
5397-2. Steps to take in an emergency
7
When trouble arises
RX450h_U_OM0E013U
*: 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 unfastened, 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.
■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. 38)
■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 insufficient of 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.

5627-2. Steps to take in an emergency
RX450h_U_OM0E013U
One of the following may be the cause of the problem:
●The 12-volt battery may be discharged. (P. 568)
●One or both of the 12-volt battery terminals may be disconnected. ( P. 483)
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. 233, 245)
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
2
3
4

5677-2. Steps to take in an emergency
7
When trouble arises
RX450h_U_OM0E013U
■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. 506)
■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. 233)
■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. 610)
●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 power window or the moon roof or panoramic
moon roof.
3

5707-2. Steps to take in an emergency
RX450h_U_OM0E013U
Start 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 your 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 components when the vehicle is running at a low
speed for an extended period , such as in heavy traffic.
■Charging the 12-volt battery
The electricity stored in the 12-volt battery w ill discharge gradually even when the vehicle
is not in use, due to natural discharge and the draining effects of certain electrical appli-
ances. If the vehicle is left for a long time, the 12-volt battery may discharge, and the
hybrid system may be unable to start. (The 12-volt battery recharges automatically while
the hybrid system is operating.)
■When the 12-volt battery is removed or discharged
●In some cases, it may not be possible to un lock the doors using the smart access system
with push-button start when the 12-volt battery is discharged. Use the wireless remote
control or the mechanical key to lock or unlock the doors.
●The hybrid system may not start on the first attempt after the 12-volt battery has
recharged but will start normally after the second attempt. This is not a malfunction.
●The power switch mode is memorized by the vehicle. When the 12-volt battery is
reconnected, the system will retu rn to the mode it was in before the 12-volt battery was
discharged. Before disconnect ing the 12-volt battery, turn the power switch off.
If you are unsure what mode the power switch was in before the 12-volt battery dis-
charged, be especially careful when reconnecting the 12-volt battery.
●The power back door must be initialized. ( P. 150)
6
7
8
9
10
11

6048-1. Specifications
RX450h_U_OM0E013U
Intended outboard sidewall
(a)The sidewall that contai ns a whitewall, bears white
lettering, or bears manufacturer, brand, and/or
model name molding that is higher or deeper than
the same molding on the other sidewall of the tire, or
(b)The outward facing sidewa ll of an asymmetrical tire
that has a particular side that must always face out-
ward when mounted on a vehicle
Light truck (LT) tireA tire designated by its manufacturer as primarily
intended for use on lightweig ht trucks or multipurpose
passenger vehicles
Load ratingThe maximum load that a tire is rated to carry for a given
inflation pressure
Maximum load ratingThe load rating for a tire at the maximum permissible
inflation pressure for that tire
Maximum permissible infla-
tion pressureThe maximum cold inflation pr essure to which a tire may
be inflated
Measuring rimThe rim on which a tire is fitted for physical dimension
requirements
Open spliceAny parting at any junction of tread, sidewall, or inner-
liner that extends to cord material
Outer diameterThe overall diameter of an inflated new tire
Overall width
The linear distance between the exteriors of the side-
walls of an inflated tire, including elev ations due to label-
ing, decorations, or protective bands or ribs
Passenger car tireA tire intended for use on passenger cars, multipurpose
passenger vehicles, and trucks, that have a gross vehicle
weight rating (GVWR) of 10,000 lb. or less.
PlyA layer of rubber-coat ed parallel cords
Ply separationA parting of rubber compou nd between adjacent plies
Tire related termMeaning

