engine overheat LEXUS NX300h 2015 Owners Manual

17Pictorial index
NX300h_U_OM78007U Windshield wipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 228 Precautions against winter season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 326
To prevent freezing (windshield wiper de-icer) . . . . . . . . . . . . . . . . . . . . . . . . . .P. 436
Precautions against car wash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 486
Fuel filler door . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P . 236Refueling method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 236
Fuel type/fuel tank capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 610
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 516 Tire size/inflation pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 615
Winter tires/tire chain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 327
Checking/rotation/tire pressure warning system . . . . . . . . . . . . . . . . . . . . . . . . P. 516
Coping with flat tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 575
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 500Opening. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 500
Engine compartment cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 503
Engine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 611
Coping with overheat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 600
Warning messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 57 2
Headlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 219
Parking lights/daytime running lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 219
Fog lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 227
Turn signal lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P . 212
Tail lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 219
License plate lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 21 9
Back-up light Shifting the shift lever to R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. 208
Side marker lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. 21 94
5
6
7
Light bulbs of the exte rior lights for driving
(Replacing method: P. 538, Watts: P. 617)
* : If equipped8
9
10
11
12
13
14
15

1012. Instrument cluster
2
Instrument cluster
NX300h_U_OM78007U ■
Outside temperature display ●
In the following situations, the correct outside temperature may not be displayed, or the
display may take longer than normal to change.
• When stopped, or driving at low speeds (less than 12 mph [20 km/h])
• When the outside temperature has change d suddenly (at the entrance/exit of a
garage, tunnel, etc.) ●
When “--” or “E” is displayed, the system may be malfunctioning.
Take your vehicle to your Lexus dealer. ■
Pop-up display
In some situations, a pop-up display will be temporarily displayed on the multi-informa-
tion display or the odometer/trip meter/ maintenance required information screen.
The pop-up display function can be set on/off. (  P. 6 3 8 )■
Liquid crystal display
Small spots or light spots may appear on the display. This phenomenon is characteristic
of liquid crystal displays, and there is no problem continuing to use the display.■
Customization
The meter display can be customized on the multi-information display.
(Customizable features:  P. 6 3 3 )
WA R N I N G ■
The information display at low temperatures
Allow the interior of the vehicle to warm up before using the liquid crystal information
display. At extremely low temperatures, th e information display monitor may respond
slowly, and display changes may be delayed.
For example, there is a lag between the driver's shifting and the new gear number
appearing on the display. This lag could cau se the driver to downshift again, causing
rapid and excessive engine braking and po ssibly an accident resulting in personal
death or injury.
NOTICE ■
To prevent damage to the engine and its components ●
When the tachometer is displayed, do not let the indicator needle of the tachometer
enter the red zone, which indicates the maximum engine speed. ●
The engine may be overheating if the engine coolant temperature gauge is in the red
zone (H); or “Engine Coolant Temp High” or “Hybrid System Overheated” is shown
on the multi-information display. In this case, immediately stop the vehicle in a safe
place, and check the engine or hybrid system after it has cooled completely.
(  P. 600)

1774-1. Before driving
4
Driving
NX300h_U_OM78007U WA R N I N G
Observe the following precautions.
Failure to do so may result in death or serious injury. ■
When driving the vehicle ●
During normal driving, do not turn off the hybrid system. Turning the hybrid system off
while driving will not cause loss of steering or braking control, however, power assist
to the steering will be lost. This will make it more difficult to steer smoothly, so you
should pull over and stop the vehicle as soon as it is safe to do so.
In the event of an emergency, such as if it becomes impossible to stop the vehicle in
the normal way:  P. 5 5 7●
Use engine braking (downshift) to maintain a safe speed when driving down a steep
hill.
Using the brakes continuously may cause th e brakes to overheat and lose effective-
ness. (  P. 2 0 8 )●
Do not adjust the positions of the steering wh eel, the seat, or the inside or outside rear
view mirrors while driving.
Doing so may result in a loss of vehicle control. ●
Always check that all passengers’ arms, heads or other parts of their body are not
outside the vehicle. ●
AWD models: Do not drive the vehicle off-road.
This is not an AWD vehicle designed for of f-road driving. Proceed with all due cau-
tion if it becomes unavoidable to drive off-road. ●
Do not drive across a river or through other bodies of water.
This may cause electric/electronic components to short circuit, damage the hybrid
system or cause other serious damage to the vehicle. ●
Do not drive in excess of the speed limit. Ev en if the legal speed lim it permits it, do not
drive over 85 mph (140 km/h) unless your vehicle has high-speed capability tires.
Driving over 85 mph (140 km/h) may result in tire failure, loss of control and possible
injury. Be sure to consult a tire dealer to determine whether the tires on your vehicle
are high-speed capability tires or not before driving at such speeds.

