2020 LEXUS RC300 check engine light

2556-3. Do-it-yourself maintenance
6
Maintenance and care
■Brake fluid can absorb moisture from
the air
Excess moisture in the brake fluid can cause
a dangerous loss of braking efficiency. Use
only newly opened brake fluid.
Check the battery as follows.
■Battery exterior
Make sure that the battery terminals
are not corroded and that there are no
loose connections, cracks, or loose
clamps. Terminals
Hold-down clamp
■Before recharging
When recharging, the battery produces
hydrogen gas which is flammable and
explosive. Therefore, observe the following
before recharging:
●If recharging with the battery installed on
the vehicle, be sure to disconnect the
ground cable.
●Make sure the power switch on the char-
ger is off when connecting and discon-
necting the charger cables to the battery.
■After recharging/reconnecting the bat-
tery
The engine may not start. Follow the proce-
dure below to initialize the system.
1
Shift the shift lever to P.
2
Open and close either door.
3
Restart the engine.
●Unlocking the doors using the smart
access system with pu sh-button start may
not be possible immediately after recon-
necting the battery. If this happens, use
the wireless remote control or the
mechanical key to lock/unlock the doors.
●Start the engine with the engine switch in
ACCESSORY mode. The engine may
not start with the engine switch turned off.
However, the engine will operate nor-
mally from the second attempt.
●The engine switch mode is recorded by
the vehicle. If the battery is disconnected
and reconnected, the vehicle will return
the engine switch mode to the status it
was in before the battery was discon-
nected. Make sure to turn off the engine
before disconnecting the battery. Take
extra care when connecting the battery if
the engine switch mode prior to the bat-
tery being disconnected is unknown.
If the system will not start even after multi-
ple attempts, contact your Lexus dealer.
WARNING
■When filling the reservoir
Take care as brake fluid can harm your
hands and eyes and damage painted sur-
faces.If fluid gets on your hands or in your
eyes, flush the affected area with clean
water immediately.
If you still experience discomfort, see a
doctor.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go
down slightly as the brake pads wear out
or when the fluid level in the accumulator
is high.
If the reservoir need s frequent refilling,
there may be a serious problem.
Battery
A
B

2606-3. Do-it-yourself maintenance
information will not be updated.
If this accidentally occurs, either turn the
engine switch to off and then to IGNITION
ON mode, or initialize the system after
checking that the tire pressure is properly
adjusted.
Your vehicle is equipped with a tire
pressure warning system that uses tire
pressure warning valves and transmit-
ters to detect low tire inflation pressure
before serious problems arise.
 If the tire pressure drops below a
predetermined level, the driver is
warned by a screen display and a
warning light. ( P.289)
 The tire pressure detected by the
tire pressure warning system can be
displayed on the multi-information
display. ( P.69)
The illustration used is intended as an
example, and may differ from the image
that is actually displayed on the multi-infor-
mation display.
■Routine tire inflation pressure checks
The tire pressure warning system does not
replace routine tire inflation pressure
checks. Make sure to check tire inflation
pressure as part of your routine of daily
vehicle checks.
■Situations in which the tire pressure
warning system may not operate prop-
erly
●In the following cases, the tire pressure
warning system may not operate prop-
erly.
• If non-genuine Lexus wheels are used.
• A tire has been replaced with a tire that is not an OE (Original Equipment) tire.
• A tire has been replaced with a tire that is not of the specified size.
• Tire chains, etc. are equipped.
• An auxiliary-supported run-flat tire is equipped.
• If a window tint that affects the radio wave signals is installed.
• If there is a lot of snow or ice on the vehi-
cle, particularly around the wheels or
wheel housings.
• If the tire inflation pressure is extremely
higher than the specified level.
• If tires not equipped with tire pressure warning valves and transmitters are used.
• If the ID code on the tire pressure warn- ing valves and transmitters is not regis-
tered in the tire pressure warning
computer.
●Performance may be af fected in the fol-
lowing situations.
• Near a TV tower, electric power plant, gas station, radio stat ion, large display,
airport or other fac ility that generates
strong radio waves or electrical noise
• When carrying a portable radio, cellular
phone, cordless phone or other wireless
communication device
If tire position information is not correctly
displayed due to the radio wave conditions,
the display may be corrected by driving and
changing the radio wave conditions.
●When the vehicle is parked, the time
taken for the warning to start or go off
could be extended.
●When tire inflation pr essure declines rap-
idly for example when a tire has burst, the
warning may not function.
Tire pressure warning system

