ECU INFINITI QX50 2019 Repair Manual

When performing any inspection or mainte-
nance work on your vehicle, always take care
to prevent serious accidental injury to your-
self or damage to the vehicle. The following
are general precautions which should be
closely observed.
WARNING
∙ Park the vehicle on a level surface, applythe parking brake securely and block the
wheels to prevent the vehicle from mov-
ing. Move the shift lever to P (Park).
∙ Be sure the ignition switch is in the OFF or LOCK position when performing any
parts replacement or repairs.
∙ If you must work with the engine running, keep your hands, clothing, hair and tools
away from moving fans, belts and any
other moving parts.
∙ It is advisable to secure or remove any loose clothing and remove any jewelry,
such as rings, watches, etc. before work-
ing on your vehicle.
∙ Always wear eye protection whenever you work on your vehicle. ∙ Your vehicle is equipped with an auto-
matic engine cooling fan. It may come on
at any time without warning, even if the
ignition switch 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.
∙ If you must run the engine in an enclosed space such as a garage, be sure there is
proper ventilation for exhaust gases to
escape.
∙ Never get under the vehicle while it is supported only by a jack. If it is necessary
to work under the vehicle, support it with
safety stands.
∙ Keep smoking materials, flame and sparks away from the fuel tank and
battery.
∙ Because the fuel lines on gasoline engine models are under high pressure even
when the engine is off, it is recommended
that you visit an INFINITI retailer for ser-
vice of the fuel filter or fuel lines.
CAUTION
∙ Do not work under the hood while theengine is hot. Turn the engine off and
wait until it cools down. ∙ Avoid contact with used engine oil and
coolant. Improperly disposed engine oil,
engine coolant and/or other vehicle flu-
ids can damage the environment. Always
conform to local regulations for disposal
of vehicle fluid.
∙ Never leave the engine or Continuously Variable Transmission (CVT) related
component harnesses disconnected
while the ignition switch is in the ON
position.
∙ Never connect or disconnect the battery or any transistorized component while
the ignition switch is in the ON position.
This “Do-it-yourself” section gives instruc-
tions regarding only those items which are
relatively easy for an owner to perform.
A Genuine INFINITI service manual is also
available. For additional information, refer to
“Owner’s Manual/Service Manual order in-
formation” in the “Technical and consumer
information” section of this manual.
You should be aware that incomplete or im-
proper servicing may result in operating diffi-
culties or excessive emissions, and could af-
fect warranty coverage. If in doubt about any
servicing, it is recommended that you have it
done by an INFINITI retailer.
MAINTENANCE PRECAUTIONS
8-2Do-it-yourself

WARNING
∙ Prolonged and repeated contact withused engine oil may cause skin cancer.
∙ Try to avoid direct skin contact with used oil. If skin contact is made, wash thor-
oughly with soap or hand cleaner as soon
as possible.
∙ Keep used engine oil out of reach of children.
CAUTION
Be careful not to burn yourself. The engine
oil may be hot.
7. 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: 25 ft-lb (34 N·m)
8. Refill engine with recommended oil through the oil filler opening, then install
the oil filler cap securely. For additional information on drain and
refill capacity, refer to “Recommended
fluids/lubricants and capacities” in the
“Technical and consumer information”
section of this manual.
The drain and refill capacity depends on
the oil temperature and drain time. Use
these specifications for reference only.
Always use the dipstick to determine
when the proper amount of oil is in the
engine.CAUTION
Damage to engine caused by improper
maintenance or use of incorrect oil and fil-
ter quality and/or viscosity is not covered
by the INFINITI New Vehicle Limited
Warranty.
9. Start the engine. Check for leakage around the drain plug and oil filter. Cor-
rect as required.
10. 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 andapply the parking brake.
2. Turn the engine off.
3. Remove clips
Aand under-engine pro-
tector.
LDI3182
8-8Do-it-yourself