1794-1. Before driving
4
Driving
NX300h_U_OM78007U WA R N I N G
Observe the following precautions.
Failure to do so may result in death or serious injury. ■
If you hear a squealing or scraping noise (brake pad wear limit indicators)
Have the brake pads checked and replaced by your Lexus dealer as soon as possible.
Rotor damage may result if the pads are not replaced when needed.
It is dangerous to drive the vehicle when the wear limits of the brake pads and/or those
of the brake discs are exceeded. ■
When the vehicle is stopped ●
Do not depress the accelerator pedal unnecessarily.
If the shift lever is in any position other than P or N, the vehicle may accelerate sud-
denly and unexpectedly, causing an accident. ●
In order to prevent accidents due to the vehicle rolling away, always keep depressing
the brake pedal while stopped with the “R EADY” indicator is illuminated, and apply
the parking brake as necessary. ●
If the vehicle is stopped on an incline, in order to prevent accidents caused by the
vehicle rolling forward or backward, always depress the brake pedal and securely
apply the parking brake as needed. ●
Avoid revving or racing the engine.
Running the engine at high speed while the vehicle is stopped may cause the exhaust
system to overheat, which could result in a fire if combustible material is nearby. ■
When the vehicle is parked ●
Do not leave glasses, cigarette lighters, sp ray cans, or soft drink cans in the vehicle
when it is in the sun.
Doing so may result in the following:
• Gas may leak from a cigarette lighter or spray can, and may lead to a fire.
• The temperature inside the vehicle may cause the plastic lenses and plastic mate-
rial of glasses to deform or crack.
• Soft drink cans may fracture, causing the contents to spray over the interior of the
vehicle, and may also cause a short circuit in the vehicle’s electrical components. ●
Do not leave cigarette lighters in the vehicle. If a cigarette lighter is in a place such as
the glove box or on the floor, it may be lit accidentally when luggage is loaded or the
seat is adjusted, causing a fire. ●
Do not attach adhesive discs to the windsh ield or windows. Do not place containers
such as air fresheners on the instrument panel or dashboard. Adhesive discs or con-
tainers may act as lenses, causing a fire in the vehicle. ●
Do not leave a door or window open if th e curved glass is coated with a metallized
film such as a silver-colored one. Reflected sunlight may cause the glass to act as a
lens, causing a fire. ●
Always shift the shift lever to P, apply the parking brake, stop the hybrid system and
lock the vehicle.
Do not leave the vehicle unattended wh ile the “READY” indicator is illuminated.●
Do not touch the exhaust pipes while the “R EADY” indicator is illuminated or imme-
diately after turning the hybrid system off.
Doing so may cause burns.

