warning light LEXUS RC300H 2017 Workshop Manual

4867-3. Do-it-yourself maintenance
RC300h_EE(OM24740E)
Your vehicle is equipped with a tire pressure warning system that uses tire pres-
sure warning valves and transmitters to detect low tire inflation pressure before
serious problems arise.
●If the tire pressure drops below a predetermined level, the driver is warned by
a screen display and a warning light. ( P. 539, 552)
●The tire pressure detected by the
tire pressure warning system can be
displayed on the multi-information
display. ( P. 121)
The illustration used is intended as an example, and may differ from the image
that is actually displayed on the multi- information display.
◆Installing tire pressure warning valves and transmitters
When replacing tires or wheels, tire pressure warning valves and transmitters
must also be installed.
When new tire pressure warning valves and transmitters are installed, new ID
codes must be registered in the tire pressure warning computer and the tire
pressure warning system must be initialized. Have tire pressure warning valve
and transmitter ID codes registered by any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional. ( P. 487)
Tire pressure warning system

4877-3. Do-it-yourself maintenance
7
Maintenance and care
RC300h_EE(OM24740E)
◆Initializing the tire pressure warning system
■The tire pressure warning system must be initialized in the following circum-
stances:
●When rotating the tires.
●When the tire inflation pressure is changed such as when changing
traveling speed.
●When changing the tire size.
When the tire pressure warning system is initialized, the current tire inflation
pressure is set as the benchmark pressure.
■How to initialize the tire pressure warning system
Park the vehicle in a safe place and turn the power switch off.
Initialization cannot be perfor med while the vehicle is moving.
Adjust the tire inflation pressure to the specified cold tire inflation pressure
level. ( P. 604)
Make sure to adjust the tire pressure to the specified cold tire inflation pressure
level. The tire pressure warning system will operate based on this pressure level.
Turn the power switch to ON mode.
Press and hold the tire pressure
warning reset switch until the tire
pressure warning light blinks
slowly 3 times.
Wait for a few minutes with the power switch in ON mode and then turn
the power switch off.
◆Registering ID codes
The tire pressure warning valve and transmitter is equipped with a unique ID
code. When replacing a tire pressure wa rning valve and transmitter, it is nec-
essary to register the ID code. Have the ID code registered by any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional.
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2
3
4
5

4887-3. Do-it-yourself maintenance
RC300h_EE(OM24740E)
■When to replace your vehicle’s tires
Tires should be replaced if:
●The treadwear indicators are showing on a tire.
●You have tire damage such as cuts, splits, cracks deep enough to expose the fabric, and
bulges indicating internal damage
●A tire goes flat repeatedly or cannot be prop erly repaired due to the size or location of a cut or other damage
If you are not sure, consult any authorized Lexus dealer or repairer, or another duly qual- ified and equipped professional.
■Replacing tires and wheels
If the ID code of the tire pressure warning valve and transmitter is not registered, the tire pressure warning system will not work proper ly. After driving for about 10 minutes, the tire pressure warning light blinks for 1 minu te and stays on to indicate a system malfunc-
tion.
■Tire life
Any tire over 6 years old must be checked by a qualified technician even if it has seldom
or never been used or damage is not obvious.
■Routine tire inflation pressure checks
The tire pressure warning system does not re place routine tire inflation pressure checks.
Make sure to check tire inflation pressure as part of your routine of daily vehicle checks.
■When rotating the tires
Make sure that the power switch is off. If the tires are rotated while the power switch is in
ON mode, the tire position information will not be updated. If this accidentally occurs, either turn the power switch to off and then to ON mode, orinitialize the system after checking that the tire pressure is properly adjusted.
■Low profile tires
Generally, low profile tires will wear more ra pidly and tire grip performance will be reduced on snowy and/or icy roads when comp ared to standard tires. Be sure to use
snow tires or tire chains on snowy and/or icy roads and drive carefully at a speed appro- priate for road and weather conditions.
■If the tread on snow tires wears down below 4 mm (0.16 in.)
The effectiveness of the tires as snow tires is lost.

