Page 579 of 640
5798-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
■Locking the door
Move the inside lock button to the
lock position.
Close the door while pulling the door handle.
■Opening the trunk
Turn the mechanical key clockwise
to open.
■Key linked functions
*: These settings must be customized at your Lexus dealer or repairer, or another duly
qualified and equipped professional.
1
2
Locks both side door
Closes the windows and moon roof (if equipped) (turn and hold)*
Unlocks the door
Opens the windows and moon roof (if equipped) (turn and hold)*
1
2
3
4
Page 580 of 640
5808-2. Steps to take in an emergency
RC300h_EE(OM24740E)
Ensure that the shift lever is in P and depress the brake pedal.
Touch the Lexus emblem side of the
electronic key to the power switch.
When the electronic key is detected, a buzzer sounds and the power switch willturn to ON mode.
When the smart entry & start system is deactivated in customization setting, thepower switch will turn to ACCESSORY
mode.
Firmly depress the brake pedal and check that is shown on the multi-
information display.
Press the power switch.
In the event that the hybrid system still cannot be started, contact any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional.
Starting the hybrid system
1
2
3
4
Page 581 of 640

5818-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
■Stopping the hybrid system
Shift the shift lever to P and press the power switch as you normally do when stopping the hybrid system.
■Replacing the key battery
As the above procedure is a temporary measur e, it is recommended that the electronic key battery be replaced immediately when the battery is depleted. ( P. 511)
■Alarm (if equipped)
Using the mechanical key to lock the doors will not set the alarm system. If a door is unlocked using the mechanical key when the alarm system is set, the alarm may be triggered.
■Changing power switch modes
Release the brake pedal and press the power switch in step above. The hybrid system does not start and modes will be changed each time the switch is
pressed. ( P. 216)
■When the electronic key does not work properly
●Make sure that the smart entry & start system has not been deactivated in the
customization setting. If it is off, turn the function on. (Customizable features P. 607)
●Check if battery-saving mode is set. If it is set, cancel the function. (P. 157)
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 children to operate the me chanical key. It is possible for children and other passengers to get caught in the power window or moon roof.
3
Page 583 of 640

5838-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
Open the exclusive jump starting
terminal cover.
Connect the jumper cables according to the following procedure:
Connect a positive jumper cable clamp to the exclusive jump starting ter-
minal on your vehicle.
Connect the clamp on the other end of the positive cable to the positive (+)
battery terminal on the second vehicle.
Connect a negative cable clamp to the negative (-) battery terminal on the
second vehicle.
Connect the clamp at the other end of the negative cable to a solid, station-
ary, unpainted metallic point away from the exclusive jump starting terminal
and any moving parts, as shown in the illustration.
Start the engine of the second vehicle. Increase the engine speed slightly and
maintain at that level for approximately 5 minutes to recharge the 12-volt bat-
tery of your vehicle.
Open and close any of the doors of your vehicle with the power switch off.
Maintain the engine speed of the seco nd vehicle and start the hybrid system
of your vehicle by turning the power switch to ON mode.
3
4
1
2
3
4
5
6
7
Page 584 of 640

5848-2. Steps to take in an emergency
RC300h_EE(OM24740E)
Make sure the “READY” indicator comes on. If the indicator does not come
on, contact any authorized Lexus dealer or repairer, or another duly qualified
and equipped professional.
Once the hybrid system has started, remove the jumper cables in the exact
reverse order from which they were connected.
Once the hybrid system starts, have the vehicle inspected at any authorized
Lexus dealer or repairer, or another duly qualified and equipped professional as
soon as possible.
■Starting the hybrid system when the 12-volt battery is discharged
The hybrid system cannot be started by push-starting.
■To prevent 12-volt battery discharge
●Turn off the headlights and the audio system while the hybrid system 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 12-volt battery
The electricity stored in the 12-volt battery will discharge gradually even when the vehicle
is not in use, due to natural discharge and the draining effects of certain electrical appli- ances. If the vehicle is left for a long time, the 12-volt battery may discharge, and thehybrid system may be unable to start. (The 12-volt battery recharges automatically while
the hybrid system is operating.)
■When recharging or replacing the 12-volt battery
●In some cases, it may not be possible to unlock the doors using the smart entry & start
system when the 12-volt battery is discharg ed. Use the wireless remote control or the mechanical key to lock or unlock the doors.
●The hybrid system may not start on the first attempt after the 12-volt battery has
recharged but will start normally after the second attempt. This is not a malfunction.
●The power switch mode is memorized by the vehicle. When the 12-volt battery is reconnected, the system will return to the mod e it was in before the 12-volt battery was
discharged. Before disconnecting the 12-v olt battery, turn the power switch off. If you are unsure what mode the power switch was in before the 12-volt battery dis-charged, be especially careful when reconnecting the 12-volt battery.
8
9
Page 587 of 640

5878-2. Steps to take in an emergency
8
When trouble arises
RC300h_EE(OM24740E)
●The hybrid system coolant temperature gauge (P. 115) is in the red zone or
a loss of hybrid system power is experi enced. (For example, the vehicle speed
does not increase.)
●“Engine Coolant High Temperature” or “Hybrid System Overheat Output
Power is limited” is shown on the multi-information display.
●Steam comes out from under the hood.
■If the needle of the engine coolant temperature gauge enters the red zone
or “Engine Coolant High Temperature” is shown on the multi-information
display
Stop the vehicle in a safe place and turn off the air conditioning system, and
then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the hybrid system has
cooled down sufficiently, inspect
the hoses and radiator core (radi-
ator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact any autho- rized Lexus dealer or repairer, oranother duly qualified and
equipped professional.
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2
Page 588 of 640

5888-2. Steps to take in an emergency
RC300h_EE(OM24740E)
The coolant level is satisfactory if
it is between the “FULL” and
“LOW” lines on the reservoir.
Reservoir
“FULL”
“LOW”
Add coolant if necessary.
Water can be used in an emergency if coolant is unavailable.
Start the hybrid system and turn the air conditioning system on to check
that the radiator cooling fans operate and to check for coolant leaks from
the radiator or hoses.
The fans operate when the ai r conditioning system is turned on immediately after a cold start. Confirm that the fans are op erating by checking the fan sound and air flow. If it is difficult to check these, tu rn the air conditioning system on and off
repeatedly. (The fan may not operate in freezing temperatures.)
If the fans are not operating:
Stop the hybrid system immediately and contact any authorized Lexus
dealer or repairer, or another duly qualified and equipped professional.
If the fans are operating:
Have the vehicle inspected at the nearest authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
4
1
2
3
5
6
7
Page 590 of 640

5908-2. Steps to take in an emergency
RC300h_EE(OM24740E)
Start the hybrid system and check for the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
If the message is not displayed:
Have the vehicle inspected at the nearest authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
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 h ood, do not open the hood until the steam has subsided. The engine compartment may be very hot.
●After the hybrid system has been turned off, check that the “READY” indicator is off.
When the hybrid system operating, the ga soline engine may automatically start, or the cooling fan may suddenly operate even if the gasoline engine stops. Do not touchor approach rotating parts such as the belt and fan, which may lead to fingers or
clothing (especially a tie, a scarf or a mu ffler) getting caught, resulting in serious injury.
6
●Do not loosen the coolant reservoir caps orradiator cap while the hybrid system and radi-
ator are hot. High temperature steam or coolant couldspray out.