Add a washer solvent to the washer for bet-
ter cleaning. In the winter season, add a
windshield-washer antifreeze. Follow the
manufacturer’s instructions for the mixture
ratio.
Refill the reservoir more frequently when
driving conditions require an increased
amount of windshield-washer fluid.
Recommended fluid is Genuine NISSAN
Windshield Washer Concentrate Cleaner &
Antifreeze or equivalent.
CAUTION
∙ Do not substitute engine antifreeze cool-ant for windshield-washer fluid. This
may result in damage to the paint.
∙ Do not fill the windshield-washer fluid reservoir with washer fluid concentrates
at full strength. Some methyl alcohol
based washer fluid concentrates may
permanently stain the grille if spilled
while filling the windshield-washer fluid
reservoir. ∙ Pre-mix washer fluid concentrates with
water to the manufacturer’s recom-
mended levels before pouring the fluid
into the windshield-washer fluid reser-
voir. Do not use the windshield-washer
fluid reservoir to mix the washer fluid
concentrate and water. ∙ If the battery is labeled "do not open" it is
maintenance free and battery fluid
should not be checked. It is recom-
mended that you visit an INFINITI retailer
or a qualified specialist workshop to con-
firm the battery’s performance.
∙ Keep the battery surface clean and dry. Clean the battery with a solution of bak-
ing soda and water.
∙ Make certain the terminal connections are clean and securely tightened.
∙ If the vehicle is not to be used for 30 days or longer, disconnect the negative (-) bat-
tery terminal cable to prevent discharge.
NOTE:
Care should be taken to avoid situations
that can lead to potential battery discharge
and potential no-start conditions such as: 1. Installation or extended use of elec-
tronic accessories that consume battery
power when the engine is not running
(Phone chargers, GPS, DVD players,
etc).
2. Vehicle is not driven regularly and/or
only driven short distances.
In these cases, the battery may need to be
charged to maintain battery health.
BATTERY
Do-it-yourself8-11

1. Visually inspect the belt for signs of un-usual wear, cuts, or fraying. If the belt is
in poor condition, have it replaced. It is
recommended that you visit an INFINITI
retailer for this service.
2. Have the belt checked regularly for con- dition.
REPLACING SPARK PLUGS
Iridium-tipped spark plugs
It is not necessary to replace iridium-tipped
Aspark plugs as frequently as conventional
type spark plugs because they last much lon-
ger. Follow the maintenance log shown in the
"Maintenance and schedules" section of this
manual. Do not service iridium-tipped spark
plugs by cleaning or regapping.
∙ Always replace spark plugs with recom-
mended or equivalent ones.
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 remove
the spark plugs. An incorrect socket can
damage the spark plugs.
If replacement is required, it is recommended
that you visit an INFINITI retailer for this
service.
SDI1895
SPARK PLUGS
8-14Do-it-yourself

If any electrical equipment does not operate,
check for an open fuse.
Fuses are used in the passenger and engine
compartment. Spare fuses are provided and
can be found in the passenger compartment
fuse box.
When installing a fuse make sure the fuse is
installed in the fuse box securely.ENGINE COMPARTMENT
WARNING
Never use a fuse of higher or lower amper-
age rating than that specified on the fuse
box cover. This could damage the electrical
system or electronic control units or cause a
fire.If any electrical equipment does not come on,
check for an open fuse.
1. Be sure the ignition switch and the head- light switch are OFF.
2. Open the engine hood.
3. Remove the fuse box cover by pushing the tabs and lifting the cover up.
4. Remove the fuse with the fuse puller. The fuse puller is located in the fuse
block in the passenger compartment.
LDI2997LDI3174
FUSES
Do-it-yourself8-19