4907-3. Do-it-yourself maintenance
RC300h_EE(OM24740E)
■When initialization of the tire pressure warning system has failed
Initialization can be co mpleted in a few minutes. However, in the following cases, the set- tings have not been recorded and the syst em will not operate properly. If repeated
attempts to record tire inflation pressure settings are unsuccessful, have the vehicle inspected by any authorized Lexus dealer or repairer, or another duly qualified and equipped professional.
●When operating the tire pressure warning re set switch, the tire pressure warning light does not blink 3 times.
●After carrying out the initializat ion procedure, the tire pressure warning light blinks for 1
minute then stays on after driving for 20 minutes.
■Registering ID codes
The ID codes of the tire pressure warning valve and transmitters for two sets of wheels
can be registered.
It is not necessary to register the ID codes wh en replacing normal tires with snow tires, if the ID codes for the wheels of both normal tires and snow tires are registered before-
hand.
For information about changing ID codes, as k any authorized Lexus dealer or repairer, or another duly qualified and equipped professional.

4977-3. Do-it-yourself maintenance
7
Maintenance and care
RC300h_EE(OM24740E)
WARNING
■When inspecting or replacing tires
Observe the following precautions to prevent accidents. Failure to do so may cause damage to parts of the drivetrain as well as dangerous han-
dling characteristics, which may lead to an acc ident resulting in death or serious injury.
●Do not mix tires of different makes, models or tread patterns. Also, do not mix tires of remarkably different treadwear.
●Do not use tire sizes other th an those recommended by Lexus.
●Do not mix differently constructed tires (radial, bias-belted or bias-ply tires).
●Do not mix summer, all season and snow tires.
●Do not use tires that have been used on another vehicle. Do not use tires if you do not know how they were used previously.
●Do not tow anything if a tire that has been repaired using the emergency tire puncture
repair kit is installed. The load on the tire may cause unexpected damage to the tire.
■When initializing the tire pressure warning system
Do not operate the tire pressure warning re set switch without first adjusting the tire
inflation pressure to the specified level. Ot herwise, the tire pressure warning light may not come on even if the tire inflation pressu re is low, or it may come on when the tire inflation pressure is actually normal.
■Caution regarding interference with electronic devices
●Users of any electrical medical device other than implantable cardiac pacemakers,
cardiac resynchronization therapy-pacemakers or implantable cardioverter defibrillators should consult the manufacturer of the device for information about itsoperation under the influence of radio waves.
Radio waves could have unexpected effects on the operation of such medical devices.
●People with implantable cardiac pacemakers,
cardiac resynchronization therapy-pacemak- ers or implantable cardioverter defibrillatorsshould not come within 450 mm (17.7 in.) of
the tire pressure warning system initiators. The radio waves may affect the operation ofsuch devices.

5027-3. Do-it-yourself maintenance
RC300h_EE(OM24740E)
Raise the vehicle until the tire is
slightly raised off the ground.
Remove all the wheel nuts and the
tire.
When resting the tire on the ground,
place the tire so that the wheel design faces up to avoid scratching the wheelsurface.
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5
WARNING
■Replacing a flat tire
●Do not touch the disc wheels or the area around the brakes immediately after thevehicle has been driven.
After the vehicle has been driven the disc wheels and the area around the brakes will be extremely hot. Touching these areas wi th hands, feet or other body parts while changing a tire, etc. may result in burns.
●Failure to follow these precautions could cause the wheel nuts to loosen and the tireto fall off, resulting in death or serious injury.
• Never use oil or grease on the wheel bolts or wheel nuts.
Oil and grease may cause the wheel nuts to be excessively tightened, leading to bolt or disc wheel damage. In addition, the oil or grease can cause the wheel nuts to loosen and the wheel may fall off, causing a serious accident. Remove any oil or
grease from the wheel bolts or wheel nuts. • Have the wheel nuts tightened with a torque wrench to 103 N•m (10.5 kgf•m,76 ft•lbf) as soon as possible after changing wheels.
• Do not attach a heavily damaged wheel or nament, as it may fly off the wheel while the vehicle is moving.• When installing a tire, only use wheel nuts that have been specifically designed for
that wheel. • If there are any cracks or deformations in the bolt screws, nut threads or bolt holesof the wheel, have the vehicle inspected by any authorized Lexus dealer or
repairer, or another duly qualif ied and equipped professional.

