever operates properly and
smoothly. On a fairly steep hill check that your
vehicle is held securely with the selector lever in
the P position without applying any brakes.
Under the hood and vehicle
The maintenance items listed here should be
checked periodically (for example, each time you
check the engine oil or refuel) .
Windshield washer fluid*Check that there is
adequate fluid in the reservoir.
Engine oil level*Check the level after parking
the vehicle on a level surface with the engine off.
Wait more than 10 minutes for the oil to drain
back into the oil pan.
Brake and clutch fluid levels*Make sure that
the brake and clutch fluid level is between the
MIN and MAX lines on the reservoir.
Power steering fluid level* and linesCheck
the level when the fluid is cold, with the engine
off. Check the lines for proper attachment, leaks,
cracks, etc.Automatic transmission fluid level*Check
the level after putting the selector lever in P with
the engine idling at operating temperature.
Engine coolant level*Check the coolant level
when the engine is cold.
Radiator and hosesCheck the front of the
radiator and clean off any dirt, insects, leaves,
etc., that may have accumulated. Make sure the
hoses have no cracks, deformation, rot or loose
connections.
Engine drive belts*Make sure the drive belts
are not frayed, worn, cracked or oily.
Battery*Check the fluid level in each cell. It
should be between the MAX and MIN lines. Ve-
hicles operated in high temperatures or under
severe conditions require frequent checks of the
battery fluid level.
Exhaust systemMake sure there are no loose
supports, cracks or holes. If the sound of the
exhaust seems unusual or there is a smell of
exhaust fumes, immediately have the exhaust
system inspected by a NISSAN dealer. See the
carbon monoxide warning in the “Starting and
driving” section of this manual.
UnderbodyThe underbody is frequently ex-
posed to corrosive substances such as those
used on icy roads or to control dust. It is very
important to remove these substances from theunderbody, otherwise rust may form on the floor
pan, frame, fuel lines and exhaust system. At the
end of winter, the underbody should be thor-
oughly flushed with plain water, in those areas
where mud and dirt may have accumulated. See
the “Appearance and care” section of this
manual.
Fluid leaksCheck under the vehicle for fuel, oil,
water or other fluid leaks after the vehicle has
been parked for a while. Water dripping from the
air conditioner after use is normal. If you should
notice any leaks or if gasoline fumes are evident,
check for the cause and have it corrected imme-
diately.
8-4Maintenance and do-it-yourself
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When performing any inspection or maintenance
work on your vehicle, always take care to prevent
serious accidental injury to yourself or damage to
the vehicle. The following are general precau-
tions which should be closely observed.
WARNING
cPark the vehicle on a level surface, ap-
ply the parking brake securely and
block the wheels to prevent the vehicle
from moving. For manual transmission
models, move the shift lever to N (Neu-
tral) . For automatic transmission mod-
els, move the selector lever to P (Park) .
cBe sure the ignition key is in the OFF or
LOCK position when performing any
parts replacement or repairs.
cNever leave the engine or automatic
transmission related component har-
nesses disconnected while the ignition
switch is in the ON position.
cNever connect or disconnect the battery
or any transistorized component while
the ignition switch is in the ON position.cYour vehicle is equipped with an auto-
matic engine cooling fan. It may come
on at any time without warning, even if
the ignition key is in the OFF position
and the engine is not running. To avoid
injury, always disconnect the negative
battery cable before working near the
fan.
cIf you must work with the engine run-
ning, keep your hands, clothing, hair
and tools away from moving fans, belts
and any other moving parts.
cIt is advisable to secure or remove any
loose clothing and remove any jewelry,
such as rings, watches, etc. before
working on your vehicle.
cAlways wear eye protection whenever
you work on your vehicle.
cIf you must run the engine in an en-
closed space such as a garage, be sure
there is proper ventilation for exhaust
gases to escape.
cNever get under the vehicle while it is
supported only by a jack. If it is neces-
sary to work under the vehicle, support
it with safety stands.cKeep smoking materials, flame and
sparks away from the fuel tank and
battery.
cOn gasoline engine models with the
multiport fuel injection (MFI) system,
the fuel filter or fuel lines should be
serviced by a NISSAN dealer because
the fuel lines are under high pressure
even when the engine is off.
