2021 LEXUS RX350 check engine light

3816-3. Do-it-yourself maintenance
6
Maintenance and care
1Turn the engine switch off.
2 Open the fuse box cover.
Engine compartment
Push the tab in and lift the lid off.
Driver’s side instrument panel
Remove the lid.
3Remove the fuse with the pullout
tool. Only some fuses can be removed
using the pullout tool.
4 Check if the fuse is blown.
Normal fuse
Blown fuse
Replace the blown fuse with a new fuse of
an appropriate amperage rating. The
amperage rating can be found on the fuse
box lid.
Many types of fuse are used on this vehicle.
This illustration shows a common type of
fuse used on this vehicle.
■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.384)
●If the replaced fuse blows again, have the
vehicle inspected by your Lexus dealer.
■If there is an overload in a circuit
The fuses are designed to blow, protecting
the wiring harness from damage.
Checking and replacing
fuses
If any of the electrical components
do not operate, a fuse may have
blown. If this happens, check and
replace the fuses as necessary.
Checking and replacing fuses
A
B

3926-3. Do-it-yourself maintenance
WARNING
■To prevent injury
Before performing any light bulb
replacement procedure, be sure to turn
the engine switch off. Failure to do so
may result in burns from hot components
or a part of your bo dy may get caught on
an operating component, possibly caus-
ing serious injury.
■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
unavoidable 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
water entering the headlight unit. This
may damage the headlights or cause
condensation to build up on the lens.
●Do not attempt to repair or disassem-
ble the light bulbs, connectors, electric
circuits or component parts.
Doing so may result in death or serious
injury due to electric shock.
■To prevent damage or fire
●Make sure bulbs are fully seated and
locked.
●Check the wattage of the bulb before
installing to prev ent heat damage.

4107-2. Steps to take in an emergency
The light 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.
■Electric power steering system warning
light (warning buzzer)
When the battery charge becomes insuffi-
cient or the voltage temporarily drops, the
electric power steeri ng system warning
light may come on and the warning buzzer
may sound.
■When the tire pressure warning light
comes on
Inspect the tires to check if a tire is punc-
tured.
If a tire is punctured: P.416
If none of the tires are punctured:
Turn the engine switch off then turn it to
IGNITION ON mode. Check if the tire
pressure warning light comes on or blinks.
If the tire pressure wa rning light blinks for
1 minute then stays on
There may be a malfunction in the tire
pressure warning syst em. Have the vehicle
inspected by your Lexus dealer immedi-
ately.
If the tire pressure warning light comes
on
1 After the temperature of the tires has
lowered sufficiently, check the inflation
pressure of each tire and adjust them to
the specified level.
2 If the warning light does not turn off
even after several minutes have
elapsed, check that the inflation pres-
sure of each tire is at the specified level
and perform initialization. ( P.371)
If the warning light does not turn off several
minutes after the initia lization has been per-
formed, have the vehicle inspected by your
Lexus dealer immediately.
■The tire pressure warning light may
come on due to natural causes
The tire pressure wa rning light may come
on due to natural causes such as natural air
leaks and tire inflation pressure changes
caused by temperature. In this case, adjust-ing the tire inflation pressure will turn off the
warning light (after a few minutes).
■When a tire is replaced with a spare tire
The compact spare tire is not equipped with
a tire pressure warning valve and transmit-
ter. If a tire goes flat , the tire pressure warn-
ing 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 inflation pressure. The
tire pressure warning light will go off after a
few minutes.
■Conditions that the tire pressure warn-
ing system may not function properly
 P.368
■Customization
Some functions can be customized.
(  P.461)
WARNING
■If both the ABS and the brake system
warning lights remain on
Stop your vehicle in a safe place immedi-
ately and contact your Lexus dealer.
The vehicle will become extremely
unstable during br aking, and the ABS
system may fail, which could cause an
accident resulting in death or serious
injury.
■When the electric power steering
system warning light comes on
When the light comes on yellow, the
assist to the power st eering is restricted.
When the light comes on red, the assist
to the power steering is lost and handling
operations of the steering wheel become
extremely heavy.
When steering wheel operations are
heavier than usual, grip the steering
wheel firmly and operate it using more
force than usual.

