2018 LEXUS RX450h ECO mode

6097-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
Before recharging
When recharging, the 12-volt battery produc es hydrogen gas which is flammable and
explosive. Therefore, observe the following precautions before recharging: ●
If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the
ground cable. ●
Make sure the power switch on the charge r is off when connecting and disconnecting
the charger cables to the 12-volt battery. ■
After recharging/reconnecting the 12-volt battery ●
The hybrid system may not start. Follow the procedure below to initialize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the hybrid system. ●
Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the 12-volt battery. If this happens, use the
wireless remote control or the mechan ical key to lock/unlock the doors.●
Start the hybrid system with the power sw itch in ACCESSORY mo de. The hybrid sys-
tem may not start with the power switch turned off. However, the hybrid system will
operate normally from the second attempt.●
The power switch mode is recorded by the vehicle. If the 12-volt battery is reconnected,
the vehicle will return the power switch mode to the status it was in before the 12-volt
battery was disconnected. Make sure to turn off the power before disconnect the 12-
volt battery. Take extra care when connec ting the 12-volt battery if the power switch
mode prior to discharge is unknown.
If the system will not start even after multip le attempts at all methods above, contact your
Lexus dealer.
WARNING ■
Chemicals in the 12-volt battery
The 12-volt battery contains poisonous and corrosive sulfuric acid and may produce
hydrogen gas which is flammable and explosive. To reduce the risk of death or serious
injury, take the following precautions while working on or near the 12-volt battery:●
Do not cause sparks by touching the 12-volt battery terminals with tools. ●
Do not smoke or light a matc h near the 12-volt battery.●
Avoid contact with eyes, skin and clothes. ●
Never inhale or swallow electrolyte. ●
Wear protective safety glasses when working near the 12-volt battery. ●
Keep children away from the 12-volt battery. ■
Where to safely charge the 12-volt battery
Always charge the 12-volt battery in an open area. Do not charge the 12-volt battery in
a garage or closed room where th ere is insufficient ventilation.■
How to recharge the 12-volt battery
Only perform a slow charge (5 A or less). The 12-volt battery may explode if charged
at a quicker rate. 1
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6137-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85U■
How to initialize the tire pressure warning system
Park the vehicle in a safe place and turn the power switch off. Initialization cannot be performed while the vehicle is moving.
Adjust the tire inflation pressure to th e specified cold tire inflation pressure
level. ( → P. 717)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.
Select on the multi-information display. ( → P. 108)
Press or of the meter control sw itch, select the “Vehicle Settings”
screen and then press the .
Press or of the meter con-
trol switch, select the “TPMS”
screen and then press and hold
the
until the tire pressure
warning light blinks slowly 3
times. “- -” will be displayed for inflation
pressure of each tire on the multi-
information displa y while the tire
pressure warning system determines
the position of each tire.
When position of each tire is determined, the inflation pressure of each tire will be
displayed on the mult i-information display.
Drive the vehicle at approximately 25 mph (40 km/h) or more for approx-
imately 10 to 30 minutes until the inflat ion pressure of each tire is displayed
on the multi-information display. If tire inflation pressure becomes low before the inflation pressure is displayed, the
tire pressure warning light will come on.
Depending on the vehicle and driving co nditions, initialization may take up to
approximately 1 hour to complete.
◆ Registering ID codes
The tire pressure warning valve and tran smitter is equipped with a unique ID
code. When replacing a tire pressure warning valve and transmitter, it is nec-
essary to register the ID code. Have the ID code registered by your Lexus
dealer. 1
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6197-3. Do-it-yourself maintenance
7
Maintenance and care
RX450h_RX450hL _U_OM48F85UWARNING ■
When inspecting or replacing tires
Observe the following precautions to prevent accidents.
Failure to do so may cause damage to parts of the drive train as well as dangerous han-
dling characteristics, which may lead to an accident resu lting 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 than 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 be en used on another vehicle.
Do not use tires if you do not know how they were used previously. ●
Do not tow if your vehicle has a compact spare tire installed. ■
When initializing the tire pressure warning system
Do not initializing tire inflatio n pressure without first adjusting the tire inflation pressure
to the specified level. Otherwise, the tire pressure warning light may not come on even
if the tire inflation pressure is low, or it may come on when the tire inflation pressure is
actually normal.
NOTICE ■
Repairing or replacing tires, wheels, tire pressure warning valv es, transmitters and
tire valve caps ●
When removing or fitting the wheels, tires or the tire pressure warning valves and
transmitters, contact your Lexus dealer as the tire pressure warning valves and trans-
mitters may be damaged if not handled correctly. ●
Make sure to install the tire valve caps. If the tire valve caps ar e not installed, water
could enter the tire pressure warning valves and the tire pressure warning valves
could be bound. ●
When replacing tire valve caps, do not use tire valve caps other than those specified.
The cap may become stuck. ■
To avoid damage to the tire pressu re warning valves and transmitters
When a tire is repaired with liquid sealants, the tire pressure warning valve and trans-
mitter may not operate properly. If a liquid sealant is used, contact your Lexus dealer or
other qualified service shop as soon as possi ble. Make sure to replace the tire pressure
warning valve and transmitter when replacing the tire. ( → P. 612)■
Driving on rough roads
Take particular care when driving on roads with loose surfaces or potholes.
These conditions may cause lo sses in tire inflation pre ssure, reducing the cushioning
ability of the tires. In addition, driving on rough roads may cause damage to the tires
themselves, as well as the vehicle’s wheels and body. ■
If tire inflation pressure of ea ch tire becomes low while driving
Do not continue driving, or your tires and/or wheels may be ruined.

