ignition LEXUS RC350 2018 Workshop Manual

4146-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)
■How to initialize the tire pressure warning system
Park the vehicle in a safe place and turn the engine switch off.
Initialization cannot be performed while the vehicle is moving.
Adjust the tire inflation pressure to th e specified cold tire inflation pressure
level. ( P. 548)
Make sure to adjust the tire pressure to the specified cold tire inflation pressure
level. The tire pressure warning system will operate based on this pressure level.
Turn the engine switch to IGNITION ON mode.
Press and hold the tire pressure
warning reset switch until the tire
pressure warning light blinks
slowly 3 times.
Wait for a few minutes with the engine switch in IGNITION ON mode and
then turn the engine switch off.
◆Registering ID codes
The tire pressure warning valve and tran smitter is equipped with a unique ID
code. When replacing a tire pressure warning valve and transmitter, it is nec-
essary to register the ID code. Have the ID code registered by your Lexus
dealer.
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4156-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)
6
Maintenance and care
■When to replace your vehicle’s tires
Tires should be replaced if:
●The treadwear indicators are showing on a tire.
●You have tire damage such as cuts, splits, cracks deep enough to expose the fabric, and
bulges indicating internal damage
●A tire goes flat repeatedly or cannot be properly repaired due to the size or location of
a cut or other damage
If you are not sure, consult your Lexus dealer.
■Replacing tires and wheels
If the ID code of the tire pressure warning valve and transmitter is not registered, the tire
pressure warning system will not work proper ly. After driving for about 20 minutes, the
tire pressure warning light blinks for 1 minu te and stays on to indicate a system malfunc-
tion.
■Tire life
Any tire over 6 years old must be checked by a qualified technician even if it has seldom
or never been used or damage is not obvious.
■Routine tire inflation pressure checks
The tire pressure warning syst em does not replace routine tire inflation pressure checks.
Make sure to check tire inflat ion pressure as part of your routine of daily vehicle checks.
■When rotating the tires
Make sure that the engine switch is off. If the tires are rotated while the engine switch is in
IGNITION ON mode, the tire position 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 th at the tire pressure is properly adjusted.
■Low profile tires
Generally, low profile tires will wear more rapidly and tire grip performance will be
reduced on snowy and/or icy roads when comp ared to standard tires. Be sure to use
snow tires or tire chains on snowy and/or icy roads and drive carefully at a speed appro-
priate for road and weather conditions.

4487-2. Steps to take in an emergency
RC350_RC300 AWD_RC300_RC F_U(OM24748U)
Insert the towing eyelet into the hole
and tighten partially by hand.
Tighten down the towing eyelet
securely using a wheel nut wrench
or hard metal bar.
Securely attach cables or chains to the towing eyelet.
Take care not to damage the vehicle body.
Enter the vehicle being towed and start the engine.
If the engine does not start, turn the engine switch to IGNITION ON mode.
Shift the shift lever to N and release the parking brake.
When the shift lever cannot be shifted: P. 219
■While towing
If the engine is not running, the power assist for the brakes and steering will not function,
making steering and br aking more difficult.
■Wheel nut wrench
Wheel nut wrench is installed in trunk. ( P. 490, 504)
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4567-2. Steps to take in an emergency
RC350_RC300 AWD_RC300_RC F_U(OM24748U)
*1: Parking brake engaged warning buzzer (RC350/RC300):
 P. 464
*2: Open door warning buzzer:
 P. 462
*3: Driver’s seat belt buzzer:
The driver’s seat belt buzzer sounds to alert the driver that his or her seat belt is not
fastened. Once the engine switch is turned to IGNITION ON mode, the buzzer
sounds for 6 seconds. If the vehicle reaches a speed of 12 mph (20 km/h), the buzzer
sounds once. If the seat belt is still unfast ened after 24 seconds, the buzzer will sound
intermittently for 6 seconds. Then, if the se at belt is still unfastened, the buzzer will
sound in a different tone for 90 more seconds.
Front passenger’s seat belt buzzer:
The front passenger’s seat belt buzzer soun ds to alert the front passenger that his or
her seat belt is not fastened. The buzzer so unds once if the vehicle reaches a speed of
12 mph (20 km/h). If the seat belt is still unfastened after 24 se conds, the buzzer will
sound intermittently for 6 seconds. Then, if the seat belt is still unfastened, the buzzer
will sound in a different to ne for 90 more seconds.
Rear passenger’s seat belt buzzer:
The rear passenger’s seat belt buzzer sounds to alert the rear passenger that his or
her seat belt is not fastened. The buzzer so unds once if the vehicle reaches a speed of
12 mph (20 km/h). If the seat belt is still unfastened after 24 se conds, the buzzer will
sound intermittently for 6 seconds. Then, if the seat belt is still unfastened, the buzzer
will sound in a different tone for 24 more seconds.

