2018 LEXUS RC300 ignition

4877-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 7
When trouble arises Once  The engine switch has been turned
off with the shift lever in a position
other than P or N.
 Shift the shift lever to P.
Once  After the engine switch has been
turned off with the shift lever in a
position other than P, the shift lever
has been shifted to P.
 Turn the engine switch off.
  Power was turned off due to the
automatic power off function.
 Next time when starting the
engine, increase the engine
speed slightly and maintain that
level for approximately 5 min-
utes to recharge the battery.
Con-
tinuous  Indicates that the engine was
stopped in an emergency while driv-
ing
 To restart the engine, shift the
shift lever to N and turn the
engine switch to IGNITION
ON mode.
*Interior
buzzer Exterior
buzzer Warning message Details/Actions (Flashes)
(Flashes)
(Flashes)

520 7-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)Ensure that the shift lever is in P and depress the brake pedal.
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 cus-
tomization setting, the engine switch will
turn to ACCESSORY mode.
Firmly depress the brake pedal and check that is shown on the multi-
information display.
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. ■
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. 427)■
Changing engine switch modes
Release the brake pedal and press the engine switch in step above.
The engine does not start and modes will be changed each time the switch is pressed.
(  P. 208) ■
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. 569)●
Check if battery-saving mode is set. If it is set, cancel the function. (  P. 158)Starting the engine 1
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4
3

524 7-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)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 battery of
your vehicle.
Open and close any of the door of your vehicle with the engine switch off.
Maintain the engine speed of the second vehicle and start the engine of your
vehicle by turning the engine switch to IGNITION ON mode.
Once the vehicle’s engine has started, remove the jumper cables in the exact
reverse order from which they were connected.
Once the engine starts, have the vehicle inspected at your Lexus dealer as soon
as possible. ■
Starting the engine when the battery is discharged
The engine cannot be started by push-starting. ■
To prevent battery discharge ●
Turn off the headlights and the audio system while the engine is off. ●
Turn off any unnecessary electrical componen ts when the vehicle is running at a low
speed for an extended period , such as in heavy traffic.■
Charging the battery
The electricity stored in the battery will disc harge gradually even when the vehicle is not
in use, due to natural discharge and the draini ng effects of certain electrical appliances. If
the vehicle is left for a long time, the battery may discharge, and the engine may be
unable to start. (The battery recharges automatically during driving.) ■
When recharging or replacing the battery ●
In some cases, it may not be possible to un lock the doors using the smart access system
with push-button start when the battery is discharged. Use the wireless remote control
or the mechanical key to lock or unlock the doors. ●
The engine may not start on the first attempt after the battery has recharged but will
start normally after the second attempt. This is not a malfunction. ●
The engine switch mode is memorized by the vehicle. When the battery is recon-
nected, the system will return to the mode it was in before the battery was discharged.
Before disconnecting the battery, turn the engine switch off.
If you are unsure what mode the engine switch was in before the battery discharged, be
especially careful when reconnecting the battery. 5
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544 8-1. Specifications
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)* : The fluid capacity is a reference quantity.
If replacement is necessary, contact your Lexus dealer.
■
Spark plugCooling system Capacity
* RC350/
RC300
AWD 10.0 qt. (9.5 L, 8.4 Imp. qt.)
RC300 
Gasoline engine
8.5 qt. (8.0 L, 7.0 Imp. qt.) 
Intercooler
3.3 qt. (3.1 L, 2.7 Imp. qt.)
RC F 12.2 qt. (11.5 L, 10.1 Imp. qt.)
Coolant type Use either of the following:
• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based non-sili-
cate, non-amine, non-nitrite, and non-borate coolant
with long-life hybrid organic acid technology
Do not use plain water alone.
Ignition system RC350/RC300
AWD RC300 RC F
Make DENSO
FK20HBR8 NGK
DILFR7K9G DENSO
FK20HBR-J8
Gap 0.031 in. (0.8 mm) 0.035 in. (0.9 mm) 0.031 in. (0.8 mm)
NOTICE ■
Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.