3. Replace the battery with a new one.Recommended battery: CR2032 or
equivalent.
∙ Do not touch the internal circuit andelectric terminals as doing so could
cause a malfunction.
∙ Hold the battery by the edges. Holding the battery across the contact points
will seriously deplete the storage ca-
pacity.
∙ Make sure that the + side faces the bottom of the lower part.
4. Close the lid securely as illustrated with
CandD.
5. Operate the buttons to check the opera- tion.
If you need assistance with replacement, it is
recommended that you visit an INFINITI re-
tailer for this service. FCC Notice:
For USA:
This device complies with Part 15 of the FCC
Rules. Operation is subject to the following
two conditions: (1) This device may not
cause harmful interference, and (2) this de-
vice must accept any interference received,
including interference that may cause unde-
sired operation.
Note: Changes or modifications not ex-
pressly approved by the party responsible
for compliance could void the user’s author-
ity to operate the equipment.
For Canada:
This device complies with Industry Canada
licence-exempt RSS standard(s). Operation
is subject to the following two conditions: (1)
this device may not cause interference, and
(2) this device must accept any interference,
including interference that may cause unde-
sired operation of the device.
HEADLIGHTS
For additional information on headlight bulb
replacement, refer to the instructions out-
lined in this section.
Replacing the LED headlight bulb
If LED headlight bulb replacement is re-
quired, it is recommended that you visit an
INFINITI retailer for this service.
FOG LIGHTS (if so equipped)
For additional information on fog light bulb
replacement, refer to the instructions out-
lined in this section.
Replacing the LED fog light bulb
If LED fog light bulb replacement is required,
it is recommended that you visit an INFINITI
retailer for this service.
LIGHTS
Do-it-yourself8-23

CAUTION
∙ Never install tire chains on a puncturedrun-flat tire, as this could damage your
vehicle.
∙ Avoid driving over any projection or pot- hole, as the clearance between the ve-
hicle and the ground is smaller than
normal.
∙ Do not enter an automated car wash with a punctured run-flat tire.
∙ Have the punctured tire inspected by an INFINITI retailer or other authorized re-
pair shop. Replace the tire as soon as pos-
sible if the tire is seriously damaged.
∙ Always use tires of the same type, size, brand, construction (bias, bias-belted or
radial), and tread pattern on all four
wheels. Failure to do so may result in a
circumference difference between tires
on the front and rear axles which will
cause excessive tire wear and may dam-
age the transmission, transfer case and
differential gears (AWD models).
∙ ONLY use spare tires specified for the AWD model. ∙ If excessive tire wear is found, it is recom-
mended that all four tires be replaced
with tires of the same size, brand, con-
struction and tread pattern. The tire
pressure and wheel alignment should also
be checked and corrected as necessary. It
is recommended that you visit an
INFINITI retailer for this service.
TIRE CHAINS
CAUTION
Tire chains/cables should not be installed
on 255/45R20 size tires. Installation of
the tire chains/cables on 255/45R20 size
tires will cause damage to the vehicle. If you
plan to use tire chains/cables, you should
install 235/55R19 size tires on your
vehicle.
Use of tire chains may be prohibited accord-
ing to location. Check the local laws before
installing tire chains. When installing tire
chains, make sure they are the proper size for
the tires on your vehicle and are installed
according to the chain manufacturer’s sug-
gestions. Use only SAE class “S” chains. Class
“S” chains are used on vehicles with restricted
tire to vehicle clearance. Vehicles that can use
Class “S” chains are designed to meet the
minimum clearances between the tire and the closest vehicle suspension or body compo-
nent required to accommodate the use of a
winter traction device (tire chains or cables).
The minimum clearances are determined us-
ing the factory equipped tire size. Other types
may damage your vehicle. Use chain tension-
ers when recommended by the tire chain
manufacturer to ensure a tight fit. Loose end
links of the tire chain must be secured or
removed to prevent the possibility of whip-
ping action damage to the fenders or under-
body. If possible, avoid fully loading your ve-
hicle when using tire chains. In addition, drive
at a reduced speed. Otherwise, your vehicle
may be damaged and/or vehicle handling
and performance may be adversely affected.
Do not use tire chains on dry roads. Driving
with chains in such conditions can cause
damage to the various mechanisms of the
vehicle due to some overstress.
Do-it-yourself8-35

