2021 LEXUS RX350 coolant temperature

4017-2. Steps to take in an emergency
7
When trouble arises
Fluid leaks under the vehicle
(Water dripping from the air condi-
tioning after use is normal.)
 Flat-looking tires or uneven tire
wear
 Engine coolant temperature gauge
needle continually points higher
than normal
 Changes in exhaust sound
 Excessive tire squeal when corner-
ing
 Strange noises related to the sus-
pension system
 Pinging or other noises related to
the engine
 Engine missing, stumbling or run-
ning roughly
 Appreciable loss of power
 Vehicle pulls heavily to one side
when braking 
Vehicle pulls heavily to one side
when driving on a level road
 Loss of brake effectiveness, spongy
feeling, pedal almost touches the
floor
If you think something is
wrong
If you notice any of the following
symptoms, your vehicle probably
needs adjustment or repair. Con-
tact your Lexus dealer as soon as
possible.
Visible symptoms
Audible symptoms
Operational symptoms

4037-2. Steps to take in an emergency
7
When trouble arises
■Brake system warning light
■Brake system warning light
■High coolant temperature warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
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, bu t 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 your Lexus dealer.
Actions to the warning lights or warning buzzers
Warning lightDetails/Actions
(U.S.A.)
or
(red)
(Canada)
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.
Warning lightDetails/Actions
(yellow)
Indicates a malfunction in the electric parking brake
 Have the vehicle inspected by your Lexus dealer immediately.
Warning lightDetails/Actions
Indicates that the engine coolant temperature is too high
Immediately stop the vehicle in a safe place.
Handling method ( P.437)

4157-2. Steps to take in an emergency
7
When trouble arises
■If “Radar Cruise Control Unavailable” is
displayed
The dynamic radar cruise control with
full-speed range system cannot be used
temporarily. Use the system when it
becomes available again.
■If a message that indicates the malfunc-
tion of front camera is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.207, 408)
●PCS (Pre-Collision system)
●LTA (Lane Tracing Assist)
●Automatic High Beam
●RSA (Road Sign Assist) (if equipped)
●Dynamic radar cruise control with
full-speed range
■If “Check Fuel Cap” is displayed (if
equipped)
The fuel tank cap is no t properly installed.
Correctly install the fuel tank cap.
■If “Maintenance Required Soon” is dis-
played (U.S.A. only)
Indicates that all maintenance according to
the driven distance on the maintenance
schedule
* should be performed soon.
Comes on approximately 4500 miles
(7200 km) after the message has been
reset. If necessary, perform maintenance.
Please reset the message after the mainte-
nance is performed. ( P.350)
*: Refer to the separa te “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the maintenance interval
applicable to your vehicle.
■If “Maintenance Required Visit Your
Dealer” is displayed (U.S.A. only)
Indicates that all maintenance is required to
correspond to the driven distance on the
maintenance schedule
*.
Comes on approximately 5000 miles
(8000 km) after the message has been
reset. (The indicator will not work properly
unless the message ha s been reset.) Per-
form the necessary maintenance. Please reset the message after the maintenance is
performed. (
P.350)
*: Refer to the separate “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the main tenance interval
applicable to your vehicle.
■If “Oil Maintenance Required Soon” is
displayed
Indicates that the engine oil should be
scheduled to be changed.
Check the engine oil an d change it if neces-
sary. After changing th e engine oil, make
sure to reset the message. ( P.361)
■If “Oil Maintenance Required” is dis-
played
Indicates that the engine oil should be
changed.
Check and change the en gine oil, and oil fil-
ter by your Lexus dealer. After changing the
engine oil, make sure to reset the message.
(  P.361)
■If a message that indicates the need for
visiting your Lexus dealer is displayed
The system or part shown on the
multi-information display is malfunctioning.
Have the vehicle inspected by your Lexus
dealer immediately.
■If a message that indicates the need for
referring to Owner’ s Manual is dis-
played
●“Engine Coolant Temp High” is shown on
the multi-information display, follow the
instructions. ( P.437)
●“Transmission Fluid Temp High” is shown
on the multi-informatio n display, the auto-
matic transmission fluid temperature may
be too high. Immediately stop the vehicle
in a safe place, shif t the shift lever to P
with the engine running and wait until the
message is cleared. If the message is not
cleared, contact your Lexus dealer.
●If the following mess age is shown on the
multi-information display, it may indicate
a malfunction. Have the vehicle inspected
by your Lexus dealer immediately.
• “Access System with Elec. Key Malfunc- tion”

