
5137-3. Do-it-yourself maintenance
7
Maintenance and care
NX300h_U_OM78007U Make sure that the 12-volt battery terminals are not corroded and that there are
no loose connections, cracks, or loose clamps.
Te r m i n a l s
Hold-down clamp
Insert the left side auxiliary box.
Push up center position
Insert
Press ■
Before recharging
When recharging, the 12-volt battery produces hydrogen gas which is flammable and
explosive. Therefore, observe the following precautions before recharging: ●
If recharging with the 12-volt battery installed on the vehicle, be sure to disconnect the
ground cable. ●
Make sure the power switch on the charger is off when connecting and disconnecting
the charger cables to the 12-volt battery. ■
After recharging/reconnecting the 12-volt battery ●
The hybrid system may not start. Follow the procedure below to initialize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the hybrid system.●
Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the 12-volt battery. If this happens, use the
wireless remote control or the mech anical key to lock/unlock the doors.●
Start the hybrid system with the power switch in ACCESSORY mode. The hybrid sys-
tem may not start with the power switch turned off. However, the hybrid system will
operate normally from the second attempt.Exterior 1
2
Installing the 12-volt battery maintenance cover 1
2
3
1
2
3

5157-3. Do-it-yourself maintenance
7
Maintenance and care
NX300h_U_OM78007U WA R N I N G ■
When handling the 12-volt battery
P. 5 9 9 ■
When disconnecting the 12-volt battery
NOTICE ■
When recharging the 12-volt battery
Never recharge the 12-volt battery while the hybrid system is operating. Also, be sure
all accessories are turned off.Do not disconnect the negative (-) terminal on
the body side as shown. The disconnected neg-
ative (-) terminal may to uch the positive (+) ter-
minal, which may cause a short and result in
death or serious injury.

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.

5738-2. Steps to take in an emergency
8
When trouble arises
NX300h_U_OM78007U * : A buzzer sounds the first time a message is shown on the multi-information display. ■
System warning lights
The master warning light does not come on or flash in the following cases. Instead, a sep-
arate system warning light will come on al ong with a message shown on the multi-infor-
mation display. ●
Malfunction of the ABS
The ABS warning light comes on. ( P. 566)●
Malfunction of th e charging system
The charging system warning light comes on. ( P. 565)■
If “Hybrid System Overheated Reduced Output Power” is shown
This message may be displayed when driv ing under severe operating conditions.
(For example, when drivin g up a long steep hill.)
Handling method: P. 6 0 0■
If “Cooling Performance of The Hybrid Battery Is Low” is shown
The filter may be clogged, or the air intake vents or ducts may be blocked. Have the vehi-
cle inspected by your Lexus dealer. ■
If “Hybrid Battery Low Shift Out of N to Recharge” is shown
Message is displayed when the remaining charge for the hybrid battery (traction battery)
is low.
As the hybrid battery (traction battery) can not be charged when the shift lever is in N,
when stopped for long periods of time shift the shift lever to P.■
If “Hybrid Battery Low Hybrid System St opped Shift to P and Restart” is shown
Message is displayed when the remaining charge for the hybrid battery (traction battery)
is low, because vehicle has been sh ifted N for a long period of time.
When operating the vehicle, restart the hybrid system. ■
If “Shift to P Before Exiting Vehicle” is shown
Message is displayed when the driver’s door is opened without turning the power switch
to OFF with the shift lever in any position other than P.
Shift the shift lever to P. ■
If “Shift Is in N Release Accele rator Before Shifting” is shown
Message is displayed when the accelerator pe dal has been depressed and the shift lever
is in N. Release the accelerator peda l and shift the shift lever to D or R.Comes
on Does not sound Indicates a condition, such as malfunc-
tion of electrical components, their
condition, or indicates the need for
maintenance
Flashes Does not sound Indicates a situation, such as when an
operation has been performed incor-
rectly, or indicates how to perform an
operation correctlySystem
warning
light Wa r n i n g b u z z e r
* Wa r n i n g

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.