Some day-to-day and regular maintenance is
essential to maintain your vehicle good me-
chanical condition, as well as its emissions
and engine performance.
It is the owner’s responsibility to make sure
that the scheduled maintenance, as well as
general maintenance, is performed.
As the vehicle owner, you are the only one
who can ensure that your vehicle receives
proper maintenance. You are a vital link in the
maintenance chain.
GENERAL MAINTENANCE
General maintenance includes those items
which should be checked during normal day-
to-day operation. They are essential for
proper vehicle operation. It is your responsi-
bility to perform these procedures regularly
as prescribed.
Performing general maintenance checks re-
quires minimal mechanical skill and only a few
general automotive tools.
These checks or inspections can be done by
yourself, a qualified technician or, if you pre-
fer, an INFINITI retailer.
SCHEDULED MAINTENANCE
The maintenance items listed in this section
are required to be serviced at regular inter-
vals. However under severe driving condi-
tions, additional or more frequent mainte-
nance will be required.
WHERE TO GO FOR SERVICE
If maintenance service is required or your
vehicle appears to malfunction, have the sys-
tems checked and serviced. It is recom-
mended that you visit an INFINITI retailer for
this service.
INFINITI technicians are well-trained spe-
cialists and are kept up-to-date with the lat-
est service information through technical bul-
letins, service tips and training programs.
They are completely qualified to work on
INFINITI vehiclesbeforework begins.
You can be confident that an INFINITI retail-
er’s service department can perform the ser-
vice needed to meet the maintenance re-
quirements on your vehicle. During the normal day-to-day operation of
the vehicle, general maintenance should be
performed regularly as prescribed in this sec-
tion. If you detect any unusual sounds, vibra-
tions or smells, be sure to check for the cause
or have it checked promptly. In addition, it is
recommended that you visit an INFINITI re-
tailer if you think that repairs are required.
When performing any checks or maintenance
work, closely observe the “Maintenance pre-
cautions” in the “Do-it-yourself” section of
this manual.
EXPLANATION OF GENERAL
MAINTENANCE ITEMS
Additional information on the following
items with“*”isfound in the “Do-it-
yourself” section of this manual.
Outside the vehicle
The maintenance items listed here should be
performed from time to time, unless other-
wise specified.
Doors and engine hood:
Check that the doors
and engine hood operate properly. Also en-
sure that all latches lock securely. Lubricate
hinges, latches, latch pins, rollers and links if
necessary. Make sure that the secondary
MAINTENANCE REQUIREMENTS GENERAL MAINTENANCE
9-2Maintenance and schedules

