2018 LEXUS NX300h check engine

3496-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U 6
Maintenance and care 1 Turn the power switch off.
2 Open the fuse box cover. 
Engine compartment: type A fuse
box Push the tab in and lift the lid off.

Engine compartment: type B fuse
box Push the tab in and lift the lid off.

Left side instrument panel
Remove the lid. 
Luggage compartment
3 Remove the fuse. Only type A fuse can be removed using the
pullout tool.
4 Check if the fuse is blown. Replace the blown fuse with a new fuse of
an appropriate amperage rating. The
amperage rating can be found on the fuse
box lid.Checking and replacing
fuses If any of the electrical components
do not operate, a fuse may have
blown. If this happens, check and
replace the fuses as necessary.
Checking and replacing fuses

354 6-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U Before replacing, check the wattage of
the light bulb to be replaced.
( → P.407) ■
Front side marker lights (bulb type)
1 Turn the bulb base counterclock-
wise.
2 Remove the light bulb.
3 When installing, reverse the steps
listed. ■
Front turn signal lights (bulb type)
1 Open the hood and remove the
cover for engine compartment
cover. ( → P.325, 328) 2 Remove the cover.
Push the center of the clip.
Remove the clip and cover.
3 Turn the bulb base counterclock-
wise.
4 Remove the light bulb.Replacing light bulbs
A
B

376 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U charged” ( → P.390).*
: Displays for about 6 seconds ■
If “Traction Battery Needs to be Pro-
tected Refrain From the Use of N Posi-
tion” is shown
This message may be displayed when the
shift lever is in N.
As the hybrid battery (traction battery) can-
not be charged when the shift lever is in N,
when the vehicle is to be stopped for a long
period of time, shift the shift lever to P. ■
If “Traction battery needs to be pro-
tected. Shift into P to restart.” is shown
Message is displayed when the remaining
charge for the hybrid battery (traction bat-
tery) is low, because vehicle has been
shifted 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 with out 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 Accelerator
Before Shifting” is shown
Message is displayed when the accelerator
pedal has been depressed and the shift
lever is in N. Releas e the accelerator pedal
and shift the shift lever to D, S or R. ■
If “Depress Brake When Vehicle Is
Stopped Hybrid Syst em 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, th e hybrid system may
overheat.
Release the accelerator pedal and depress
the brake pedal.
■
If “Front Camera Unavailable” or “Front
Camera Unavailable Remove Debris
On Windshield” is shown
The following systems may be suspended
until the problem shown in the message is resolved. ( → P.209, 367)●
PCS (Pre-Collision System) ●
LDA (Lane Departure Alert with steering
control) ●
Dynamic radar cruise control with full-
speed range ●
Adaptive High-beam System ●
Automatic High Beam ■
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 oi l maintenance data
has been reset.)
Check the engine oil, and change if neces-
sary. After changing th e engine oil, the oil
change system should be reset. ( → P.329)■
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 en gine oil, and oil fil-
ter by your Lexus dealer. After changing the
engine oil, the oil change system should be
reset. ( → P.329)■
If “See Owner’s Manual” is shown ●
If the following messages are shown, fol-
lowing the instruct ions, accordingly.
• “Engine Coolant Temp High” ( → P.394)
• “Aux Battery Low” ( → P.375)●
If the following messages are shown,
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 shown,
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.
• “Oil Pressure Low”