1934-1. Before driving
4
Driving
NX300h_U_OM78007U ●
Reversing with a trailer attached is di fficult and requires practice. Grip the
bottom of the steering wheel and move your hand to the left to move the
trailer to the left. Move your hand to the right to move the trailer to right. (This
is generally opposite to reversing without a trailer attached.) Avoid sharp or
prolonged turning. Have someone guid e you when reversing to reduce the
risk of an accident. ●
As stopping distance is increased when towing a trailer, vehicle-to vehicle dis-
tance should be increased. For each 10 mph (16 km/h) of speed, allow at least
one vehicle and trailer length. ●
Avoid sudden braking as you may skid, re sulting in the traile r jackknifing and a
loss of vehicle control. This is especially true on wet or slippery surfaces. ●
Avoid jerky starts or sudden acceleration. ●
Avoid jerky steering and sharp turns, and slow down before making turn. ●
Note that when making a turn, the traile r wheels will be closer than the vehicle
wheels to the inside of the turn. Comp ensate by making a wider than normal
turning radius. ●
Slow down before making a turn, in cross winds, on wet or slippery surfaces,
etc.
Increasing vehicle speed can destabilize the trailer. ●
Take care when passing other vehicles. Passing requires considerable dis-
tance. After passing a vehicle, do not forget the length of your trailer, and be
sure you have plenty of room before changing lanes. ●
To maintain engine braking efficiency and charging system performance
when using engine braking, do no t put the transmission in D. (  P. 2 0 8 )●
Instability happens more frequently when descending steep or long downhill
grades. Before descending, slow down and downshift. Do not make sudden
downshifts while descending steep or long downhill grades. ●
Avoid holding the brake pedal down too long or applying the brakes too fre-
quently. This could cause the brakes to overheat and result in reduced braking
efficiency. ●
Due to the added load of the trailer, yo ur vehicle’s engine may overheat on hot
days (at temperatures over 85  F [30  C]) when driving up a long or steep
grade. If the engine coolant temperat ure gauge indicates overheating, imme-
diately turn off the air cond itioning (if in use), pull your vehicle off the road and
stop in a safe spot. (  P. 600)

308 4-5. Using the driving support systems
NX300h_U_OM78007U ■
ECB operating sound
ECB operating sound may be hear d in the following cases, but it does not indicate that a
malfunction has occurred. ●
Operating sound heard from the engine compartment when the brake pedal is oper-
ated. ●
Motor sound of the brake system heard from the front part of the vehicle when the
driver’s door is opened. ●
Operating sound heard from the engine compartment when 1 or 2 minutes passed
after the stop of the hybrid system. ■
EPS operation sound
When the steering wheel is operated, a motor sound (whirring sound) may be heard.
This does not indicate a malfunction. ■
Reduced effectiveness of the EPS system
The effectiveness of the EPS system is reduced to prevent the system from overheating
when there is frequent steering input over an extended period of time. The steering
wheel may feel heavy as a result. Should this occur, refrain from excessive steering input
or stop the vehicle and turn the hybrid system off. The EPS system should return to nor-
mal within 10 minutes. ■
Automatic reactivation of TRAC and VSC systems
After turning the TRAC and VSC systems off, the systems will be automatically
re-enabled in the following situations: ●
When the power switch is turned off ●
If only the TRAC system is turned off, the TRAC will turn on when vehicle speed
increases
If both the TRAC and VSC systems are turn ed off, automatic re-enabling will not
occur when vehicl e speed increases.■
Operating conditions of hill-start assist control
When the following four conditions are met, the hill-start assist control will operate:●
The shift lever is in a position other than P or N (when starting off forward/backward on
an upward incline). ●
The vehicle is stopped. ●
The accelerator pedal is not depressed. ●
The parking brake is not engaged. ■
Automatic system cancelation of hill-start assist control
The hill-start assist control will turn off in any of the following situations: ●
The shift lever is moved to P or N. ●
The accelerator pedal is depressed. ●
The parking brake is engaged. ●
Approximately 2 seconds elapse after the brake pedal is released.

565
8
When trouble arises 8-2. Steps to take in an emergency
NX300h_U_OM78007UIf a warning light turns on or a warning buzzer
sounds Calmly perform the following actions if any of the warning lights comes on or
flashes. If a light comes on or flashes, bu t then goes off, this does not necessar-
ily indicate a malfunction in the system. However, if this continues to occur,
have the vehicle inspected by your Lexus dealer.
Warning light and warning buzzer list Warning light Warning light/Details/Actions(U.S.A.)
(Canada)
Brake system warning light
Indicates that:
• The brake fluid level is low; or
• The brake system is malfunctioning
 Immediately stop the vehicle in a safe place and contact your
Lexus dealer. Continuing to drive the vehicle may be dangerous.
* 1
Charging system warning light
Indicates a malfunction in the vehicle’s charging system
 Immediately stop the vehicle in a safe place and contact your
Lexus dealer. Continuing to drive the vehicle may be dangerous.
* 1
Low engine oil pressure warning light (warning buzzer)
Indicates that the engine oil pressure is too low
 Immediately stop the vehicle in a safe place and contact your
Lexus dealer. Continuing to drive the vehicle may be dangerous.
* 1
High coolant temperature warning light (warning buzzer)
Indicates that the engine is overheating
 Immediately stop the vehicle in a safe place. Continuing to drive
the vehicle may be dangerous.
Handling method (  P. 600)
Brake system warning light
Indicates a malfunction in:
• The regenerative braking system;
• The electronically controlled brake system; or
• The electric parking brake
 Have the vehicle inspected by your Lexus dealer immediately. (U.S.A.)
(Canada)
Malfunction indicator lamp
Indicates a malfunction in:
• The hybrid system;
• The electronic engine control system;
• The electronic throttle control system; or
• The emission control system
 Have the vehicle inspected by your Lexus dealer immediately.

