warning LEXUS RX450h 2015 Repair Manual

5
When trouble arises
7375-2. Steps to take in an emergency
* 1
: Open door warning buzzer:
The open door warning buzzer sounds to alert one or more of the doors is not
fully closed (with the vehicle having reached a speed of 3 mph [5 km/h]).
(  P. 74 8 )
* 2
: Driver's and front passenger’s seat belt buzzer:
The driver’s and front passenger’s seat belt buzzer sounds to alert the driver and
front passenger that his or her seat belt is not fastened. The buzzer sounds inter-
mittently for 10 seconds after the vehicle reaches a speed of 12 mph (20 km/h).
Then, if the seat belt is still unfastened , the buzzer will sound in a different tone
for 20 more seconds. Tire pressure warning light
When the light comes on:
Low tire inflation pressure
such as
• Natural causes (  P. 7 3 9 )
• Flat tire (  P. 76 4 ) Adjust the tire inflation pres-
sure (including the full-size
spare tire) to the specified
level.
The light will turn off after a
few minutes. In case the light
does not turn off even if the
tire inflation pressure is
adjusted, have the system
checked by your Lexus
dealer.
When the light comes on after
blinking for 1 minute:
Malfunction in the tire pres-
sure warning system
(  P. 74 0 ) Have the system checked by
your Lexus dealer.Warning light Warning light/Details Correction procedure

7385-2. Steps to take in an emergency
■
If the malfunction indicator lamp comes on while driving
First check the following: ●
Is the fuel tank empty?
If it is, fill the fuel tank immediately.●
Is the fuel tank cap loose?
If it is, tighten it securely.
The lamp will go off after several driving trips.
If the light does not go off even after several trips, contact your Lexus dealer as soon
as possible.■
SRS warning light
This warning light system monitors the airb ag sensor assembly, front airbag sensors,
side and curtain shield airbag sensors, curtain shield and rear side airbag sensors,
door sensors, driver's seat position sensor, driver's seat belt buckle switch, front
passenger occupant classification system (ECU and sensors), “AIR BAG ON” indi-
cator light, “AIR BAG OFF” in dicator light, front pass enger's seat belt buckle
switch, seat belt pretensioner assemblies, inflators, interconnecting wiring and
power sources. (  P. 1 3 2 )■
Front passenger detection sensor, passen ger 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 passenger is not sitting in the seat.●
If a cushion is placed on the seat, the sensor may not detect a passenger, and the
warning light may not operate properly.■
Electric power steering system warning light (warning buzzer)
When the 12-volt battery charge becomes insufficient or the voltage temporarily
drops, the electric power steering system warning light may come on and the warn-
ing buzzer may sound.
■
When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Pushing the tire
pressure warning reset switch will not turn off the tire pressure warning light.

5
When trouble arises
7395-2. Steps to take in an emergency
■
The tire pressure warning light may 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 chan ges caused by temperature. In this case,
adjusting the tire inflation pressure will turn off the warning light (after a few min-
utes).■
When a tire is replaced with a spare tire
Vehicles with a compact spare tire
The compact spare tire is not equipped with a tire pressure warning valve and trans-
mitter. 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 inflatio n pressure. The tire pressure warning light
will go off after a few minutes.
Vehicles with a full-size spare tire
The spare tire is also equipped with the tire pressure warning valve and transmitter.
The tire pressure warning light will turn on if the tire inflation pressure of the spare
tire is low. If a tire goes flat, even though the flat tire is replaced with the spare tire,
the tire pressure warning light does not turn off. Replace the spare tire with the
repaired tire and adjust to the proper tire inflation pressure. The tire pressure warn-
ing light will turn off after a few minutes.■
If the tire pressure warning system is not functioning
The tire pressure warning system will be disabled in the following conditions:
(When the condition becomes normal, the system will work properly.) ●
If tires not equipped with tire pressure warning valves and transmitters are used●
If the ID code on the tire pressure warning valves and transmitters is not regis-
tered in the tire pressure warning computer●
If the tire inflation pressure is 73 psi (500 kPa, 5.1 kgf/cm 2
or bar) or higher
The tire pressure warning system may be disabled in the following conditions:
(When the condition becomes normal, the system will work properly.)
●
If electronic devices or facilities using similar radio wave frequencies are nearby
●
If a radio set at similar frequencies is in use in the vehicle
●
If a window tint that affects the radio wave signals is installed
●
If there is a lot of snow or ice on the vehicle, in particular around the wheels or
wheel housings

7405-2. Steps to take in an emergency
●
If non-genuine Lexus wheels are used (Even if you use Lexus wheels, the tire
pressure warning system may not work properly with some types of tires.)●
If tire chains are used●
Vehicles with a full-size spare tire: If the spare tire is in a location subject to poor
radio wave signal reception●
Vehicles with a full-size spare tire: If a large metallic object which can interfere
with signal reception is pu t in the luggage compartment■
If the tire pressure warning light freque ntly comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute
when the “POWER” switch is turned to ON mode, have it checked by your Lexus
dealer.■
Customization
The vehicle speed linked seat belt reminder buzzer can be disabled.
(Customizable features  P. 825)
CAUTION■
When the electric power steering system warning light comes on
The steering wheel may become extremely heavy.
If the steering wheel becomes heavier than usual when operating, hold firmly and
operate using more force than usual.■
If the tire pressure warning light comes on
Be sure to observe the following precautions. Failure to do so could cause 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 pres-
sure 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.

