2021 LEXUS RX450h check engine

3656-2. Maintenance
6
Maintenance and care
Seats• Do the seat controls operate properly?
Steering wheel
• Does the steering wheel rotate
smoothly?
• Does the steering wheel have the cor-
rect amount of free
play?
•There should not be any strange sounds
coming from the
steering wheel.
Vehicle exterior
ItemsCheck points
Doors• Do the doors oper-ate smoothly?
Engine hood
•Does 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
Tires
• Is the tire inflation pressure correct?
• The tires should not be damaged or
excessively worn.
• Have the tires been rotated according to
the maintenance
schedule?
•The wheel nuts should not be loose.
Windshield wip-
ers/rear window
wiper
• The wiper blades should not show any
signs of cracking,
splitting, wear, con-
tamination or defor-
mation.
• The wiper blades should clear the
windshield/rear win-
dow without streak-
ing or skipping.
ItemsCheck points

3716-3. Do-it-yourself maintenance
6
Maintenance and care
Washer fluid tank (P.375)
Brake fluid reservoir ( P.375)
Engine oil level dipstick ( P.372)
Engine coolant reservoir ( P.373)
Power control unit coolant reservoir ( P.373)
Fuse boxes ( P.395)
Radiator ( P.374)
Power control unit coolant radiator ( P.374)
Condenser ( P.374)
Electric cooling fans
Engine oil filler cap ( P.372)
■12-volt battery
 P.376
With the engine at operating tempera-
ture and turned off, check the oil level
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J
K
Checking and adding the engine
oil

3726-3. Do-it-yourself maintenance
on the dipstick.
■Checking the engine oil
1 Park the vehicle on level ground.
After warming up the engine and
turning off the hybrid system, 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.
5 Holding a rag under the end, pull
the dipstick out and check the oil
level.
Low
Normal
Excessive
The shape of the dipstick may differ
depending on the type of vehicle or
engine.
6Wipe the dipstick and reinsert it
fully.
■Checking the oil type and prepar-
ing the item needed
Make sure to check the oil type and
prepare the items needed before add-
ing oil.
 Engine oil selection
P.463
 Oil quantity (Low  Full)
1.9 qt. (1.8 L, 1.6 Imp. qt.)
 Item
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.
A
B
C

3736-3. Do-it-yourself maintenance
6
Maintenance and care
●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 accelera ting 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 maintena nce data should be
reset. Perform the following procedures:
1 Press or of the meter control
switch to select on the multi-infor-
mation display.
2 Press or of the meter control
switch, select the “Vehicle Settings”
then “Oil Maintenance”. (To confirm
setting, press .)
3 Select the “Yes” and press .
4 A message is displayed on the
multi-information display.
■Engine coolant reservoir
The coolant level is satisfactory if it is
between the “FULL” and “LOW” lines
on the reservoir when the hybrid sys-
tem is cold.
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
( P.454)
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, service 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

3746-3. Do-it-yourself maintenance
■Power control unit coolant reser-
voir
The coolant level is satisfactory if it is
between the “FULL” and “LOW” lines
on the reservoir when the hybrid sys-
tem is cold.
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
( P.454)
■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 and radiator
cap.
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

3756-3. Do-it-yourself maintenance
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
brake fluid
Item
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 any washer does not work or the
warning message appears on the
multi-information display, the washer
tank may be empty. Add washer fluid.
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.
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.
Washer fluid
WARNING
■When adding washer fluid
Do not add washer fluid when the hybrid
system is hot or operating as washer fluid
contains alcohol and may catch fire if
spilled on the engine, etc.

3956-3. Do-it-yourself maintenance
6
Maintenance and care
1Turn the power switch off.
2 Open the fuse box cover.
Engine compartment
Push the tab in and lift the lid off.
Driver’s side instrument panel
Remove the lid.
Luggage compartment (type A fuse
box)
RX450h:
Remove the 12-volt battery cover.
( P.376) RX450hL:
Remove the deck board and side auxiliary
box cover and 12-volt battery cover.
(
 P.376)
Luggage compartment (type B fuse
box)
RX450h:
Remove the terminal cover.
RX450hL:
Remove the terminal cover.
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

4317-2. Steps to take in an emergency
7
When trouble arises
maintenance schedule*.
Comes on approximately 5000 miles
(8000 km) after the message has been
reset. (The indicator will not work properly
unless the message ha s been reset.) Per-
form the necessary maintenance. Please
reset the message after the maintenance is
performed. ( P.362)
*: Refer to the separa te “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the maintenance interval
applicable to your vehicle.
■If “Oil Maintenance Required Soon” is
displayed
Indicates that the engine oil should be
scheduled to be changed.
Check the engine oil and change it if neces-
sary. After changing the engine oil, make
sure to reset the message. ( P.373)
■If “Oil Maintenance Required” is dis-
played
Indicates that the engine oil should be
changed.
Check and change the en gine oil, and oil fil-
ter by your Lexus deal er. After changing the
engine oil, make sure to reset the message.
(  P.373)
■If a message that in dicates the need for
visiting your Lexus dealer is displayed
The system or part shown on the
multi-information display is malfunctioning.
Have the vehicle inspected by your Lexus
dealer immediately.
■If a message that in dicates the need for
referring to Owner’s Manual is dis-
played
●“Engine Coolant Temp High” is shown on
the multi-information display, follow the
instructions. ( P.454)
●If any of the following messages are
shown on the multi-information display, it
may indicate a malfunction. Have the
vehicle inspected by your Lexus dealer
immediately.
• “Access System with Elec. Key Malfunc-
tion”
• “Hybrid System Malfunction” •“Check Engine”
• “Hybrid Battery System Malfunction”
• “Accelerator System Malfunction”
●If any of the following messages are
shown on the multi-info
rmation display, it
may indicate a malfun ction. Immediately
stop the vehicle and contact your Lexus
dealer.
• “Braking Power Low”
• “Charging System Malfunction”
• “Oil Pressure Low”
NOTICE
■If “High Power Consumption Partial
Limit On AC/Heater Operation” is
displayed frequently
There is a possible malfunction relating
to the charging system or the 12-volt bat-
tery may be deteriorating. Have the vehi-
cle inspected by your Lexus dealer.