5978-2. Steps to take in an emergency
8
When trouble arises
NX300h_U_OM78007U 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 second vehicle and start the hybrid system
of your vehicle by turning the power switch to ON mode.
Make sure the “READY” indicator comes on. If the indicator light does not
come on, contact your Lexus dealer.
Once the hybrid system has started, remove the jumper cables in the exact
reverse order from which they were connected.
Close the exclusive jump starting terminal cover, and reinstall the fuse box
cover to its original position.
Once the hybrid system starts, have th e vehicle inspected at your Lexus dealer
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 the
hybrid system may be unable to start. (The 12-volt battery recharges automatically while
the hybrid system is operating.) ■
When the 12-volt battery is removed or discharged ●
In some cases, it may not be possible to unlock the doors using the smart access system
with push-button start when the 12-volt battery is discharged. 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 mode it was in before the 12-volt battery was
discharged. Before disconnecting the 12-volt 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. ●
The power back door must be initialized. ( P. 1 3 4 )●
Make sure that the key is not inside the vehicle when recharging or replacing the
12-volt battery. The key may be locked in the vehicle if the alarm is activated. ( P. 88)5
6
7
8
9
10

5998-2. Steps to take in an emergency
8
When trouble arises
NX300h_U_OM78007U WA R N I N G ■
12-volt battery precautions
The 12-volt battery contains poisonous and corrosive acidic electrolyte, while related
parts contain lead and lead compounds. Ob serve the following precautions when han-
dling the 12-volt battery: ●
When working with the 12-volt battery, alwa ys wear safety glasses and take care not
to allow any battery fluids (acid) to come in to contact with skin, clothing or the vehicle
body. ●
Do not lean over the 12-volt battery. ●
In the event that battery fluid comes into contact with the skin or eyes, immediately
wash the affected area with water and seek medical attention.
Place a wet sponge or cloth over the affected area until medical attention can be
received. ●
Always wash your hands after handling the 12-volt battery support, terminals, and
other battery-related parts. ●
Do not allow children near the 12-volt battery. ■
After recharging the 12-volt battery
Have the 12-volt battery inspected at your Lexus dealer as soon as possible.
If the 12-volt battery is deteriorating, continued use may cause the 12-volt battery to
emit a malodorous gas, which may be de trimental to the health of passengers.■
When exchanging the 12-volt battery
After exchanging, securely attach the exha ust hose and exhaust hole plug to the
exhaust hole of the exchanged 12-volt battery. If not properly installed, gases (hydro-
gen) may leak into the vehicle interior, and th ere is the possible danger of the gas ignit-
ing and exploding.
NOTICE ■
When handling jumper cables
When connecting the jumper cables, ensure th at they do not become entangled in the
cooling fans or belt. ■
To prevent damaging the vehicle
The exclusive jump starting terminal is to be used when charging the 12-volt battery
from another vehicle in an emergency. It ca nnot be used to jump start another vehicle.

6139-1. Specifications
9
Vehicle specifications
NX300h_U_OM78007U * : The coolant capacity is the quantity of reference.
If replacement is necessary, contact your Lexus dealer.Cooling system Capacity
* Gasoline
engine
Vehicles without towing package
7.7 qt. (7.3 L, 6.4 Imp.qt.)
Vehicles with towing package
7.1 qt. (6.7 L, 5.9 Imp.qt.)
Po w e r
control unit 3.3 qt. (3.1 L, 2.7 Imp.qt.)
Coolant type Use either of the following:
• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based
non-silicate, non-amine, non-nitrite, and non-
borate coolant with long-life hybrid organic
acid technology
Do not use plain water alone.
Ignition system (spark plug) Make DENSO FK16HR-A8
Gap 0.03 in. (0.8 mm)
NOTICE ■
Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Electrical system 12-volt battery
Open voltage at 68 F (20 C): 12.6 V or higher: Fully charged
12.2 — 12.4 V: Half charged
12.0 V or lower: Discharged
(Voltage is checked 20 minutes after the hybrid
system and all lights are turned off.)
Charging rates 5 A max.