4267-2. Steps to take in an emergency
7Confirm it is not loose after tighten-
ing:
1 Push and pull the tire
2 Try rotating
Visually check to ensure tire is not hung on
surrounding parts.
If looseness or misassembly exists, repeat
steps 2 to 7.
8 Repeat step 7, any time the tire is
lowered or disturbed.
9 Stow the jack and all tools.
■The compact spare tire
●The compact spare tire is identified by the
label “TEMPORARY USE ONLY” on
the tire sidewall. Use the compact spare
tire temporarily, and only in an emer-
gency.
●Make sure to check the tire inflation pres-
sure of the compact spare tire. ( P.448)
■When using the compact spare tire
As the compact spare tire is not equipped
with a tire pressure warning valve and trans-
mitter, low inflation pressure of the spare
tire will not be indicated by the tire pressure
warning system. Also, if you replace the
compact spare tire after the tire pressure
warning light comes on, the light remains
on.
■When the compact spare tire is
equipped
When driving with the compact spare tire
installed, the vehicle he ight will be different
than when driving with standard tires.
■If you have a flat front tire on a road cov-
ered with snow or ice
Install the compact spare tire on one of the
rear wheels of the vehicle. Perform the fol-
lowing steps and fit tire chains to the front
tires:
1 Replace a rear tire with the compact
spare tire.
2 Replace the flat front tire with the tire
removed from the rear of the vehicle.
3 Fit tire chains to the front tires.
WARNING
■When using the compact spare tire
●Remember that the compact spare tire
provided is specific ally designed for
use with your vehicle. Do not use your
compact spare tire on another vehicle.
●Do not use more than one compact
spare tire simultaneously.
●Replace the compact spare tire with a
standard tire as soon as possible.
●Avoid sudden acceleration, abrupt
steering, sudden br aking and shifting
operations that cause sudden engine
braking.
■When the compact spare tire is
attached
The vehicle speed may not be correctly
detected, and the following systems may
not operate correctly:
• ABS & Brake assist
•VSC
•TRAC
• Trailer Sway Control
•EPS
•VDIM (if equipped)
• Adaptive Variable Suspension System (if equipped)
• Dynamic radar cruise control with full-speed range

4297-2. Steps to take in an emergency
7
When trouble arises
The engine starting system may be
malfunctioning due to an electrical
problem such as electronic key battery
depletion or a blown fuse. However, an
interim measure is available to start the
engine. (P.429)
One of the following may be the cause
of the problem:
 One or both of the battery terminals
may be disconnected. ( P.363)
 The battery may be discharged.
( P.433)
 There may be a malfunction in the
steering lock system.
Contact your Lexus dealer if the problem
cannot be repaired, or if repair procedures
are unknown.
When the engine does not start, the
following steps can be used as an
interim measure to start the engine if
the engine switch is functioning nor-
mally.
Do not use this starting procedure
except in cases of emergency.
1 Turn the engine switch to IGNI-
TION ON mode and check that the parking brake is set. (
P.177,
183)
2 Shift the shift lever to P.
3 Turn the engine switch to ACCES-
SORY mode.
4 Press and hold the engine switch
for about 15 seconds while
depressing the brake pedal firmly.
Even if the engine can be started using
the above steps, the system may be
malfunctioning. Have the vehicle
inspected by your Lexus dealer.
The starter motor does not turn
over
The starter motor does not turn
over, the interior lights and head-
lights do not turn on, or the horn
does not sound.
Starting the engine in an emer-
gency