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
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6918-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UOne of the following may be the cause of the problem: ●
The 12-volt battery may be discharged. ( → P. 695)●
One or both of the 12-volt battery terminals may be disconnected. ( → P. 605)Contact your Lexus dealer if the problem cannot be repaired, or if repair procedures
are unknown.
When the hybrid system does not start, the following steps can be used as an
interim measure to start the hybrid system if the power switch is functioning nor-
mally.
Do not use this starting procedur e except in cases of emergency.
Turn the power switch to ON mode an d check that the parking brake is set.
( → P. 240, 253)
Shift the shift lever to P.
Turn the power switch to ACCESSORY mode.
Press and hold the power switch for ab out 15 seconds while depressing the
brake pedal firmly.
Even if the hybrid system can be starte d using the above steps, the system may
be malfunctioning. Have the vehicle inspected by your Lexus dealer.The interior lights and headlights do not turn on, or the horn does not
sound.
Emergency start function 1
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694 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
Stopping the hybrid system
Shift the shift lever to P, set the parking brake, and press the power switch as you normally
do when stopping the hybrid system. ■
Replacing the key battery
As the above procedure is a temporary measure, it is recommended that the electronic
key battery be replaced immediately when the battery is depleted. ( → P. 630)■
Changing power switch modes
Release the brake pedal and press the power switch in step above.
The hybrid system does not start and modes will be changed each time the switch is
pressed. ( → P. 240)■
When the electronic key does not work properly ●
Make sure that the smart access system wi th push-button start has not been deacti-
vated in the customization setting. If it is off, turn the function on.
(Customizable features → P. 740)●
Check if battery-saving mode is set. If it is set, cancel the function. ( → P. 160)
WARNING ■
When using the mechanical key and operating the power windows or the moon roof
or panoramic moon roof
Operate the power window or the moon roof or panoramic moon roof after checking
to make sure that there is no possibility of any passenger having an y of their body parts
caught in the window or the moon roof or panoramic moon roof.
Also, do not allow children to op erate the mechanical key. It is possible for children and
other passengers to get caught in the powe r window or the moon roof or panoramic
moon roof. 3

6978-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UStart the engine of the second vehicle. Increase the engine speed slightly and
maintain at that level for approximatel y 5 minutes to recharge the 12-volt bat-
tery of your vehicle.
Open and close any of the doors of yo ur vehicle with the power switch off.
Maintain the engine speed of the seco nd vehicle and start the hybrid system
of your vehicle by turning th e power switch to ON mode.
Make sure the “READY” indicator comes on. If the indicator light does not
come on, contact your Lexus dealer.
Once the hybrid system has started, remove the jumper cables in the exact
reverse order from which they were connected.
Close the exclusive jump starting termin al cover, and reinstall the fuse box
cover to its original position.
Once the hybrid system starts, have th e vehicle inspected at your Lexus dealer
as soon as possible. ■
Starting the hybrid system when the 12-volt battery is discharged
The hybrid system cannot be started by push-starting. ■
To prevent 12-volt battery discharge ●
Turn off the headlights and the audio system while the hybrid system is off. ●
Turn off any unnecessary electrical componen ts when the vehicle is running at a low
speed for an extended period , such as in heavy traffic.■
When removing the battery terminals
When the battery terminals are removed, the information stored in the ECU is cleared.
Before removing the battery termin als, contact your Lexus dealer.6
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