574 8-2. Steps to take in an emergency
NX300h_U_OM78007U ■
If “Depress Brake When Vehicle Is Stopped Hybrid System May Overheat” is shown
Message is displayed when the accelerator pedal is depressed to maintain the vehicle
position when stopped on a upward slope, etc.
If this continues, the hybrid system may overheat.
Release the accelerator pedal and depress the brake pedal. ■
If “Oil Maintenance Required Soon” is shown
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 necessar y. After changing the engine oil, the oil
change system should be reset. (  P. 5 0 6 )■
If “Oil Maintenance Required” is shown
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 engine oil, and oil filt er by your Lexus dealer. After changing the
engine oil, the oil change system should be reset. (  P. 5 0 6 )■
If “See Owner’s Manual” is shown ●
If the following messages are shown, following the instru ctions, accordingly.
• “Engine Coolant Temp High” (  P. 6 0 0 )●
If the following messages are sh own, there may be a malfunction.
Immediately have the vehicle inspected by your Lexus dealer.
• “Hybrid System Malfunction”
•“Check Engine”
• “Hybrid Battery System Malfunction”
• “Accelerator System Malfunction”
• “Braking Power Low”
• “Smart Access System Malfunction” ●
If the following messages are sh own, there may be a malfunction.
Immediately stop the vehicle in a safe place and contact your Lexus dealer. Continuing
to drive the vehicle may be dangerous.
•“Low Oil Pressure”
• “Charging System Malfunction” ■
Warning buzzer
 P. 5 6 9
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 12-volt battery
may be deteriorating. Have the vehicle inspected by your Lexus dealer.

600 8-2. Steps to take in an emergency
NX300h_U_OM78007UIf your vehicle overheats ■
“Engine Coolant Temp High” is shown on the multi-information display
Stop the vehicle in a safe place and tu rn 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 (radiator) for any leaks.
Radiator
Cooling fans If a large amount of coolant leaks,
immediately contact your Lexus
dealer.The following may indicate that your vehicle is overheating. ●
The needle of the engine coolant temperature gauge (  P. 97) enters the
red zone, or a loss of hybrid system po wer is experienced. (For example, the
vehicle speed does not increase.) ●
“Engine Coolant Temp High” or “Hybrid System Overheated” is shown on
the multi-information display. ●
Steam comes out from under the hood.
Correction procedures 1
2
3
1
2

6038-2. Steps to take in an emergency
8
When trouble arises
NX300h_U_OM78007U Start the hybrid system and check if “Hybrid System Overheated” is shown
on the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer. WA R N I N G ■
To prevent an accident or injury when in specting 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 are
off.
When the hybrid system is operating, the gasoline engine may au tomatically start, or
the cooling fan may suddenly operate even if the gasoline engine stops. Do not touch
or approach rotating parts such as the fa n, which may lead to fingers or clothing
(especially a tie, a scarf or a muffler) ge tting caught, resulting in serious injury.●
Do not loosen the coolant reservoir cap while the hybrid system and radiator are hot.
High temperature steam or coolant could spray out.
NOTICE ■
When adding engine/power control unit coolant
Add coolant slowly after the hybrid system has cooled down sufficiently. Adding cool
coolant to a hot hybrid system too quickly can cause damage to the hybrid system. ■
To prevent damage to the cooling system
Observe the following precautions: ●
Avoid contaminating the coolant with foreign matter (such as sand or dust etc.). ●
Do not use any coolant additive. 6