warning LEXUS RX450h 2018 Owners Manual

6497-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
LED lights
The headlight low beams, headlight high beams, front turn signal lights (vehicles with tri-
ple-beam headlights), parking lights and da ytime running lights, fog lights, cornering
lights (if equipped), front side marker lights (vehicles with triple-b eam headlights), side
turn signal lights, stop/tail lights, rear turn signal light (vehicles with triple-beam head-
lights), rear side marker lights, high mounted stoplight, license plate lights, and outer foot
lights consist of a number of LEDs. If any of the LEDs has burned out, take your vehicle to
your Lexus dealer to have the light replaced. ■
Condensation build-up on the inside of a lens
Temporary condensation build-up on the inside of the headlight lens does not indicate a
malfunction. Contact your Lexus dealer for mo re information in the following situations:●
Large drops of water have built up on the inside of a lens. ●
Water has built up inside a headlight. ■
When replacing light bulbs
→ P. 634
WARNING ■
To prevent injury
Before performing any light bulb replacement procedure, be sure to turn the power
switch off. Failure to do so may result in burns from hot components or a part of your
body may get caught on an operating co mponent, possibly causing serious injury.■
Replacing light bulbs ●
Turn off the lights. Do not attempt to replac e the bulb immediately after turning off the
lights.
The bulbs become very hot and may cause burns. ●
Do not touch the glass portion of the light bu lb with bare hands. When it is unavoid-
able to hold the glass portion, use and hold with a clean dry cloth to avoid getting
moisture and oils on the bulb.
Also, if the bulb is sc ratched or dropped, it may blow out or crack.●
Fully install light bulbs and any parts used to secure them. Failure to do so may result
in heat damage, fire, or water entering th e headlight unit. This may damage the head-
lights or cause condensation to build up on the lens.●
Do not attempt to repair or disassemble th e light bulbs, connector s, electric circuits
or component parts.
Doing so may result in death or se rious injury due to electric shock.■
To prevent damage or fire ●
Make sure bulbs are fully seated and locked. ●
Check the wattage of the bulb before installing to prevent heat damage.

651
8When trouble arises
RX450h_RX450hL _U_OM48F85U 8-1. Essential information
Emergency flashers .................. 652
If your vehicle has
to be stopped in
an emergency .......................... 653
8-2. Steps to take in
an emergency
If your vehicle needs
to be towed................................ 654
If you think something is
wrong ........................................... 659
If a warning light turns on
or a warning buzzer
sounds..........................................660
If a warning message is
displayed..................................... 667
If you have a flat tire .................. 673
If the hybrid system will
not start .......................................690
If the electronic key does
not operate properly ............. 692
If the 12-volt battery is
discharged ................................. 695
If your vehicle overheats ......... 702
If the vehicle becomes
stuck ............................................. 706

6538-1. Essential information
8
When trouble arises
RX450h_RX450hL _U_OM48F85USteadily step on the brake pedal with both feet and firmly depress it.Do not pump the brake pedal repeatedly as this will increase the effort required to
slow the vehicle.
Shift the shift lever to N. 
If the shift lever is shifted to N
After slowing down, stop the vehicle in a safe place by the road.
Stop the hybrid system. 
If the shift lever cannot be shifted to N
Keep depressing the brake pedal with both feet to reduce vehicle speed as
much as possible.
To stop the hybrid system, press and
hold the power switch for 2 consec-
utive seconds or more, or press it
briefly 3 times or more in succes-
sion.
Stop the vehicle in a safe place by the road.If your vehicle has to be stopped in an emergencyOnly in an emergency, such as if it becomes impossible to stop the vehicle in
the normal way, stop the vehicl e using the following procedure:1
2
3
4
3
Press and hold for 2 seconds or more,
or press briefly 3 times or more4
WARNING ■
If the hybrid system has to be turned off while driving
Power assist for the steering wheel will be lost, making the steering wheel heavier to
turn. Decelerate as much as possible before turning off the hybrid system.5

654
RX450h_RX450hL _U_OM48F85U8-2. Steps to take in an emergency
The following may indicate a problem wi th your hybrid transmission. Contact
your Lexus dealer or commercial towing service before towing. ●
The hybrid warning message shows on and the vehicle does not move. ●
The vehicle makes an abnormal sound.
Do not tow with a sling-type truck to
prevent body damage.If your vehicle needs to be towed If towing is necessary, we recommend having your vehicle towed by your
Lexus dealer or commercial towing se rvice, using a wheel-lift type truck or
flatbed truck.
Use a safety chain system for all towing, and abide by all state/provincial and
local laws.
If towing your vehicle with a wheel-lift type truck, use a towing dolly.
( → P. 655, 657)
Situations when it is necessary to contact dealers before towing
Towing with a sling-type truck

6578-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85U■
While towing
If the engine is not running, the power assist for the brakes and steering will not function,
marking steering and braking more difficult. ■
Wheel nut wrench
Wheel nut wrench is installe d in luggage compartment. ( → P. 674)
WARNING
Observe the following precautions.
Failure to do so may result in death or serious injury. ■
When towing the vehicle
■
While towing ●
When towing using cables or chains, avoid sudden starts, etc. which place excessive
stress on the towing eyelets, cables or chains. The towing eyelets, cables or chains
may become damaged, broken debris ma y hit people, and cause serious damage.●
Do not turn the power switch off.
There is a possibility that the steering wheel is locked and cannot be operated.■
Installing towing eyelets to the vehicle
Make sure that towing eyel ets are installed securely.
If not securely installed, towing ey elets may come loose during towing.Be sure to transport the vehicle with all four
wheels raised off the ground. If the vehicle is
towed with the tires contacting the ground, the
drivetrain or related parts may be damaged,
the vehicle may fly off th e truck, or electricity
generated by the operation of the motor may
cause a fire to occur depending on the nature
of the damage or malfunction.

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