491What to do if... (Troubleshooting)
Is the engine switch in IGNITION
ON mode?
If you cannot release the shift lever by
depressing the brake pedal with the engine
switch in IGNITION ON mode ( P.179)
It is locked automatically to prevent
theft of the vehicle. ( P.175)
 Is the window lock switch pressed?
The power window except for the one at
the driver’s seat cannot be operated if the
window lock switch is pressed. ( P.146)
 The auto power off function will be
operated if the vehicle is left in
ACCESSORY or IGNITION ON
mode (the engine is not running) for
a period of time. ( P.177)
 The seat belt reminder light is flash-
ing
Are the driver and the passengers wearing
the seat belts? ( P.406)
 The parking brake indicator is on
Is the parking brake released? ( P.183)
Depending on the situation, other
types of warning buzzer may also
sound. ( P.403, 412)
 Did anyone inside the vehicle open
a door during setting the alarm?
The sensor detects it and the alarm sounds.
( P.68)
Do one of the following to stop the
alarms:
 Unlock the doors.
 Turn the engine switch to ACCES-
SORY or IGNITION ON mode, or
start the engine.
 Is the message displayed on the
multi-information display?
Check the message on the multi-informa-
tion display. ( P.412)
 When a warning light turns on or a
warning message is displayed, refer
to P.403, 412.
The steering wheel cannot be
turned after the engine is
stopped
The windows do not open or
close by operating the power
window switches
The engine switch is turned off
automatically
A warning buzzer sounds during
driving
An alarm is activated and the
horn sounds
A warning buzzer sounds when
leaving the vehicle
A warning light turns on or a
warning message is displayed
When a problem has occurred
If you have a flat tire

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

503Alphabetical Index
Rear window and outside rear view mir-ror defoggers switch ............................ 292
Seat heater switches ................................306
Seat ventilator switches ..........................306
“SOS” button .................................................. 60
Tilt and telescopic steering control switch ...........................................................................139
Tire pressure warning reset switch .... 371
Vehicle-to-vehicle distance switch ...227
VSC OFF switch ....................................... 276
Window lock switch ..................................146
Windshield wiper and washer switch194
Windshield wiper de-icer switch ...... 297
T
Tachometer........................................................ 77 Rev indicator ................................................... 78
Rev peak ........................................................... 79
Tail lights Light switch .................................................... 188
Replacing light bulbs............................... 385
The Secondary Collision Brake ............ 275
Theft deterrent system Alarm .................................................................. 68
Engine immobilizer system ..................... 66
Tire inflation pressure Maintenance data......................................448
Tire inflation pressu re display function
......................................................................... 367
Warning light ............................................... 407
Tire information ............................................ 452 Glossary.........................................................456
Size.................................................................... 454
Tire identification number ..................... 453
Uniform Tire Quality Grading............ 454
Tire pressure display .................................. 367
Tire pressure warning system Function .......................................................... 367
Initializing ......................................................... 371
Installing tire pressure warning valves and transmitters ...................................... 370
Registering ID codes ............................... 372 Warning light ...............................................407
Tires Chains .............................................................. 281
Checking ...................................................... 365
If you have a flat tire ................................... 416
Inflation pressure ........................................ 373
Information ....................................................452
Replacing ........................................................ 416
Rotating tires ................................................ 367
Size ................................................................... 448
Snow tires ..................................................... 280
Spare tire ......................................................... 416
Tire inflation pressure display function.......................................................................... 367
Tire pressure warning system ............. 367
Warning light ...............................................407
Tools.................................................................... 417
Top tether strap............................................... 57
Total load capacity ...................................... 442
Towing Dinghy towing ...............................................173
Emergency towing.................................... 397
Towing eyelet.............................................. 399
Trailer towing ................................................ 163
TRAC (Traction Control) ........................ 275
Traction Control (TRAC) ........................ 275
Trailer Sway Control.................................. 275
Trailer towing ..................................................163
Transmission Automatic transmission ........................... 178
Driving mode select switch .................... 271
M mode ............................................................. 181
Paddle shift switches ........................ 180, 181
Trip meters ........................................................ 80
Turn signal lights Replacing light bulbs ............................... 385
Turn signal lever .......................................... 182
Wattage ..........................................................449
U
USB charging ports.................................... 322