2887-2. Steps to take in an emergency
■Open door warning light (warning buzzer)*
*: Open door warning buzzer: P.88
■Low fuel level warning light
■Driver’s and front passenger’s seat belt reminder light (warning buzzer)*
*: Driver’s seat belt warning buzzer:
The driver’s seat belt warning buzzer sounds to al ert the driver that his or her seat belt is not
fastened. Once the engine switch is turned to IGNITION ON mode, the buzzer sounds. If
the seat belt is still unfastened, the buzzer sounds intermittently for a certain period of time
after the vehicle reaches a certain speed.
Front passenger’s seat belt warning buzzer:
The front passenger’s seat belt warning buzzer sounds to alert the front passenger that his
or her seat belt is not fastened. If the seat be lt is unfastened, the buzzer sounds intermittenly
for a certain period of time after the vehicle reaches a certain speed.
■Rear passengers’ seat belt r eminder lights (warning buzzer)*
*: Rear passengers’ seat belt warning buzzer:
The rear passengers’ seat belt warning buzzer sounds to alert the rear passenger that his or
her seat belt is not fastened. If the seat belt is unfastened, the buzzer sounds intermittently
for a certain period of time, af ter the seat belt is fastened and unfastened and the vehicle
Warning lightDetails/Actions
Indicates that a door or the trunk is not fully closed
 Check that both side doors and the trunk are closed.
Warning lightDetails/Actions
Indicates that remaining fuel is approximately 2.6 gal. (10 L, 2.2 Imp.
gal.) or less
 Refuel the vehicle.
Warning lightDetails/Actions
Warns the driver and/or front pass enger to fasten their seat belts
 Fasten the seat belt.
If the front passenger’s seat is occupied, the front passenger’s seat
belt also needs to be fastened to make the warning light (warning
buzzer) turn off.
Warning lightDetails/Actions
Warns the rear passengers to fasten their seat belts
 Fasten the seat belt.

2907-2. Steps to take in an emergency
■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.
■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 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 the spare
tire
The spare tire is not equipped with a tire
pressure warning valve and transmitter. 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.
■Conditions that the tire pressure warn-
ing system may not function properly
 P.260
■If the tire pressure warning light fre-
quently comes on after blinking for 1
minute
If the tire pressure wa rning light frequently
comes on after blinking for 1 minute when
the engine switch is turned to IGNITION
ON mode, have it checked by your Lexus
dealer.
■Warning buzzer
In some cases, the buzzer may not be heard
due to being in a noisy location or audio
sound.
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 braking, 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
The steering wheel may become
extremely heavy.
When steering wheel operations are
heavier than usual, grip the steering
wheel firmly and operate it using more
force than usual.
■If the tire pressure warning light
comes on
Be sure to observe the following precau-
tions. Failure to do so could cause a 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 infla-
tion pressure immediately.
●If the tire pressure warning light comes
on even after tire inflation pressure
adjustment, it is prob able that you have
a flat tire. Check the tire s. 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 brak-
ing. 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.

2947-2. Steps to take in an emergency
In some situations, the master warning light and warning buzzer may not oper-
ate as specified. In this case, follow the instructions displayed in the warning
message.
 If a warning light comes on or flashes at the same time that a warning message is
displayed, take corrective actio n according to the warning light. ( P.284)
*: A buzzer sounds the first time a message is shown on the multi-information display.
■Warning messages
The warning messages explained below
may differ from the actual messages
according to operation conditions and vehi-
cle specifications.
■Warning buzzer
In some cases, the bu zzer may not be heard
due to being in a noisy location or audio
sound.
■If “Engine Oil Level Low Add or
Replace” is displayed
The engine oil level is low. Check the level
of the engine oil, and add if necessary.
This message may appear if the vehicle is
stopped on a slope. Move the vehicle to a
level surface and check to see if the mes-
sage disappears.
■If “Front Camera Unavailable” or “Front
Camera Unavailable Remove Debris
On Windshield” is displayed
The following systems may be suspended
until the problem shown in the message is
resolved. ( P.154, 287)
●PCS (Pre-Collision System)
●LDA (Lane Departure Alert with steering
control)
●Automatic High Beam
●Dynamic radar cruise control
■If “Maintenance Required Soon” is dis-
played
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.240)
*: Refer to the separate “Scheduled Main-
tenance” or “Owner’s Manual Supple-
ment” for the main tenance interval
applicable to your vehicle.
■If “Maintenance Required Visit Your
Dealer” is displayed
Indicates that all mainte nance 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.240)
*: Refer to the separate “Scheduled Main-
Comes onDoes not sound
Indicates a condition, such as malfunction of electri-
cal components, their cond ition, or indicates the
need for maintenance
FlashesDoes not sound
Indicates a situation, such as when an operation has
been performed incorrectly, or indicates how to
perform an operation correctly
Warning buzzer*Warning