4377-2. Steps to take in an emergency
7
When trouble arises
1Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the engine.
2 If you see steam:
Carefully lift the hood after the
steam subsides.
If you do not see steam:
Carefully lift the hood.
3 After the engine has cooled down
sufficiently, inspect the hoses and radiator core (radiator) for any
leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4
The coolant level is satisfactory if it
is between the “FULL” and “LOW”
lines on the reservoir.
Reservoir
“FULL” line
“LOW” line
Radiator cap
5 Add coolant if necessary.
Water can be used in an emergency if
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
The needle of the engine coolant
temperature gauge ( P.77)
enters the red zone, or a loss of
engine power is experienced.
(For example, the vehicle speed
does not increase.)
 “Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” is shown on the
multi-information display.
 Steam comes out from under the
hood.
Correction procedures
A
B
A
B
C
D

4387-2. Steps to take in an emergency
coolant is unavailable.
6Start the engine and turn the air
conditioning system on to check
that the radiator cooling fans oper-
ate and to check for coolant leaks
from the radiator or hoses.
The fans operate when the air conditioning
system is turned on immediately after a
cold start. Confirm that the fans are oper-
ating by checking the fan sound and air
flow. If it is difficult to check these, turn the
air conditioning system on and off repeat-
edly.
(The fans may not oper ate in freezing tem-
peratures.)
7 If the fans are not operating:
Stop the engine immediately and
contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the
nearest Lexus dealer.
8 Check if “Engine Coolant Temp
High Stop in a Safe Place See
Owner's Manual” is shown on the
multi-information display.
If the message does not disappear:
Stop the engine and contact your Lexus
dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
WARNING
■When inspecting under the hood of
your vehicle
Observe the following precautions.
Failure to do so may result in serious
injury such as burns.
●If steam is seen coming from under the
hood, do not open the hood until the
steam has subsided. The engine com-
partment may be very hot.
●Keep hands and clothing (especially a
tie, a scarf or a muffler) away from the
fans and belts.
Failure to do so may cause the hands
or clothing to be caught, resulting in
serious injury.
●Do not loosen the radiator cap and the
coolant reservoir cap while the engine
and radiator are hot.
High temperature steam or coolant
could spray out.
NOTICE
■When adding engine coolant
Add coolant slowly after the engine has
cooled down sufficiently. Adding cool
coolant to a hot engine too quickly can
cause damage to the engine.
■To prevent damage to the cooling sys-
tem
Observe the following precautions:
●Avoid contaminating the coolant with
foreign matter (such as sand or dust,
etc.).
●Do not use any coolant additive.