CAUTION
cDo not work under the hood while the
engine is hot. Turn the engine off and
wait until it cools down.
cAvoid contact with used engine oil and
coolant. Improperly disposed engine
oil, engine coolant and/or other vehicle
fluids can damage the environment. Al-
ways conform to local regulations for
disposal of vehicle fluid.
This “Maintenance and do-it-yourself” section
gives instructions regarding only those items
which are relatively easy for an owner to perform.
A genuine NISSAN service manual is also avail-
able. See “Owner’s Manual/Service Manual or-
der information” in the “Technical and consumer
information” section of this manual.
MAINTENANCE PRECAUTIONS
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2. Open the drain plug on the engine block.
3. Open the radiator cap to drain the coolant.
cWaste coolant must be disposed of prop-
erly.
cCheck your local regulations.
4. Flush the cooling system by running fresh
water through the radiator.
5. Close the drain plugs on the radiator and the
engine block securely.6. See the “Technical and consumer informa-
tion” section for cooling system capacity. Fill
the radiator slowly with the proper mixture of
coolant and water. Fill the reservoir tank up
to the MAX level.
7. For QG18DE engine only, open and close
the air release plug(s) to release air. Then fill
the radiator again and install the radiator
cap.8. Start the engine, and warm it up until it
reaches normal operating temperature.
Then race the engine two or three times
under no load. Watch the engine coolant
temperature gauge for signs of overheating.
9. Stop the engine. After it completely cools
down, refill the radiator up to the filler open-
ing. Fill the reservoir tank up to the MAX
level.
10. For QG18DE engine only, open and close
the air release plug(s) to release air. Then fill
the radiator again and install the radiator
cap.
11. Check the drain plugs on the radiator and
the engine block for any sign of leakage. For
QG18DE only, also check the air release
plug for any sign of leakage.
QG18DE engine
WDI0171
QG18DE engine
WDI0172
Maintenance and do-it-yourself8-11
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cTry to avoid direct skin contact with
used oil. If skin contact is made, wash
thoroughly with soap or hand cleaner
as soon as possible.
cKeep used engine oil out of reach of
children.
CAUTION
Be careful not to burn yourself. The engine
oil may be hot.
cWaste oil must be disposed of properly.
cCheck your local regulations.
6. Clean and reinstall the drain plug and a new
washer. Securely tighten the drain plug with
a wrench. Do not use excessive force.
Drain plug tightening torque:
22 - 29 ft-lb (29 - 39 N·m)
7. Refill engine with recommended oil through
the oil filler opening, then install the oil filler
cap securely.
See “Capacities and recommended
fuel/lubricants” in the “Technical and con-
sumer information” section of this manual for
drain and refill capacity.
The drain and refill capacity depends on the
oil temperature and drain time. Use thesespecifications for reference only. Always use
the dipstick to determine when the proper
amount of oil is in the engine.
8. Start the engine. Check for leakage around
the drain plug and oil filter. Correct as re-
quired.
9. Turn the engine off and wait more than 10
minutes. Check the oil level with the dipstick.
Add engine oil if necessary.
CHANGING ENGINE OIL FILTER
1. Park the vehicle on a level surface and apply
the parking brake.
2. Turn the engine off.
3. Place a large drain pan under the oil filter.
4. Loosen the oil filter with an oil filter wrench
by turning it counterclockwise. Then remove
the oil filter by turning it by hand.
QG18DE engine
WDI0179
8-14Maintenance and do-it-yourself
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WINDOW WASHER FLUID
RESERVOIR
Fill the window washer fluid reservoir periodically.
Add window washer fluid when the light comes
on (if so equipped) .
To fill the window washer fluid reservoir, lift the
cap off the reservoir tank and pour the window
washer fluid into the tank opening.
Add a washer solvent to the washer for better
cleaning. In the winter season, add a windshield
washer antifreeze. Follow the manufacturer’s in-
structions for the mixture ratio.Refill the reservoir more frequently when driving
conditions require an increased amount of win-
dow washer fluid.
CAUTION
cDo not substitute engine anti-freeze
coolant for window washer solution.
This may result in damage to the paint.
cDo not fill the window washer reservoir
tank with washer fluid concentrates at
full strength. Some methyl alcohol
based washer fluid concentrates may
permanently stain the grille if spilled
while filling the window washer reser-
voir tank.
cPre-mix washer fluid concentrates with
water to the manufacturer’s recom-
mended levels before pouring the fluid
into the window washer reservoir tank.