6168-2. Customization
RX450h_U_OM0E013U
■Driving mode select switch ( P. 377)
*: If equipped
■Automatic air conditioning system ( P. 405)
■Seat heaters/seat ventilators ( P. 415, 416)
FunctionDefault settingCustomized setting
Powertrain control in customized
mode
*NormalPowerO—Eco
Chassis control in customized
mode*NormalSportO—
Air conditioning operation in
customized mode
*NormalEcoO—
12
FunctionDefault settingCustomized setting
A/C auto switch operationOnOffOO
Exhaust gas sensor sensitivityStandard-3 to 3OO
12
FunctionDefault settingCustomized setting
Driver’s seat temperature prefer-
ence in automatic modeStandard-2 (cooler) to 2
(warmer)OO
Front passenger’s seat tempera-
ture preference in automatic
modeStandard-2 (cooler) to 2 (warmer)OO
12

644Alphabetical index
RX450h_U_OM0E013U
DrivingBreak-in tips ........................................ 206
Correct posture.....................................30
Driving mode select switch .......... 377
Hybrid vehicle driving tips.............387
Procedures ...........................................204
Winter drive tips ................................ 390
Driving position memory..................... 174 Memory recall function..................... 177
Power easy access system .............174
Dynamic radar cruise control ......... 323
Dynamic radar cruise control with full-speed range .......................... 311
E-Four ....................................................... 382
ECB (Electronically Controlled Brake System) ..................................... 381
Eco drive mode ......................................377
EDR (Event data recorder) .................... 11
Electric motor Location ..................................................... 76
Specification ........................................ 584
Electric Power Steering (EPS) ........ 381 Warning light .......................................537
Electronic key ..........................................132 Battery-saving function .................... 159
If the electronic key does not operate properly............................ 564
Replacing the battery ...................... 506 Electronically Controlled
Brake System (ECB) .........................381
Emergency flashers ............................ 528
Emergency, in case of If a warning buzzer sounds ..........536
If a warning light turns on ..............536
If a warning message is displayed ............................................ 543
If the 12-volt battery is discharged........................................ 568
If the electronic key does not operate properly ............................564
If the hybrid system will not start .................................................561
If you have a flat tire ..........................549
If you lose your keys................ 133, 135
If you think something is wrong...................................................535
If your vehicle becomes stuck...................................................... 578
If your vehicle has to be stopped in an
emergency ........................................ 529
If your vehicle needs to be towed ...................................................530
If your vehicle overheats ................ 574
Energy monitor ....................................... 124
E

645Alphabetical index
RX450h_U_OM0E013U
EngineACCESSORY mode...................... 233
Compartment......................................475
Engine switch ....................................... 232
Hood ........................................................ 473
How to start the hybrid system .................................................. 232
Identification number ...................... 583
If your vehicle has to be stopped in an emergency ..........529
Ignition switch (power switch) .... 232
Overheating .........................................574
Power switch........................................ 232
Engine coolant Capacity ................................................ 587
Checking................................................ 479
Preparing and checking before winter ................................... 390
Engine coolant temperature gauge .........................................................97
Engine oil Capacity ................................................ 585
Checking................................................ 476
Preparing and checking before winter ................................... 390
Engine oil maintenance data ........... 478
Engine switch ......................................... 232
Enhanced VSC ...................................... 381
EPS (Electronic Power Steering) ......... 381 Warning light .......................................537
EV drive mode....................................... 237
EV indicator ............................................... 78
Event data recorder (EDR) .................... 11 Flat tire ...................................................... 549
Floor mats................................................... 28
Fluid
Brake....................................................... 588
Transmission ....................................... 588
Washer ................................................... 482
Fog lights Replacing light bulbs .........................513
Switch ...................................................... 259
Front passenger footwell hooks.......................................................442
Front passenger occupant classification system ............................. 51
Front passenger’s seat belt reminder light ..................................... 538
Front seat heaters .................................. 415
Front seats ................................................. 164 Adjustment..............................................164
Cleaning................................................. 462
Correct driving posture .................... 30
Driving position memory................. 174
Head restraints ..................................... 179
Power easy access system ............. 174
Seat heaters ............................................415
Seat position memory ....................... 174
Front side marker lights Light switch............................................. 251
Replacing light bulbs .........................513
Wattage ................................................ 590F