check engine LEXUS RC300 2020 Service Manual

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

2957-2. Steps to take in an emergency
7
When trouble arises
tenance” or “Owner’s Manual Supple-
ment” for the maintenance interval
applicable to your vehicle.
■If “Oil Maintenance Required Soon” is
displayed
Indicates that the engine oil is scheduled to
be changed. (The indicator will not work
properly unless the oil maintenance data
has been reset.)
Check the engine oil, and change if neces-
sary. After changing the engine oil, the oil
change system shou ld be reset. (P.252)
■If “Oil Maintenance Required” is dis-
played
Indicates that the engine oil should be
changed. (After the engine oil is changed
and the oil maintenance data has been
reset.)
Check and change the en gine oil, and oil fil-
ter by your Lexus deal er. After changing the
engine oil, the oil change system should be
reset. ( P.252)
■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 “See Owner’s Manual” is displayed
●If the following messages are shown, fol-
lowing the instructions, accordingly.
• “Engine Coolant Temp High” ( P.311)
●If any of the following messages are
shown on the multi-information display, it
may indicate a malfunction. Have the
vehicle inspected by your Lexus dealer
immediately.
• “Braking Power Low”
• “Access System with Elec. Key Malfunc- tion”
●If any of the following messages are
shown on the multi-information display, it
may indicate a malfunction. Immediately
stop the vehicle and contact your Lexus
dealer.
• “Oil Pressure Low”
• “Charging System Malfunction” NOTICE
■“High Power Consumption Partial
Limit On AC/Heater Operation” is
frequently shown
There is a possible malfunction relating
to the charging system or the battery
may be deteriorating. Have the vehicle
inspected by your Lexus dealer.

3067-2. Steps to take in an emergency
■When the electronic key does not work
properly
●Make sure that the smart access system
with push-button start has not been deac-
tivated in the customization setting. If it is
off, turn the function on.
●Check if battery-saving mode is set. If it is
set, cancel the function. ( P.94)
■Unlocking the door
Use the mechanical key ( P.82) in
order to perform the following opera-
tions: 1
Insert the mechanical key while
pulling on the driver’s door handle.
2
Unlocking the door.
3
Remove the key, return the handle,
and then pull the handle again.
■Locking the door
1
Move the inside lock button to the
lock position.
2
Close the door.
■Opening the trunk
Turn the mechanical key clockwise to
open. ( P.57)
If the electronic key does not
o
perate properly
If communication between the
electronic key and vehicle is inter-
rupted ( P.94) or the electronic
key cannot be used because the
battery is depleted, the smart
access system with push-button
start and wireless remote control
cannot be used. In such cases, the
doors and trunk can be opened and
the engine can be started by follow-
ing the procedure below.
NOTICE
■In case of a smart access system with
push-button start malfunction or
other key-related problems
Take your vehicle with all the electronic
keys provided with your vehicle, includ-
ing the card key, to your Lexus dealer.
Locking and unlocking the doors
and opening the trunk

3077-2. Steps to take in an emergency
7
When trouble arises
■Key linked functions
1
Locks both side door
2
Closes the windows and moon roof (if
equipped) (turn and hold)
*
3Unlocks the door
Turning the key rearward unlocks the
driver’s door. Turning the key again unlocks
the other door.
4
Opens the windows and moon roof (if
equipped) (turn and hold)
*
*
: These settings must be customized at
your Lexus dealer.
1Ensure that the shift lever is in P and
depress the brake pedal.
2
Touch the Lexus emblem side of the
electronic key to the engine switch.
When the electronic key is detected, a
buzzer sounds and the engine switch will
turn to IGNITION ON mode.
When the smart access system with
push-button start is deactivated in custom-
ization setting, the engine switch will turn
to ACCESSORY mode.
3Firmly depress the brake pedal and
check that is shown on the
multi-information display.
4
Press the engine switch.
In the event that the engine still cannot
be started, contact your Lexus dealer.
■Stopping the engine
Shift the shift lever to P and press the engine
switch as you normally do when stopping
the engine.
■Electronic key battery
As the above procedure is a temporary
measure, it is recommended that the elec-
tronic key battery be replaced immediately
when the battery is depleted. (P.267)
■Changing engine switch modes
Release the brake pe dal and press the
engine switch in step 3
above.
The engine does not start and modes will be
WARNING
■When using the mechanical key and
operating the power windows or
moon roof
Operate the power window or moon
roof after checking to make sure that
there is no possibility of any passenger
having any of their body parts caught in
the window or moon roof.
Also, do not allow ch ildren to operate the
mechanical key. It is possible for children
and other passengers to get caught in
the power window or moon roof.
Starting the engine