4577-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)
7
When trouble arises
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (door), side impact sensors (front), side im pact sensors (rear), driver’s
seat position sensor, driver’s seat belt buckle switch, front passenger occupant classifica-
tion system, “AIR BAG ON” indicator light, “A IR BAG OFF” indicator light, front passen-
ger’s seat belt buckle switch, seat belt pretensioners, airbags, interconnecting wiring and
power sources. ( P. 41)
■Front passenger detection sensor, seat belt reminder and warning buzzer
If luggage is placed on the front passenger seat, the front passenger detection sensor
may cause the warning light to flash and the warning buzzer to sound even if a passenger
is not sitting in the seat.
■If the malfunction indicator lamp comes on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fu el tank immediately.
●Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving trips.
If the light does not go off even after severa l trips, contact your Lexus dealer as soon as
possible.
■Electric power steering system warning light (warning buzzer)
When the battery charge becomes insufficien t or the voltage temporarily drops, the
electric power steering system warning li ght may come on and the warning buzzer may
sound.
■When the tire pressure warning light comes on
Check the tire inflation pressu re and adjust to the appropriate level. Pushing the tire
pressure warning reset switch will not tu rn 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 caus ed by temperature. In this case, adjusting
the tire inflation pressure will turn off the warning light (after a few minutes).
■When a tire is replaced with the spare tire (if equipped)
The spare tire is not equipped with a tire pr essure 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 wa rning system may not function properly
 P. 417
■If the tire pressure warning light freque ntly comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute when the
engine switch is turned to IGNITION ON mo de, 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.

4867-2. Steps to take in an emergency
RC350_RC300 AWD_RC300_RC F_U(OM24748U)
Once
• When the doors were unlocked
with the mechanical key and then
the engine swit ch was pressed,
the electronic key could not be
detected in the vehicle.
• The electronic key could not be detected in the vehicle even after
the engine switch was pressed
two consecutive times.
 Touch the electronic key to the
engine switch while depressing
the brake pedal.
Once
During an engine starting proce-
dure in the event that the electronic
key was not functioning properly
( P. 520), the engine switch was
touched with the electronic key.
 Press the engine switch within
10 seconds of the buzzer sound-
ing.

Indicates that:
• With the engine switch off, the
doors were unlocked and then the
driver's door was opened and
closed.
• The engine switch was turned to ACCESSORY mode without
starting the engine.
• The shift lever wa s shifted to P or
N from another shift position with
the engine switch in IGNITION
ON mode.
 Press the engine switch while
depressing the brake pedal.
Interior
buzzerExterior buzzerWarning messageDetails/Actions

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
buzzerExterior buzzerWarning messageDetails/Actions
(Flashes)
(Flashes)
(Flashes)

5207-2. Steps to take in an emergency
RC350_RC300 AWD_RC300_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
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5247-2. Steps to take in an emergency
RC350_RC300 AWD_RC300_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 components 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.
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5448-1. 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 plug
Cooling 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 F12.2 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
AWDRC300RC F
MakeDENSO
FK20HBR8NGK
DILFR7K9GDENSO
FK20HBR-J8
Gap0.031 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.