5177-3. Do-it-yourself maintenance
7
Maintenance and care
RC300h_EE(OM24740E)
■After a fuse is replaced
●If the lights do not turn on even after the fuse has been replaced, a bulb may need replacement. ( P. 518)
●If the replaced fuse blows again, have the vehicle inspected by any authorized Lexus
dealer or repairer, or another duly qualified and equipped professional.
■If there is an overload in a circuit
The fuses are designed to blow, protecting the wiring harness from damage.
■When replacing light bulbs
Lexus recommends that you us e genuine Lexus products designed for this vehicle. Because certain bulbs are connected to circuits designed to prevent overload, non-gen-
uine parts or parts not designed for this vehicle may be unusable.
WARNING
■To prevent system breakdowns and vehicle fire
Observe the following precautions. Failure to do so may cause damage to the vehicle, and possibly a fire or injury.
●Never use a fuse of a higher amperage rating than that indicated, or use any otherobject in place of a fuse.
●Always use a genuine Lexus fuse or equivalent.
Never replace a fuse with a wire, even as a temporary fix.
●Do not modify the fuses or fuse boxes.
■Fuse box near the power control unit
Never check or replace the fuses as there ar e high voltage parts and wiring near the fuse box.Doing so may cause electric shock, re sulting in death or serious injury.
NOTICE
■Before replacing fuses
Have the cause of electrical overload determined and repaired by any authorized Lexus dealer or repairer, or another duly qualified and equipped professional as soon as possible.

5267-3. Do-it-yourself maintenance
RC300h_EE(OM24740E)
WARNING
■Replacing light bulbs
●Turn off the lights. Do not attempt to replace 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 bulb 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 scratched 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 wate r entering the headlight unit. This may damage the head- lights or cause condensation to build up on the lens.
■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.

527
8When trouble arises
RC300h_EE(OM24740E)
8-1. Essential information
Emergency flashers ..................528
If your vehicle has
to be stopped
in an emergency...................... 529
8-2. Steps to take
in an emergency
If your vehicle needs
to be towed................................530
If you think something
is wrong....................................... 536
If a warning light turns
on or a warning buzzer
sounds.......................................... 537
If a warning message
is displayed ................................ 542
If you have a flat tire .................. 563
If the hybrid system will
not start ....................................... 576
If the electronic key does
not operate properly ............. 578
If the 12-volt battery is
discharged .................................582
If your vehicle overheats ......... 587
If the vehicle becomes
stuck ............................................. 592

5378-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
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, but 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 any authorized Lexus dealer or repairer, or
another duly qualified an d equipped professional.
Warning light and warning buzzer list
Warning lightWarning light/Details/Actions
Brake system warning light (warning buzzer) Indicates that:
• The brake fluid level is low; or • The brake system is malfunctioningThis light also comes on when the parking brake is not released. If
the light turns off after the parking brake is fully released the system is operating normally. Immediately stop the vehicle in a safe place and contact any
authorized Lexus dealer or repairer, or another duly qualified and equipped professional. Continuing to drive the vehicle maybe dangerous.
Brake system warning lightIndicates a malfunction in:• The regenerative braking system; or
• The electronically controlled brake system  Have the vehicle inspected by any authorized Lexus dealer or repairer, or another duly qualified and equipped professional
immediately.
Charging system warning light Indicates a malfunction in the vehicle’s charging system Immediately stop the vehicle in a safe place and contact any
authorized Lexus dealer or repairer, or another duly qualified and equipped professional.
Malfunction indicator lampIndicates a malfunction in:
• The hybrid system; • The emission control system (if equipped);• The electronic engine control system; or
• The electronic throttle control system  Have the vehicle inspected by any authorized Lexus dealer or repairer, or another duly qualified and equipped professional
immediately.