2018 LEXUS RX450h warning light

660 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85UIf 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, but then goes off, this does not necessar-
ily indicate a malfunction in the system . However, if this continues to occur,
have the vehicle inspecte d by your Lexus dealer.
Warning light and warning buzzer list Warning light Warning light/Details/Actions(U.S.A.)
(Canada)
Brake system warning light
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.
Brake system warning light
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. (If equipped)
Charging system warning light
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. (U.S.A.)
(Canada)
Malfunction indicator lamp
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.
SRS warning light
Indicates a malfunction in:
• The SRS airbag system;
• The front passenger occupant classification system; or
• The seat belt pretensioner system
→ Have the vehicle inspected by your Lexus dealer immediately.

6618-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85U (U.S.A.)
(Canada)
ABS warning light
Indicates a malfunction in:
• The ABS; or
• The brake assist system
→ Have the vehicle inspected by your Lexus dealer immediately. (Flashes)
(U.S.A.)
(Flashes)
(Canada)
Parking brake indicator
It is possible that the parking br ake is not fully engaged or released
→ Operate the parking brake switch once again.
This light comes on when the parking brake is not released. If the
light turns off after the parking brak e is fully released, the system is
operating normally. (Flashes)
Brake hold operated indicator
Indicates a malfunction in the brake hold system
→ Have the vehicle inspected by your Lexus dealer immediately.
Electric power steering system warning light (warning buzzer)
Indicates a malfunction in the EPS (Electric Power Steering) sys-
tem
→ Have the vehicle inspected by your Lexus dealer immediately.
LKA indicator
Indicates a malfunction in the LKA (Lane-Keeping Assist)
→ When “Lane Keeping Assist Unavailable” is displayed on the
multi-information display, turn the LKA system off, drive the
vehicle for a short time, and then turn the LKA system back on.
( → P. 301)
When a message other than above is displayed, follow the
instructions displayed in the message.
Slip indicator
When the warning lig ht is illuminated:
Indicates a malfunction in:
• The VSC system;
• The TRAC system;
• The Trailer Sway Control; or
• The hill-start assist control system
→ Have the vehicle inspected by your Lexus dealer immediately.
When the warning light flashes:
Indicates that the ABS, VSC, TR AC or Trailer Sway Control sys-
tem is operatingWarning light Warning light/Details/Actions

662 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U (Flashes or illuminates)
PCS warning light
Indicates a malfunction in the PCS (Pre-Collision System) or that
the system is temporarily unavailable due to the vehicle being
extremely hot/cold, or dirt around a front sensor, etc.
( → P. 296, 671)
→ Follow the instructions displaye d on the multi-information dis-
play. ( → P. 296, 671)
If the PCS (Pre-Collision System ) or VSC (Vehicle Stability Con-
trol) system is disabled, the PC S warning light will illuminate.
→ P. 296 (Flashes)
ICS OFF indicator
When a buzzer sounds:
Indicates a malfunction in the Intelligent Clearance Sonar system
→ Have the vehicle inspected by your Lexus dealer immediately.
When a buzzer does not sound:
Indicates that the system is temporarily unavailable, possibly due to
a sensor being dirty or covered with ice, etc.
→ Clear the dirt, etc.
Low fuel level warning light
Indicates that remaining fuel is approximately 2.9 gal. (11.0 L,
2.4 Imp. gal.) or less
→ Refuel the vehicle.
Driver’s and front passenger’s seat belt reminder light (warning
buzzer)
* 1
Warns the driver and/or front passenger to fasten their seat belts
→ Fasten the seat belt.
If the front passenger’s seat is occupied, the front passenger’s
seat belt also needs to be fastened to make the warning light
(warning buzzer) turn off. (RX450h)
(RX450hL)
Rear passengers’ seat belt reminder light (warning buzzer)
* 2
Warns the rear passengers to fasten their seat belts
→ Fasten the seat belt.
Tire pressure warning light
Indicates the following:
• Low tire pressure due to flat tire;
• Low tire pressure due to natural causes; or
• The tire pressure warnin g system is malfunctioning
→ Immediately stop the vehicle in a safe place.
Handling method ( → P. 664)Warning light Warning light/Details/Actions