latch keeps the hood from opening when the
primary latch is released.
When driving in areas using road salt or other
corrosive materials, check lubrication fre-
quently.
Lights*:Clean the headlights on a regular
basis. Make sure that the headlights, stop
lights, tail lights, turn signal lights, and other
lights are all operating properly and installed
securely. Also check headlight aim.
Road wheel nuts (lug nuts)*: When checking
the tires, make sure no wheel nuts are miss-
ing, and check for any loose wheel nuts.
Tighten if necessary.
Tire rotation*: Tires should be rotated every
7,500 miles (12,000 km). If your vehicle is
equipped with different sized tires in the front
and rear, tires cannot be rotated.
Tires*: Check the pressure with a gauge of-
ten and always prior to long distance trips. If
necessary, adjust the pressure in all tires, in-
cluding the spare, to the pressure specified.
Check carefully for damage, cuts or excessive
wear.
Tire Pressure Monitoring System (TPMS)
transmitter components: Replace the TPMStransmitter grommet seal, valve core and cap
when the tires are replaced due to wear or
age.
Wheel alignment and balance:
If the vehicle
should pull to either side while driving on a
straight and level road, or if you detect un-
even or abnormal tire wear, there may be a
need for wheel alignment.
If the steering wheel or seat vibrates at nor-
mal highway speeds, wheel balancing may be
needed.
For additional information regarding tires, re-
fer to “Important Tire Safety Information”
(US) or “Tire Safety Information” (Canada) in
the INFINITI Warranty Information Booklet.
Windshield: Clean the windshield on a regu-
lar basis. Check the windshield at least every
six months for cracks or other damage. Have
a damaged windshield repaired by a qualified
repair facility.
Windshield wiper blades*: Check for cracks
or wear if they do not wipe properly.
Inside the vehicle
The maintenance items listed here should be
checked on a regular basis, such as when
performing scheduled maintenance, cleaning
the vehicle, etc. Accelerator pedal:
Check the pedal for
smooth operation and make sure the pedal
does not catch or require uneven effort. Keep
the floor mat away from the pedal.
Brake pedal: Check the pedal for smooth op-
eration. If the brake pedal suddenly goes
down further than normal, the pedal feels
spongy or the vehicle seems to take longer to
stop, have your vehicle checked immediately.
It is recommended that you visit an INFINITI
retailer for this service. Keep the floor mat
away from the pedal.
Brakes: Check that the brakes do not pull the
vehicle to one side when applied.
Continuously Variable Transmission (CVT) P
(Park) position mechanism: On a fairly steep
hill check that the vehicle is held securely with
the shift lever in the P (Park) position without
applying any brakes.
Parking brake: Check the parking brake op-
eration regularly. The vehicle should be se-
curely held on a fairly steep hill with only the
parking brake applied. If the parking brake
does not securely hold the vehicle, it is recom-
mended that you visit an INFINITI retailer for
service.
Maintenance and schedules9-3

Seat belts:Check that all parts of the seat
belt system (for example, buckles, anchors,
adjusters and retractors) operate properly
and smoothly, and are installed securely.
Check the belt webbing for cuts, fraying,
wear or damage.
Seats: Check seat position controls such as
seat adjusters, seatback recliner, etc., to en-
sure they operate smoothly and all latches
lock securely in every position. Check that the
head restraints/headrests move up and
down smoothly and the locks (if so equipped)
hold securely in all latched positions.
Steering wheel: Check for changes in the
steering system, such as excessive free play,
hard steering or strange noises.
Warning lights and chimes: Make sure all
warning lights and chimes are operating
properly.
Windshield defroster: Check that the air
comes out of the defroster outlets properly
and in sufficient quantity when operating the
heater or air conditioner.
Windshield wiper and washer*: Check that
the wipers and washer operate properly and
that the wipers do not streak.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).
Battery (except for maintenance free bat-
teries)*: Check the fluid level in each cell. It
should be between the MAX and MIN lines.
Vehicles operated in high temperatures or
under severe conditions require frequent
checks of the battery fluid level.
NOTE:
Care should be taken to avoid situations
that can lead to potential battery discharge
and potential no-start conditions such as:
1. Installation or extended use of elec-
tronic accessories that consume battery
power when the engine is not running
(Phone chargers, GPS, DVD players,
etc.).
2. Vehicle is not driven regularly and/or
only driven short distances.
In these cases, the battery may need to be
charged to maintain battery health.
Brake fluid level*: Make sure that the brake
fluid level is between the MAX and MIN lines
on the reservoir. Engine coolant level*:
Check the coolant level
when the engine is cold.
Engine drive belt*: Make sure the drive belt is
not frayed, worn, cracked or oily.
Engine oil level*: Check the level after parking
the vehicle on a level spot and turning off the
engine. Wait more than 15 minutes for the oil
to drain back into the oil pan.
Exhaust system: Make 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. It is recommended
that you visit an INFINITI retailer for this
service. For additional information, refer to
“Exhaust gas (carbon monoxide)” in the
“Starting and driving” section of this manual.
Fluid leaks: Check 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 fuel fumes
are evident, check for the cause and have it
corrected immediately.
9-4Maintenance and schedules