engine LEXUS RX450h 2021 Workshop Manual

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.

3766-3. Do-it-yourself maintenance
RX450h
The 12-volt battery is located in the
left-hand side of luggage compart-
ment.
RX450hL
The 12-volt battery is located in the
left-hand side of luggage compart-
ment.
RX450h
1 Lift the deck board and attach the
hook. ( P.331)
NOTICE
■Do not use any fluid other than
washer fluid
Do not use soapy water or engine anti-
freeze instead of washer fluid.
Doing so may cause streaking on the
vehicle’s painted surfaces, as well as
damaging the pump leading to problems
of the washer fluid not spraying.
■Diluting washer fluid
Dilute washer fluid with water as neces-
sary.
Refer to the freezing temperatures listed
on the label of the washer fluid bottle.
12-volt battery
Location
Removing the 12-volt battery
cover

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

4026-3. Do-it-yourself maintenance
6Reinstall the fender liner and install
the 3 fender liner clips.
■Front turn signal lights (vehicles
with single-bea m headlights)
1 Removing the engine compartment
cover. 1
Push the center of the clip.
2 Remove the clip.
2 For the right side only: Remove the
bolt of washer fluid inlet.
3 For the right side only: Open the
cap, remove the bracket , and
move the washer fluid inlet.
A

4046-3. Do-it-yourself maintenance
9Install the engine compartment
cover.
1 Push up center portion
2 Insert
3 Press
■Rear turn signal lights (bulb type)
1 Open the back door and apply pro-
tective tape to the vehicle body
around the taillight.
Use masking tape, etc. Do not use duct
tape, as it may leave residue or damage the
paint when removed.
2Using a flathead screwdriver,
remove the cover.
To prevent scratching the vehicle, wrap the
tip of the flathead scre wdriver with a cloth,
etc.
3 Remove the 2 screws.
4 Remove the taillight unit.
1 Attach 2 long pieces of masking

4177-2. Steps to take in an emergency
7
When trouble arises
Fluid leaks under the vehicle
(Water dripping from the air condi-
tioning after use is normal.)
 Flat-looking tires or uneven tire
wear
 Engine coolant temperature gauge
needle continually points higher
than normal
 Changes in exhaust sound
 Excessive tire squeal when corner-
ing
 Strange noises related to the sus-
pension system
 Pinging or other noises related to
the hybrid system
 Engine missing, stumbling or run-
ning roughly
 Appreciable loss of power
 Vehicle pulls heavily to one side
when braking 
Vehicle pulls heavily to one side
when driving on a level road
 Loss of brake effectiveness, spongy
feeling, pedal almost touches the
floor
If you think something is
wrong
If you notice any of the following
symptoms, your vehicle probably
needs adjustment or repair. Con-
tact your Lexus dealer as soon as
possible.
Visible symptoms
Audible symptoms
Operational symptoms

4187-2. Steps to take in an emergency
■Brake system warning light
■Brake system warning light
■High coolant temperature warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
If a warning light turns on or a warning buzzer sounds
Calmly perform the following actions if any of the warning lights comes on or
flashes. If a light comes on or flashes, bu t then goes off, this does not necessar-
ily indicate a malfunction in the system. However, if this continues to occur,
have the vehicle inspected by your Lexus dealer.
Actions to the warning lights or warning buzzers
Warning lightDetails/Actions
(U.S.A.)
or
(red)
(Canada)
Indicates that:
 The brake fluid level is low; or
 The brake system is malfunctioning
 Immediately stop the vehicle in a safe place and contact your Lexus
dealer. Continuing to drive the vehicle may be dangerous.
Warning lightDetails/Actions
(yellow)
Indicates a malfunction in:
 The regenerative braking system;
 The electronically controlled brake system; or
 The electric parking brake
 Have the vehicle inspected by your Lexus dealer immediately.
Warning lightDetails/Actions
Indicates that the engine coolant temperature is too high
Immediately stop the vehicle in a safe place.
Handling method ( P.454)