5778-2. Customization
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 8
Vehicle specifications ■
Seat belt reminder (  P. 455)■
Vehicle customization ●
When the smart access system with push-button start is off, the entry unlock function
cannot be customized. ●
When the doors remain closed after unlocking the doors and the timer activated auto-
matic door lock function activates, signals will be generated in accordance with the
operation buzzer volume and operational si gnal (Emergency flashers) function set-
tings. ●
Some settings can be changed using a switch or the Center Display. If a setting is
changed using a switch, the ch anged setting will not be refl ected on the Center Display
screen until the engine switch is turn ed off and then to IGNITION ON mode.■
When customizing usin g the Remote Touch
Stop the vehicle in a safe place, apply the parking brake, and shift the shift lever to P. Also,
to prevent battery discharge, leave the engine running while customizing the features. Function Default setting Customized setting
Vehicle speed linked seat belt
reminder buzzer On Off — O 1 2
WARNING ■
During customization
As the engine needs to be running during customization, ensure that the vehicle is
parked in a place with adequate ventilation. In a closed area such as a garage, exhaust
gases including harmful carbon monoxide (CO) may collect and enter the vehicle. This
may lead to death or a serious health hazard.
NOTICE ■
During customization
To prevent battery discharge, ensure that the engine is running while customizing fea-
tures.

612
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)What to do if... (Troubleshooting)
What to do if... (Troubleshooting) ●
If you lose your mechanical keys, ne w genuine mechanical keys can be made
by your Lexus dealer. (  P. 142)●
If you lose your electronic keys, the risk of vehicle theft increases significantly.
Contact your Lexus dealer immediately. (  P. 144)●
Is the electronic key battery weak or depleted? (  P. 427)●
Is the engine switch in IGNITION ON mode?
When locking the doors, turn the engine switch off. (  P. 208)●
Is the electronic key left inside the vehicle?
When locking the doors, make sure that you have the electronic key on your
person. ●
The function may not operate properly du e to the condition of the radio wave.
(  P. 158)
●
The function to prevent the electronic key from being left inside the trunk will
operate and you can open th e trunk as usual. Take the key out from the trunk.
(  P. 153)If you have a problem, check the foll owing before contacting your Lexus
dealer.
The doors cannot be locked, unlocked, opened or closed You lose your keys
The doors cannot be locked or unlocked
The trunk lid is closed with the electronic key left inside

613What to do if... (Troubleshooting)
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)●
Did you press the engine switch while firmly depressing the brake pedal?
(  P. 207)●
Is the shift lever in P? (  P. 210)●
Is the electronic key anywhere detectable inside the vehicle? (  P. 156)●
Is the steering wheel unlocked? (  P. 210)●
Is the electronic key battery weak or depleted?
In this case, the engine can be started in a temporary way. (  P. 520)●
Is the battery discharged? (  P. 522)●
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. 219)●
It is locked automatically to prevent theft of the vehicle. (  P. 210)
●
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. 182)
●
The auto power off function will be operated if the vehicle is left in ACCES-
SORY or IGNITION ON mode (the engine is not running) for a period of
time. (  P. 210)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
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

614 What to do if... (Troubleshooting)
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)●
The seat belt reminder light is flashing
Are the driver and the front passe nger wearing the seat belts? (  P. 455)●
The parking brake indicator is on
Is the parking brake released? (  P. 222)
Depending on the situation, other type s of warning buzzer may also sound.
(  P. 453, 460)
●
Did anyone inside the vehicle open a door during setting the alarm?
The sensor detects it and the alarm sounds. (  P. 80)
Do one of the following to de activate or stop the alarms:• Unlock the doors.
• Open the trunk using the entry function or wireless remote control.
• Turn the engine switch to ACCESSORY or IGNITION ON mode, or start the
engine.
●
Is the electronic key left inside th e vehicle or the moon roof opened?
Check the message on the multi-information display. (  P. 460)
●
When a warning light turns on or a wa rning message is displayed, refer to
P. 453, 460. 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