6638-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85U* 1
: Driver’s and front passenger’s seat belt warning buzzer:
The driver’s seat belt warning buzzer sounds to alert the driver that his or her seat belt
is not fastened. Once the power switch is turned to ON mode, the buzzer sounds for
6 seconds. If the vehicle reaches a speed of 12 mph (20 km/h), the buzzer sounds
once. If the seat belt is still unfastened af ter 24 seconds, the buzzer will sound inter-
mittently for 10 seconds. Then, if the seat belt is still unfa stened, the buzzer will sound
in a different tone for 20 more seconds.
The front passenger’s seat belt warning buzzer sounds to alert the front passenger
that his or her seat belt is not fastened. Th e buzzer sounds once if the vehicle reaches
a speed of 12 mph (20 km/h). If the seat belt is still unfastened after 24 seconds, the
buzzer will sound intermittently for 10 seconds. Then, if the seat belt is still unfastened,
the buzzer will sound in a different tone for 20 more seconds.
* 2
: Rear passengers’ seat belt warning buzzer:
The rear passengers’ seat belt warning bu zzer sounds to alert the rear passengers
that his or her seat belt is not fastened. The buzzer so unds for 6 seconds after the
vehicle reaches a speed of 20 km/h (12 mph). Then, if the seat belt is still unfastened,
the buzzer will sound in a different tone for 24 more seconds. Master warning light
A buzzer sounds and the warning light comes on and flashes to
indicate that the master warnin g system has dete cted a malfunc-
tion.
→ P. 667Warning light Warning light/Details/Actions

664 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact se nsors (rear), driver’s seat position sensor,
driver’s seat belt buckle sw itch, front passenger occupant classification system (ECU and
sensors), “AIR BAG ON” indicator light, “A IR BAG OFF” indicator light, front passen-
ger’s seat belt buckle switch, driver’s seat belt pretension er, front passenger’s seat belt
pretensioner and force limiter, airbags, in terconnecting wiring and power sources.
( → P. 36) ■
Front passenger detection sensor, seat belt reminder and warning buzzer●
If luggage is placed on the front passenger seat, the front passenger detection sensor
may cause the warning light to flash and the warning buzzer to sound even if a passen-
ger is not sittin g in the seat.●
If a cushion is placed on the seat, the sens or may not detect a passenger, and the warn-
ing light may not operate properly. ■
Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insu fficient or the voltage temporarily drops,
the electric power steering system warning light may come on and the warning buzzer
may sound. ■
If the malfunction indicator lamp comes on while driving
First check the following: ●
Is the fuel tank empty?
If it is, fill the fu el tank immediately.●
Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving trips.
If the light does not go off even after severa l trips, contact your Lexus dealer as soon as
possible. ■
When the tire pressure warning light comes on
Inspect the tires to check if a tire is punctured.
If a tire is punctured: → P. 673
If none of the tires are punctured:
Turn the power switch off then turn it to ON mode. Check if the tire pressure warning
light comes on or blinks. 
If the tire pressure warning light comes on
After the temperature of the tires has lowere d sufficiently, check the inflation pressure
of each tire and adjust th em to the specified level.
If the warning light does not turn off even after several minutes have elapsed, check
that the inflation pressure of each tire is at the specified level an d perform initialization.
( → P. 613)
If the warning light does not turn off severa l minutes after the init ialization has been per-
formed, have the vehicle inspected by your Lexus dealer immediately. 
If the tire pressure wa rning light blinks for 1 minute then stays on
There may be a malfunction in the tire pressure warnin g system. Have the vehicle
inspected by your Lexus dealer immediately. 1
2

6658-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85U■
The tire pressure warning light ma y come on due to natural causes
The tire pressure warning light may come on due to natural causes such as natural air
leaks and tire inflation pressure changes caus ed by temperature. In this case, adjusting
the tire inflation pressure will turn off the warning light (aft er a few minutes).■
When a tire is replaced with a spare tire
The compact spare tire is not equipped with a tire pressure warning valve and transmit-
ter. If a tire goes flat, the tire pressure warning light will not turn off even though the flat
tire has been replaced with the spare tire. Replace the spare tire with the repaired tire
and adjust the tire inflation pressure. The tire pressure warnin g light will go off after a few
minutes. ■
Conditions that the tire pressure wa rning system may not function properly
→ P. 616 ■
Warning buzzer
In some cases, the buzzer ma y not be heard due to being in a noisy location or audio
sound. ■
Customization
Some functions can be customized. ( → P. 736)
WARNING ■
If both the ABS and the brake sy stem warning lights remain on
Stop your vehicle in a safe place immediat ely and contact your Lexus dealer. The vehi-
cle will become extremely unstable during br aking, and the ABS system may fail, which
could cause an accident resultin g in death or serious injury.■
When the electric power steering system warning light comes on
When the light comes on yellow, the assist to the power steering is restricted. When the
light comes on red, the assist to the power steering is lost and ha ndling operations of
the steering wheel become extremely heavy. When steering wheel operations are
heavier than usual, grip the steering wheel firmly and operate it using more force than
usual. ■
If the tire pressure warning light comes on
Be sure to observe the following precaution s. Failure to do so could cause a loss of
vehicle control and result in death or serious injury.●
Stop your vehicle in a safe place as soon as possible. Adjust the tire inflation pressure
immediately. ●
If the tire pressure warning light comes on even after tire inflation pressure adjust-
ment, it is probable that you have a flat tire . Check the tires. If a tire is flat, change it
with the spare tire and have the flat tire repaired by the nearest Lexus dealer. ●
Avoid abrupt maneuvering and braking. If the vehicle tires deteriorate, you could lose
control of the steering wheel or the brakes. ■
If a blowout or sudden air leakage should occur
The tire pressure warning system may not activate immediately.