3837-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 7
When trouble arises 4 Lower the vehicle.
5 Firmly tighten each wheel nut two
or three times in the order shown in
the illustration.Tightening torque:
76 ft•lbf (103 N•m, 10.5 kgf•m)
6 Stow the flat tire, tire jack and all
tools. ■
The compact spare tire●
The compact spare tire is identified by the
label “TEMPORARY USE ONLY” on
the tire sidewall.
Use the compact spare tire temporarily,
and only in an emergency.
●
Make sure to check the tire inflation pres-
sure of the compact spare tire. ( → P.406)
■
After completing the tire change
The tire pressure warning system must be
reset. ( → P.341)
■
When using the compact spare tire
As the compact spare tire is not equipped
with a tire pressure warning valve and trans-
mitter, low inflation pressure of the spare
tire will not be indicated by the tire pressure warning system. Also, if you replace the
compact spare tire afte r the tire pressure
warning light comes on, the light remains
on. ■
When the compact spare tire is
equipped
The vehicle becomes lower when driving
with the compact spare tire compared to
when driving with standard tires. ■
If you have a flat front tire on a road cov-
ered with snow or ice
Install the compact spare tire on one of the
rear wheels of the vehicle. Perform the fol-
lowing steps and fit tire chains to the front
tires:
1 Replace a rear tire with the compact
spare tire.
2 Replace the flat front tire with the tire
removed from the rear of the vehicle.
3 Fit tire chains to the front tires.
WARNING■
When using the compact spare tire ●
Remember that the sp are tire provided
is specifically designed for use with
your vehicle. Do not use your spare
tire on another vehicle. ●
Do not use more than one spare tire
simultaneously.
●
Replace the spare tire with a standard
tire as soon as possible.
●
Avoid sudden acceleration, abrupt
steering, sudden br aking and shifting
operations that cause sudden engine
braking.

3957-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 7
When trouble arises coolant is unavailable.
6 Start the hybrid system and turn the
air conditioning system on to check
that the radiator cooling fans oper-
ate and to check for coolant leaks
from the radiator or hoses.The fans operate when the air conditioning
system is turned on immediately after a
cold start. Confirm that the fans are oper-
ating by checking the fan sound and air
flow. If it is difficult to check these, turn the
air conditioning system on and off repeat-
edly.
(The fans may not oper ate in freezing tem-
peratures.)
7 If the fans are not operating:
Stop the hybrid system immediately
and contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the
nearest Lexus dealer.
8 Check if “Engine Coolant Temp
High” is shown on the multi-infor-
mation 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. 
If “Hybrid System Overheated” is
shown on the multi-information dis-
play
1 Stop the vehicle in a safe place.
2 Stop the hybrid system and care-
fully lift the hood.
3 After the hybrid system has cooled
down, inspect the hoses and radia-
tor core (radiato r) for any leaks.
Radiator
Cooling fans If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4 The coolant level is satisfactory if it
is between the “FULL” and “LOW”
lines on the reservoir.
Reservoir
“FULL” line
“LOW” line
5 Add coolant if necessary. A
B
A
B
C

396 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U Water can be used in an emergency if
coolant is unavailable.
6 After stopping the hybrid system
and waiting for 5 minutes or more,
start the hybrid system again and
check if “Hybrid System Over-
heated” is shown on the multi-infor-
mation display.If the message does not disappear:
Stop the hybrid system and contact your
Lexus dealer.
If the message is not displayed:
The hybrid system temperature has
dropped and the vehicle may be driven
normally.
However, if the message appears again fre-
quently, contact your Lexus dealer.
WARNING■
To prevent an accident or injury 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
hood, do not open the hood until the
steam has subsided. The engine com-
partment may be very hot. ●
After the hybrid system has been
turned off, check that the “READY”
indicator is off. When the hybrid sys-
tem is operating, the gasoline engine
may automatically start, or the cooling
fan may suddenly operate even if the
gasoline engine stops. Do not touch or
approach rotating parts such as the
fan, which may lead to fingers or cloth-
ing (especially a tie, a scarf or a muf-
fler) getting caught, resulting in serious
injury. ●
Do not loosen the coolant reservoir
cap while the hybrid system and radia-
tor are hot.
High temperature steam or coolant
could spray out.
NOTICE■
When adding engine/power control
unit coolant
Add coolant slowly after the hybrid sys-
tem has cooled down sufficiently. Adding
cool coolant to a hot hybrid system too
quickly can cause dama ge to the hybrid
system. ■
To prevent damage to the cooling sys-
tem
Observe the following precautions: ●
Avoid contaminating the coolant with
foreign matter (such as sand or dust
etc.).
●
Do not use any coolant additive.