496Alphabetical Index
If the vehicle is trapped in rising water.........................................................................395
If you have a flat tire ....................................416
If you lose your keys.................................430
If you think something is wrong .......... 401
If your vehicle becomes stuck............. 439
If your vehicle has to be stopped in an
emergency ................................................ 394
If your vehicle needs to be towed ..... 397
If your vehicle overheats ........................ 437
Engine ACCESSORY mode ............................... 177
Compartment .............................................359
Engine switch................................................. 174
Fuel pump shut off system .................... 402
Hood................................................................ 357
How to start the engine............................ 174
Identification number ............................... 443
If the engine will not start ....................... 428
If your vehicle has to be stopped in an
emergency ................................................ 394
Ignition switch (engine switch) ............. 174
Overheating................................................. 437
Tachometer ...................................................... 77
Engine coolant Capacity ......................................................... 446
Checking .........................................................361
Preparing and checking before winter.........................................................................280
Engine coolant temperature gauge ........ 77
Engine immobilizer system ........................ 66
Engine oil Capacity ......................................................... 444
Checking .......................................................359
Preparing and checking before winter.........................................................................280
Warning light ...............................................404
Engine oil maintenance data ....................361
Engine switch .................................................. 174 Auto power off function ........................... 177
Changing the engine switch modes.. 177 If your vehicle has to be stopped in an
emergency .................................................394
EPS (Electric Power Steering) .............. 275 Warning light .............................................. 405
Event data recorder (E DR) ............................7
F
Flat tire
Tire pressure warning system ............. 367
Vehicles with a spare tire........................ 416
Floor mats .......................................................... 24
Fluid Automatic transmission .......................... 447
Brake ................................................................ 447
Washer ...........................................................364
Fog lights Switch................................................................ 194
Footwell light ................................................. 309
Front automatic air conditioning system .......................................................................... 292
Front fog lights Replacing light bulbs ............................... 385
Front passenger footwell hooks ............ 333
Front passenger occupant classification system .............................................................. 39
Front seats Adjustment ....................................................... 121
Cleaning ......................................................... 347
Correct driving posture ............................ 25
Driving position memory ........................ 133
Head restraints............................................. 136
Memory recall function............................ 135
Power easy access system .................... 133
Seat heaters ................................................. 306
Seat position memory .............................. 133
Seat ventilators ........................................... 306
Front side marker light Light switch ....................................................188
Replacing light bulbs ............................... 385
Front side marker lights Replacing light bulbs ............................... 385
Wattage ..........................................................449

504Alphabetical Index
V
Vanity lights.................................................... 333Wattage.......................................................... 449
Vanity mirrors ............................................... 333
VDIM (Vehicle Dynami cs Integrated Man-
agement)...................................................... 275
Vehicle data recording . ...................................6
Vehicle Dynamics Integrated Manage- ment (VDIM).............................................. 275
Vehicle identification number ................ 443
Vehicle Stability Control (VSC) ............274
Ventilators (seat ventilators)................... 306
VSC (Vehicle Stabilit y Control) ............274
W
Warning buzzers
Approach warning.................................... 233
Brake Override System .........................405
Door lock........................................................ 100
Downshifting .........................................181, 182
Drive-Start Control ..................................405
Electric power steering ..........................405
Hands off steering wheel warning (LTA)......................................................................... 223
High coolant temperature ....................403
Intuitive parking assist.................. 249, 407
Low engine oil pressure.........................404
LTA (Lane Tracing As sist)216, 219, 407
Open door......................................................102
Open window ...............................................145
PKSA (Parking Support Alert) ........... 242
PKSB (Parking Support Brake) ........ 408
Pre-collision braking..................................210
RCTA (Rear Cross Traffic Alert) ...... 407
Seat belt ..........................................................406
Warning lights............................................... 403 ABS ..................................................................405
Brake hold operated indicator ...........409
Brake Override System .........................405
Brake system ...............................................403
Charging system .......................................404 Drive-Start Control.................................. 405
Electric power steering.......................... 405
High coolant temperature.................... 403
Intuitive parking assist OFF indicator
..........................................................................407
Low engine oil pressure........................ 404
Low fuel level .............................................. 406
LTA indicator ...............................................407
Malfunction indicator lamp .................. 404
Master warning light................................ 409
Parking brake indicator ......................... 409
PKSB OFF indicator ............................... 408
Pre-collision system................................. 408
RCTA OFF indicator ...............................407
Seat belt reminder light.......................... 406
Slip indicator ................................................ 408
SRS ................................................................... 404
Tire pressure ................................................407
Warning messages ....................................... 412
Washer Adding.............................................................364
Preparing and checking before winter......................................................................... 280
Switch................................................................ 194
Washing and waxing.................................. 344
Weight Cargo capacity .................................. 159, 162
Load limits .......................................................162
Weight............................................................. 442
Wheels ............................................................. 374 Size ................................................................... 448
Window lock switch .....................................146
Windows Power windows ............................................144
Rear window defogger........................... 294
Washer ............................................................ 194
Windshield wiper de-icer ........................ 299
Windshield wiper inserts .......................... 378
Windshield wipers Position..............................................................197
Rain-sensing windshield wipers .......... 194
Replacing a windshield wiper insert.378