2020 LEXUS NX300h check engine

3396-2. Maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
6
Maintenance and care
Luggage compartment
ItemsCheck points
12-volt batteryCheck the connections.
(  P.352)
Vehicle interior
ItemsCheck points
Accelerator
pedal
The accelerator pedal
should move smoothly
(without uneven pedal
effort or catching).
Brake pedal
• Does the brake pedal
move smoothly?
• Does the brake pedal have appropriate clear-
ance from the floor?
• Does the brake pedal have the correct amount
of free play?
Brakes
•The vehicle should not pull to one side when the
brakes are applied.
• The brakes should work effectively.
• The brake pedal should not feel spongy.
• The brake pedal should not get too close to the
floor when the brakes
are applied.
Head
restraintsDo the head restraints
move smoothly and lock
securely?
Hybrid trans-
mission “Park”
mechanismWhen parked on a slope
and the shift lever is in P, is
the vehicle securely
stopped?
Indica-
tors/buzzersDo the indicators and
buzzers function properly?
LightsDo all the lights come on?
Parking brake
• Does the parking brake switch operate nor-
mally?
• When parked on a slope and the parking brake is
on, is the vehicle
securely stopped?
Seat belts
• Do the seat belts oper-ate smoothly?
• The seat belts should not be damaged.
SeatsDo the seat controls oper-
ate properly?
Steering
wheel
• Does the steering wheel rotate smoothly?
• Does the steering wheel have the correct amount
of free play?
• There should not be any strange sounds coming
from the steering wheel.
Vehicle exterior
ItemsCheck points
DoorsDo the doors operate
smoothly?
Engine hoodDoes the engine hood lock
system work properly?
Fluid leaks
There should not be any
signs of fluid leakage after
the vehicle has been
parked.
ItemsCheck points

3476-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
6
Maintenance and care
■Removing the engine compart-
ment cover
■Installing the clips
1 Insert
2 Press With the engine at operating tempera-
ture and turned off, check the oil level
on the dipstick.
■Checking the engine oil
1 Park the vehicle on level ground.
After warming up the hybrid sys-
tem, and turning off the engine, wait
more than 5 minutes for the oil to
drain back into the bottom of the
engine.
2 Holding a rag under the end, pull
the dipstick out.
3 Wipe the dipstick clean.
4 Reinsert the dipstick fully with its
protruding areas ( in the illustra-
tion) pointing towards engine.
Engine compartment cover
NOTICE
■After installing an engine compart-
ment cover
Make sure that the cover is securely
installed in its original position.
Checking and adding the engine
oil
A

3486-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
5Holding a rag under the end, pull
the dipstick out and check the oil
level.
Low
Normal
Excessive
Measuring side
6 Wipe the dipstick and reinsert it
fully.
■Checking the oil type and prepar-
ing the items needed
Make sure to check the oil type and
prepare the items needed before add-
ing oil.
 Engine oil selection
P.424
 Oil quantity (Low Full)
1.6 qt. (1.5 L, 1.3 Imp.qt.)
Items
Clean funnel
■Adding engine oil
If the oil level is below or near the low
level mark, add engine oil of the same
type as that already in the engine. 1
Remove the oil filler cap by turning
it counterclockwise.
2 Add engine oil slowly, checking the
dipstick.
3 Install the oil filler cap by turning it
clockwise.
■Engine oil consumption
A certain amount of engine oil will be con-
sumed while driving. In the following situa-
tions, oil consumption may increase, and
engine oil may need to be refilled in
between oil maintenance intervals.
●When the engine is new, for example
directly after purchasing the vehicle or
after replacing the engine
●If low quality oil or oil of an inappropriate
viscosity is used
●When driving at high engine speeds or
with a heavy load, when towing, or when
driving while accelerating or decelerat-
ing frequently
●When leaving the engine idling for a long
time, or when driving frequently through
heavy traffic
■After changing the engine oil
The engine oil maintenance data should be
reset. Perform the following procedures:
1 Press or of the meter control
switches and select .
A
B
C
D

3496-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
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Maintenance and care
2 Press or of the meter control
switches, sele ct the “Vehicle Settings”
and then press .
3 Press or of the meter control
switches, select the “Oil Maintenance”
and then press and hold .
4 Select the “Yes” and push .
“The Data Has Been Reset” is displayed
on the multi-information display.
The coolant level is satisfactory if it is
between the “FULL” and “LOW” lines
on the reservoir when the hybrid sys-
tem is cold.
■Engine coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
(  P.416)
WARNING
■Used engine oil
●Used engine oil contains potentially
harmful contaminants which may
cause skin disorders such as inflamma-
tion and skin cancer, so care should be
taken to avoid prolonged and
repeated contact. To remove used
engine oil from your skin, wash thor-
oughly with soap and water.
●Dispose of used oil and filters only in a
safe and acceptable manner. Do not
dispose of used oil and filters in house-
hold trash, in sewers or onto the
ground. Call your Lexus dealer, ser-
vice station or auto parts store for
information concerning recycling or
disposal.
●Do not leave used engine oil within the
reach of children.
NOTICE
■To prevent serious engine damage
Check the oil level on a regular basis.
■When replacing the engine oil
●Be careful not to spill engine oil on the
vehicle components.
●Avoid overfilling, or the engine could
be damaged.
●Check the oil level on the dipstick
every time you re fill the vehicle.
●Be sure the engine o il filler cap is prop-
erly tightened.
Checking the coolant
A
B
C