402 8-1. Specifications
LEXUS NX300h Owners Manu-
al_USA_OM78212U 
Rear
■
Oil capacity (Drain and refill [Reference*]) *
: The engine oil capacity is a reference quantity to be used when changing the engine oil.
Warm up the engine and turn off the hybrid system, wait more than 5 minutes, and check
the oil level on the dipstick.■
Engine oil selection
“Toyota Genuine Motor Oil” is used in
your Lexus vehicle. Use Lexus
approved “Toyota Genuine Motor Oil”
or equivalent to satisfy the following
grade and viscosity.
Oil grade: ILSAC GF-5 multigrade
engine oil
Recommended viscosity: SAE 0W-20
SAE 0W-20 is the best choice for
good fuel economy and good starting
in cold weather.
If SAE 0W-20 is not available, SAE 5W-20 oil may be used. However, it
must be replaced with SAE 0W-20 at
the next oil change.
Outside temperature
Oil viscosity (0W-20 is explained here Type Permanent magnet synchronous motor
Maximum output 50 kW
Maximum torque 103 ft•lbf (139 N•m, 14.2 kgf•m)
Hybrid battery (traction battery) Type Nickel-Metal hydride battery
Voltage 7.2 V/module
Capacity 6.5 Ah (3HR)
Quantity 34 modules
Overall voltage 244.8 V
Lubrication system With filter 4.6 qt. (4.4 L, 3.9 Imp.qt.)
Without filter 4.2 qt. (4.0 L, 3.5 Imp.qt.)
A

450 Alphabetical Index
LEXUS NX300h Owners Manu-
al_USA_OM78212U Accessory mode .........................................170
Compartment ............................................. 327
Engine switch................................................ 168
Hood................................................................ 325
How to start the hybrid system ........... 168
Identification number ................................ 401
If your vehicle has to be stopped in an
emergency ............................................... 358
Ignition switch (power switch) ............. 168
Overheating................................................. 394
Power switch ................................................ 168
Engine compartment cover .................... 328
Engine coolant
Capacity .........................................................403
Checking .......................................................330
Preparing and checking before winter
......................................................................... 257
Warning light ...............................................366
Engine coolant temperature gauge ........79
Engine oil
Capacity ......................................................... 402
Checking ....................................................... 328
Warning light ...............................................366
Engine oil maintenance data .................. 329
Engine switch ................................................. 168
EPS (Electronic Power Steering)
Function ..........................................................250
Warning light ............................................... 367
EV drive mode................................................. 171
EV indicator ...................................................... 62
Event data recorder (EDR) ............................7 F
Flat tire ..............................................................377
Tire pressure warning system ............ 338
Floor mats .......................................................... 24
Fluid
Brake ............................................................... 405
Transmission................................................ 404
Washer ........................................................... 332
Fog lights
Replacing light bulbs ................................353
Switch................................................................ 189
Front passenger occupant classification
system ................................................................ 41
Front passenger’s seat belt reminder light
.......................................................................... 369
Front seats ........................................................128
Adjustment ..................................................... 128
Cleaning ...........................................................317
Correct driving posture ............................ 25
Driving position memory .........................134
Head restraints..............................................137
Power easy access system .....................134
Seat heaters .................................................. 276
Seat position memory ...............................134
Front side marker lights
Light switch .................................................... 183
Replacing light bulbs ................................354
Wattage ..........................................................407
Front turn signal lights
Replacing light bulbs ................... 353, 354
Turn signal lever ...........................................176
Wattage ..........................................................407
Fuel
Capacity .......................................................... 401
Fuel gauge ........................................................ 79
Gas station information ......................... 460
Information ................................................... 408
Refueling.......................................................... 196
Type ................................................................... 401
Warning light .............................................. 369
Fuel filler door .................................................196