Do not use the window washer reservoir
tank to mix the washer fluid concen-
trate and water.cKeep the battery surface clean and dry. Any
corrosion should be washed off with a solution
of baking soda and water.
cMake certain the terminal connections are
clean and securely tightened.
cIf the vehicle is not to be used for 30 days or
longer, disconnect the negative (-) battery ter-
minal cable to prevent discharge.
WARNING
cDo not expose the battery to flames or
electrical sparks. Hydrogen gas gener-
ated by the battery is explosive. Do not
allow battery fluid to contact your skin,
eyes, fabrics or painted surfaces. After
touching a battery or battery cap, do not
touch or rub your eyes. Thoroughly
wash your hands. If the acid contacts
your eyes, skin or clothing, immediately
flush with water for at least 15 minutes
and seek medical attention.
cDo not operate the vehicle if the fluid in
the battery is low. Low battery fluid can
cause a higher load on the battery
which can generate heat, reduce bat-
tery life, and in some cases lead to an
explosion.
WDI0187
WINDOW WASHER FLUID BATTERY
8-20Maintenance and do-it-yourself
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1. Visually inspect each belt for signs of un-
usual wear, cuts, fraying or looseness. If the
belt is in poor condition or is loose, have it
replaced or adjusted by a NISSAN dealer.
2. Have the belts checked regularly for condi-
tion and tension in accordance with the
maintenance schedule found in the
“NISSAN Service and Maintenance Guide”.
1. Power steering fluid pump
2. Water pump
3. Generator
4. A/C compressor
5. Crankshaft pulley
6. Auto tensionerREPLACING SPARK PLUGS
WARNING
Be sure the engine and ignition switch are
off and that the parking brake is engaged
securely.
CAUTION
Be sure to use the correct socket to re-
move the spark plugs. An incorrect socket
can damage the spark plugs.
QR25DE engine
WDI0192WDI0193
SPARK PLUGS
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WARNING
cOperating the engine with the air
cleaner removed can cause you or oth-
ers to be burned. The air cleaner not
only cleans the air, it stops the flame if
the engine backfires. If it isn’t there, and
the engine backfires, you could be
burned. Do not drive with the air cleaner
removed, and be careful when working
on the engine with the air cleaner
removed.
cNever pour fuel into the throttle body or
attempt to start the engine with the air
cleaner removed. Doing so could result
in serious injury.
IN-CABIN MICROFILTER (if so
equipped)
The in-cabin microfilter restricts the entry of air-
borne dust and pollen particles and reduces
some objectionable outside odors. The filter is
located behind the glove box. Refer to the
“NISSAN Service and Maintenance Guide” for
change intervals.
To change the filter, perform the following proce-
dure:1. Remove the glove box door by removing the
two lower hinge pins.2. Remove the two screws securing the glove
box frame.
3. Remove the two screws securing the glove
box door latch. Remove the latch by pulling it
down.
4. Remove the glove box frame by pulling it
away from the instrument panel to disen-
gage the retaining clips.
LDI0139LDI0140
Maintenance and do-it-yourself8-25
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Replace the battery in the keyfob as follows:
s1Open the lid using a coin.
s2Remove the battery.
s3Install a new battery with the “+” facing
down.Recommended battery: Sanyo CR2025 or
equivalent.
s4Close the lid securely.
5. Press the LOCK button, then the UNLOCK
button two or three times to check the key-
fob operation.If the battery is removed for any reason
other than replacement, perform step 5.
cAn improperly disposed battery can hurt
the environment. Always confirm local
regulations for battery disposal.
cThe keyfob is water-resistant; however,
if it does get wet, immediately wipe com-
pletely dry.
cThe operational range of the keyfob ex-
tends to approximately 49 ft (15 m) from
the vehicle. This range may vary with
conditions.
FCC Notice:
Changes or modifications not expressly ap-
proved by the manufacturer for compliance
could void the user’s authority to operate
the equipment.
This device complies with Part 15 of the
FCC Rules and RSS-210 of Industry
Canada.
Operation is subject to the following two
conditions: (1) This device may not cause
harmful interference, and (2) this device
must accept any interference received, in-
cluding interference that may cause undes-
ired operation of the device.
WPD0116
KEYFOB BATTERY REPLACEMENT
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