3137-2. Steps to take in an emergency
7
When trouble arises
5Add coolant if necessary.
Water can be used in an emergency if
coolant is unavailable.
Engine (RC350/RC300 AWD)
 Engine (RC300)
 Intercooler (RC300)
6
Start 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.)
7If 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.
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.

3208-1. Specifications
■Oil capacity (Drain and refill [Reference*])
*: The engine oil capacity is a reference quantity to be used when changing the engine oil. Warm up and turn off the engine, wait more than 5 minutes, and check the oil level on the
dipstick.
■Engine oil selection
“Toyota Genuine Motor Oil” is used in
your Lexus vehicle. Use Lexus
approved “Toyota Genuine Motor Oil”
or equivalent to satisfy the following
grade and viscosity.
Oil grade: ILSAC GF-5 multigrade
engine oil
Recommended viscosity: SAE 0W-20
SAE 0W-20 is the best choice for
good fuel economy and good starting
in cold weather. If SAE 0W-20 is not available, SAE
5W-20 oil may be used. However, it
must be replaced with SAE 0W-20 at
the next oil change.
Fuel
Fuel typeUnleaded gasoline only
Octane Rating91 (Research Octane Number 96) or higher
Fuel tank capacity (Reference)17.5 gal. (66.3 L, 14.6 Imp. gal.)
Lubrication system
With filter
RC350
6.0 qt. (5.7 L, 5.0 Imp. qt.)
RC350 AWD/RC300 AWD
6.8 qt. (6.4 L, 5.6 Imp. qt.)
RC300
4.9 qt. (4.6 L, 4.0 Imp. qt.)
Without filter
RC350
5.8 qt. (5.5 L, 4.8 Imp. qt.)
RC350 AWD/RC300 AWD
6.3 qt. (6.0 L, 5.3 Imp. qt.)
RC300
4.5 qt. (4.3 L, 3.8 Imp. qt.)

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.

372What to do if... (Troubleshooting)
1-1.What to do if... (Troubleshooting)What to do if... (Troubleshooting)
If you lose your mechanical keys,
new genuine mechanical keys can
be made by your Lexus dealer.
( P.305)
 If you lose your electronic keys, the
risk of vehicle theft increases signifi-
cantly. Contact your Lexus dealer
immediately. ( P.305)
 Is the electronic key battery weak or
depleted? ( P.267)
 Is the engine switch in IGNITION
ON mode?
When locking the doors, turn the engine
switch off. ( P.127)
 Is the electronic key left inside the
vehicle?
When locking the doors, make sure that
you have the electronic key on your per-
son.
The function may not operate prop-
erly due to the condition of the radio
wave. ( P.94)
 The function to prevent the elec-
tronic key from being left inside the
trunk will operate and you can open
the trunk as usual. Take the key out
from the trunk. ( P.91)
 Did you press the engine switch
while firmly depressing the brake
pedal? ( P.125)
 Is the shift lever in P? ( P.125)
 Is the electronic key anywhere
detectable inside the vehicle?
( P.93)
 Is the steering wheel unlocked?
( P.125)
 Is the electronic key battery weak or
depleted?
In this case, the engine can be started in a
temporary way. ( P.307)
 Is the battery discharged?
( P.308)
If you have a problem, check the
following before contacting your
Lexus dealer.
The doors cannot be locked,
unlocked, opened or closed
You lose your keys
The electronic key does not
operate properly
The doors cannot be locked or
unlocked
The trunk lid is closed with the
electronic key left inside
If you think something is wrong
The engine does not start
The shift lever cannot be shifted
from P even if you depress the
brake pedal