3228-1. Specifications
■Spark plug
*: The fluid capacity is a reference quantity.If replacement is necessary, contact your Lexus dealer.
Ignition system (spark plug)
RC350/RC300 AWDRC300
MakeDENSO FK20HBR8NGK DILFR7K9G
Gap0.031 in. (0.8 mm)0.035 in. (0.9 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Electrical system (battery)
Open voltage at 68°F (20°C):
12.3 V or higher
If the voltage is lower than the standard value,
charge the battery.
(Voltage is checked 20 minutes after the engine
and all lights are turned off.)
Charging rates5 A max.
Automatic transmission
Fluid capacity*
RC350
10.0 qt. (9.5 L, 8.4 Imp. qt.)
RC350 AWD/RC300 AWD
10.6 qt. (10.0 L, 8.8 Imp. qt.)
RC300
9.2 qt. (8.7 L, 7.7 Imp. qt.)
Fluid typeToyota Genuine ATF WS
NOTICE
■Transmission fluid type
Using transmission fluid other than the above type may cause abnormal noise or vibra-
tion, or damage the transmission of your vehicle.

373What 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.130)
 It is locked automatically to prevent
theft of the vehicle. ( P.125)
 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.111)
 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.128)
 The seat belt reminder light is flash-
ing
Are the driver and the front passenger
wearing the seat belts? ( P.288)
 The parking brake indicator is on
Is the parking brake released? ( P.135)
Depending on the situation, other
types of warning buzzer may also
sound. ( P.284, 292)
 Did anyone inside the vehicle open
a door during setting the alarm?
The sensor detects it and the alarm sounds.
( P.57)
Do one of the following to deactivate
or stop the alarm:
 Unlock the doors.
 Open the trunk using the entry
function or wireless remote control.
 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.292)
 When a warning light turns on or a
warning message is displayed, refer
to P.284, 292.
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

378Alphabetical Index
Ignition switch (engine switch) .............125
Overheating.................................................... 311
Tachometer ..................................................... 64
Engine coolant Capacity ........................................................... 321
Checking ....................................................... 252
Preparing and checking before winter.......................................................................... 198
Engine coolant temperature gauge ....... 64
Engine immobilizer system ........................ 56
Engine oil Capacity ......................................................... 320
Checking .......................................................250
Preparing and checking before winter.......................................................................... 198
Warning light ...............................................285
Engine oil maintenance data .................. 252
Engine oil pressure gauge ...........................72
Engine oil temperature gauge ...................72
Engine switch ..................................................125 Auto power off function ...........................128
Changing the engine switch modes.. 127
If your vehicle has to be stopped in an
emergency ................................................ 276
EPS (Electric Power Steering) ................194 Warning light ...............................................286
Event data recorder (EDR) ............................6
F
First-aid kit storage belt .............................. 221
Flat tire Tire pressure warning system .............260
Vehicles with a spare tire ...................... 296
Floor mats ...........................................................22
Fluid Automatic transmission .......................... 322
Brake.................................................... 254, 323
Washer ........................................................... 256
Footwell light ................................................... 217
Front passenger occupant classification system .............................................................. 36 Front position lights
Wattage ..........................................................328
Front seats Adjustment ....................................................... 97
Cleaning ......................................................... 237
Correct driving posture ............................ 23
Driving position memory ........................ 100
Head restraints............................................. 103
Memory recall function............................ 102
Power easy access system .................... 100
Seat heaters ....................................................214
Seat position memory ..............................100
Seat ventilators ..............................................214
Front side marker light Light switch .....................................................137
Front turn signal lights Replacing light bulbs ................................ 272
Turn signal lever ...........................................134
Wattage ..........................................................328
Fuel Capacity .........................................................320
Fuel gauge ........................................................ 64
Fuel pump shut off system.....................283
Information ....................................................329
Refueling.......................................................... 149
Type ..................................................................320
Warning light .............................................. 288
Fuel consumption Average fuel economy ................................ 71
Current fuel consumption .......................... 71
Fuel filler door If the fuel filler do or cannot be opened
......................................................................... 305
Refueling.......................................................... 149
Fuel gauge ......................................................... 64
Fuel pump shut off system........................ 283
Fuses ................................................................. 269
G
Garage door opener ................................. 224
Gauges ............................................................... 64
Gear Position ....................................................73