3506-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
■Power control unit coolant reser-
voirReservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
■Coolant selection
Only use “Toyota Super Long Life Coolant”
or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite,
and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mix-
ture of 50% coolant and 50% deionized
water.
(Minimum temperature: -31°F [-35°C])
Canada:
“Toyota Super Long Life Coolant” is a mix-
ture of 55% coolant and 45% deionized
water.
(Minimum temperature: -44°F [-42°C])
For more details about coolant, contact
your Lexus dealer.
■If the coolant level drops within a short
time of replenishing
Visually check the radiator, hoses,
engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have your Lexus
dealer test the cap and check for leaks in
the cooling system.
Check the radiator and condenser and
clear away any foreign objects.
If either of the above parts is extremely
dirty or you are not sure of their condi-
tion, have your vehicle inspected by
your Lexus dealer.
A
B
C
WARNING
■When the hybrid system is hot
Do not remove the en gine/power control
unit coolant reservoir caps.
The cooling system may be under pres-
sure and may spray hot coolant if the cap
is removed, causing serious injuries, such
as burns.
NOTICE
■When adding coolant
Coolant is neithe r plain water nor
straight antifreeze. The correct mixture
of water and antifreeze must be used to
provide proper lubrication, corrosion
protection and cooling. Be sure to read
the antifreeze or coolant label.
■If you spill coolant
Be sure to wash it off with water to pre-
vent it from damaging parts or paint.
Checking the radiator and con-
denser
WARNING
■When the hybrid system is hot
Do not touch the radiator or condenser
as they may be hot and cause serious
injuries, such as burns.

3516-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
6
Maintenance and care
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN” lines
on the tank.
■Adding fluid
Make sure to check the fluid type and
prepare the necessary item.
 Fluid type
FMVSS No.116 DOT 3 or SAE J1703;
FMVSS No.116 DOT 4 or SAE J1704
brake fluid
Items
Clean funnel
■Brake fluid can absorb moisture from
the air
Excess moisture in the brake fluid can cause a dangerous loss of braking efficiency. Use
only newly opened brake fluid.
If none of the washer do not work or
the “Windshield Washer Fluid Low” on
the multi-information display, the
washer tank may be empty. Add
washer fluid.
WARNING
■When the electric cooling fans are
operating
Do not touch the engine compartment.
With the power switch in ON mode, the
electric cooling fans may automatically
start to run if the air conditioning is on
and/or the coolant temperature is high.
Be sure the power switch is off when
working near the electric cooling fans or
radiator grille.
Checking and adding the brake
fluid
WARNING
■When filling the reservoir
Take care as brake fluid can harm your
hands and eyes and damage painted sur-
faces.
If fluid gets on your hands or in your eyes,
flush the affected area with clean water
immediately.
If you still experience discomfort, see a
doctor.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go
down slightly as the brake pads wear out
or when the fluid leve l in the accumulator
is high.
If the reservoir needs frequent refilling,
there may be a serious problem.
Checking and adding the washer
fluid

3706-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
1Turn the power switch off.
2 Open the fuse box cover.
Engine compartment: type A fuse
box
Push the tab in and lift the lid off.
Engine compartment: type B fuse
box
Push the tab in and lift the lid off.
Left side instrument panel
Remove the lid.
Luggage compartment
3 Remove the fuse.
Only type A fuse can be removed using the
pullout tool.
4Check if the fuse is blown.
Replace the blown fuse with a new fuse of
an appropriate amperage rating. The
amperage rating can be found on the fuse
box lid.
Checking and replacing
fuses
If any of the electrical components
do not operate, a fuse may have
blown. If this happens, check and
replace the fuses as necessary.
Checking and replacing fuses

3756-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78530_en
6
Maintenance and care
Before replacing, check the wattage of
the light bulb to be replaced. ( P.429)
■Front side marker lights (bulb type)
1 Turn the bulb base counterclock-
wise.
2 Remove the light bulb.
3 When installing, reverse the steps
listed.
■Front turn signal lights (bulb type)
1 Open the hood and remove the
cover for engine compartment
cover. ( P.344, 347)
2 Remove the cover.
Push the center of the clip and remove the clip and cover .
3
Turn the bulb base counterclock-
wise.
4 Remove the light bulb.
5 Replace the light bulb.
Replacing light bulbs
A
B