666 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85UWARNING ■
Maintenance of the tires
Each tire, including the spare (if provided), should be checked monthly when cold and
inflated to the inflation pressure recomm ended by the vehicle manufacturer on the
vehicle placard or tire inflation pressure label (tire and load information label). (If your
vehicle has tires of a different size than the size indicated on the vehicle placard or tire
inflation pressure label [tire and load in formation label], you should determine the
proper tire inflation pressure for those tires.)
As an added safety feature, your vehicle ha s been equipped with a tire pressure moni-
toring system (TPMS-tire pressure warning system) that illuminates a low tire pressure
telltale (tire pressure warning light) when on e or more of your tires is significantly
under-inflated. Accordingly, when the low ti re pressure telltale (tire pressure warning
light) illuminates, you should st op and check your tires as soon as possible, and inflate
them to the proper pressure. Driving on a si gnificantly under-inflat ed tire causes the
tire to overheat and can lead to tire failure . Under-inflation also reduces fuel efficiency
and tire tread life, and may affect the vehicle’s handling and stopping ability.
Please note that the TPMS (tire pressure wa rning system) is not a substitute for proper
tire maintenance, and it is th e driver’s responsibility to ma intain correct tire pressure,
even if under-inflation has not reached the le vel to trigger illumina tion of the TPMS low
tire pressure telltale (tir e pressure warning light).
Your vehicle has also been equipped with a TPMS (tire pressure warning system) mal-
function indicator to indicate when the system is not operating properly. The TPMS
(tire pressure warning system) malfunction indi cator is combined with the low tire pres-
sure telltale (tire pressure warning light). When the system detects a malfunction, the
telltale will flash for approximately one mi nute and then remain continuously illumi-
nated. This sequence will cont inue upon subsequent vehicl e start-ups as long as the
malfunction exists. When the malfunction in dicator is illuminated, the system may not
be able to detect or signal low tire pressure as intended.
TPMS (tire pressure warning system) malfun ctions may occur for a variety of reasons,
including the installation of replacement or alternate tires or wheels on the vehicle that
prevent the TPMS (tire pressure warning system) from functioning properly. Always
check the TPMS (tire pressure warning system) malfunction telltale after replacing one
or more tires or wheels on your vehicle to ensure that the replacement or alternate
tires and wheels allow the TPMS (tire pressu re warning system) to continue to function
properly.
NOTICE ■
To ensure the tire pressure warning system operates properly
Do not install tires with different specificatio ns or makers, as the tire pressure warning
system may not operate properly.

6678-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UThe warning lights and warning buzzers operate as follows depending on the
content of the message. If a message indicates the need for inspection by a
dealer, have the vehicle inspected by your Lexus dealer immediately.If a warning message is displayed The multi-information display shows warn ings of system malfunctions, incor-
rectly performed operations, and messag es that indicate a need for mainte-
nance. When a message is shown, perform the correction procedure
appropriate to the message. 
Except F SPORT models 
F SPORT models
Master warning light The master warning light also comes on or flashes in order to indicate that a message
is currently being displayed on the multi-information display.
Multi-information display
If any of the warning messages are sh own again after the appropriate actions
have been performed, contact your Lexus dealer.
Messages and warnings 1
2
System
warning
light Warning buzzer
* Warning
Comes
on ⎯ Sounds Indicates an important situation, such
as when a system related to driving is
malfunctioning or that danger may
result if the correction procedure is not
performed
⎯ Comes on
or flashes Sounds Indicates an important situation, such
as when the systems shown on the
multi-information display may be mal-
functioning