5
When trouble arises
7415-2. Steps to take in an emergency
CAUTION■
Maintenance of the tires
Each tire, including the spare (if provided ), should be checked monthly when cold
and inflated to the inflation pressure re commended 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 [t ire and load information label], you should
determine the proper tire inflation pressure for those tires.)
As an added safety feature, your vehicl e has been equipped with a tire pressure
monitoring system (TPMS-tire pressure wa rning system) that illuminates a low tire
pressure telltale (tire pressure warning light) when one or more of your tires is sig-
nificantly under-inflated. Accordingly, when the low tire pressure telltale (tire pres-
sure warning light) illuminates, you should stop and check your tires as soon as
possible, and inflate them to the proper pressure. Driving on a significantly under-
inflated tire causes the tire to overheat an d 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 warning system) is not a substitute for
proper tire maintenance, and it is the driver's responsibility to maintain correct tire
pressure, even if under-inflation has not reached the level to trigger illumination of
the TPMS low tire pressure telltale (tire pressure warning light).
Your vehicle has also been equipped with a TPMS (tire pressure warning system)
malfunction indicator to indicate when th e system is not operating properly. The
TPMS (tire pressure warning system) malf unction indicator is combined with the
low tire pressure telltale (tire pressure warning light). When the system detects a
malfunction, the telltale will flash for approximately one minute and then remain
continuously illuminated. This sequence will continue upon subsequent vehicle
start-ups as long as the malfunction exists . When the malfunction indicator is illumi-
nated, the system may not be able to detect or signal low tire pressure as intended.
TPMS (tire pressure warning system) malfunctions may occur for a variety of rea-
sons, including the installation of replacem ent 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 tell-
tale 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 pressure warning
system) to continue to function properly.

7425-2. Steps to take in an emergency
NOTICE■
To ensure the tire pressure warning system operates properly
Do not install tires with different specificat ions or makers, as the tire pressure warn-
ing system may not operate properly.

5
When trouble arises
7435-2. Steps to take in an emergency
If a warning message is displayed
Stop the vehicle immediately. Continuing to drive the vehicle may be dangerous.
The following warning in dicates a possible problem in the brake system.
Immediately stop the vehi cle in a safe place and contact your Lexus
dealer.
Wa r n i n g m e s s a g e Details
(U.S.A.)

(Canada) Indicates the following:
• The brake fluid level is low; or,
• The brake system is malfunctioning.
A buzzer also sounds.
Indicates a malfunction in:
• The regenerative brake system; or,
• The electronically controlled brake system
A buzzer also sounds.If a warning is shown on the multi-information display, stay calm and per-
form the following actions:
Master warning light The master warning light also
comes on or flashes in order to
indicate that a message is cur-
rently being displayed on the
multi-information display.
Multi-information display
If any of the warning lights comes on again after the following actions
have been performed, contact your Lexus dealer.

7445-2. Steps to take in an emergency
Stop the vehicle immediately.
A buzzer sounds and a warning message is shown on the multi-informa-
tion display. The following warning indicates the possibility of damage to
the vehicle that may lead to an acci dent. Immediately stop the vehicle in a
safe place and contact your Lexus dealer. Wa r n i n g m e s s a g e Details
(U.S.A.)
(Canada) Indicates abnormal engine oil pressure
The warning light may come on if the engine oil pres-
sure is too low.
Indicates a malfunction in the hybrid system

5
When trouble arises
7455-2. Steps to take in an emergency
Have the vehicle inspected by your Lexus dealer immediately.
A buzzer sounds and a warning message is shown on th e multi-informa-
tion display. Failure to investigate the cause of the fo llowing warnings may
lead to the system operating abnormally and possibly cause an accident.
Have the vehicle inspected by your Lexus dealer immediately. Wa r n i n g m e s s a g e Details
(AWD models) Indicates a malfunction in the AWD system
Indicates a malfunction in the steering lock system
(Flashes)
(If equipped) Indicates a malfunction in the LED headlight system
Indicates a malfunction in the brake lights system

7485-2. Steps to take in an emergency
Follow the correction procedures.
A buzzer sounds and a warning message is shown on the multi-informa-
tion display. After taking the spec ified steps to correct the suspected
problem, check that the warning message goes off. Wa r n i n g m e s s a g e Details Correction procedure
Indicates that one or
more of the doors is not
fully closed
The system also indi-
cates which doors are
not fully closed.
If the vehicle reaches a
speed of 3 mph
(5 km/h), a buzzer
sounds to indicate that
the door(s) are not yet
fully closed. Make sure that all the
doors are closed.
Indicates that the hood is
not fully closed
If the vehicle reaches a
speed of 3 mph
(5 km/h), a buzzer
sounds to indicate that
the hood is not yet fully
closed. Close the hood.