4197-2. Steps to take in an emergency
7
When trouble arises
■Hybrid system overheat warning light*(warning buzzer)
*: This light illuminates on the multi-information display.
■Charging system warning light*
*: Except F SPORT models: This light illuminates on the multi-information display.
F SPORT models: This light illuminates on the meter.
■Low engine oil pressure warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■Malfunction indicator lamp
Warning lightDetails/Actions
Indicates the hybrid system has overheated
Stop the vehicle in a safe place.
Handling method ( P.456)
Warning lightDetails/Actions
Indicates a malfunction in the vehicle’s charging system
 Immediately stop the vehicle in a safe place and contact your Lexus
dealer. Continuing to drive the vehicle may be dangerous.
Warning lightDetails/Actions
Indicates that the engine oil pressure is too low
 Immediately stop the vehicle in a safe place and contact your Lexus
dealer.
Warning lightDetails/Actions
(U.S.A.)
or
(Canada)
Indicates a malfunction in:
 The hybrid system;
 The electronic engine control system; or
 The electronic throttle control system;
 Have the vehicle inspected by your Lexus dealer immediately.

4307-2. Steps to take in an emergency
not be charged when the shift lever is in N,
shift the shift lever to P when the vehicle is
stopped.
■If “Traction Battery Needs to be Pro-
tected. Shift into P to Restart.” is dis-
played
This message is displayed when the hybrid
battery (traction battery) charge has
become extremely low because the shift
lever has been left in N for a certain amount
of time.
When operating the vehicle, shift to P and
restart the hybrid system.
■If “Shift Is in N Release Accelerator
Before Shifting” is displayed
Message is displayed when the accelerator
pedal has been depressed and the shift
lever is in N.
Release the accelerator pedal and shift the
shift lever to D or R.
■If “Depress Brake when Vehicle Is
Stopped Hybrid Syst em May Overheat”
is displayed
Message is displayed when the accelerator
pedal is depressed to maintain the vehicle
position when stopped on a upward slope,
etc.
If this continues, th e hybrid system may
overheat.
Release the accelerator pedal and depress
the brake pedal.
■If “Power Turned Off to Save Battery” is
displayed
This message is displayed when the power
was cut off due to the automatic power off
function. The next time the hybrid system is
started, increase the engine speed slightly
and maintain it at that speed for approxi-
mately 5 minutes to recharge the 12-volt
battery.
■If “Headlight System Malfunction Visit
Your Dealer” is displayed
The following systems may be malfunction-
ing. Have the vehicle inspected by your
Lexus dealer immediately.
●The LED headlight system
●AFS (Adaptive Front-lighting System) (if equipped)
●The automatic headlight leveling system
●Automatic High Beam
■If “Radar Cruise Control Unavailable
See Owner's Manual” is displayed
The dynamic radar cruise control with
full-speed range system is suspended tem-
porarily or until the problem shown in the
message is re solved. (causes and coping
methods: P.218)
■If “Radar Cruise Control Unavailable” is
displayed
The dynamic radar cruise control with
full-speed range system cannot be used
temporarily. Use the system when it
becomes available again.
■If a message that indicates the malfunc-
tion of front camera is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.218, 424)
●PCS (Pre-Collision system)
●LTA (Lane Tracing Assist)
●Automatic High Beam
●RSA (Road Sign Assist) (if equipped)
●Dynamic radar cruise control with
full-speed range
■If “Maintenance Required Soon” is dis-
played (U.S.A. only)
Indicates that all maintenance according to
the driven distance on the maintenance
schedule
* should be performed soon.
Comes on approximately 4500 miles
(7200 km) after the message has been
reset. If necessary, perform maintenance.
Please reset the message after the mainte-
nance is performed. ( P.362)
*: Refer to the separate “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the main tenance interval
applicable to your vehicle.
■If “Maintenance Required Visit Your
Dealer” is displayed (U.S.A. only)
Indicates that all mainte nance is required to
correspond to the driven distance on the

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.