2018 LEXUS NX300h engine overheat

394 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 
“Engine Coolant Temp High” is
shown on the multi-information dis-
play
1 Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the hybrid system.
2 If you see steam:
Carefully lift the hood after the
steam subsides.
If you do not see steam:
Carefully lift the hood.
3 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, 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. Water can be used in an emergency if If your vehicle overheats The following may indicate that
your vehicle is overheating.
 The needle of the engine coolant
temperature gauge ( → P.79)
enters the red zone, or a loss of
hybrid system power is experi-
enced. (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 A
B
A
B
C

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

449What to do if... (Troubleshooting)
LEXUS NX300h Owners Manu-
al_USA_OM78212U Alphabetical Index
449Defogger
Outside rear view mirrors .................... 269
Rear window ................................................ 269
Windshield .................................................... 269
Differential ...................................................... 405
Dimension ......................................................400
Dinghy towing................................................. 167
Display
Drive information .......................................... 86
Dynamic radar cruise control with full-
speed range ................................................ 217
Energy monitor.............................................. 94
LDA (Lane Departure Alert with steering
control) ..........................................................210
Multi-information display .......................... 85
Warning messages .................................. 375
Do-it-yourself maintenance .................... 324
Doors
Automatic door lock ing and unlocking
system ........................................................... 109
Back door......................................................... 110
Door glasses .................................................. 144
Door lock........................................................ 106
Outside rear view mirrors ...................... 142
Rear door child-protectors ................... 109
Side doors ...................................................... 106
Drive information ........................................... 86
Drive-start control ............................... 151, 173
Driver’s seat belt remi nder light ............ 369
Driver’s seat position memory .................134
Driving
Break-in tips .................................................... 151
Correct posture ............................................ 25
Driving mode select switch .................. 249
Hybrid vehicle driving tips .................... 255
Procedures .................................................... 150
Winter drive tips......................................... 257
Driving position memory............................134
Memory recall function ............................135
Dynamic radar cruise control with full-
speed range
Function ............................................................ 217 Warning message ..................................... 374 E
E-Four .............................................................. 250
ECB (Electronically Controlled Brake Sys-
tem) ................................................................ 250
Eco mode........................................................ 249
EDR (Event data recorder) ............................7
Electric motor
Location ...............................................................61
Specification .................................................. 401
Electric Power Steering (EPS)
Function ......................................................... 250
Warning light ............................................... 367
Electronic key
Battery-saving function.............................123
If the electronic key does not operate
properly .......................................................387
Replacing the battery ............................... 347
Electronically Controlled Brake System
(ECB) ............................................................ 250
Emergency flashers ....................................358
Emergency, in case of
If a warning buzzer sounds.................. 365
If a warning light turns on...................... 365
If a warning message is displayed ..... 374
If the 12-volt battery is discharged ... 390
If the electronic key does not operate
properly .......................................................387
If the fuel filler do or cannot be opened
..........................................................................387
If the hybrid system will not start ....... 385
If you have a flat tire .................................. 377
If you lose your keys ....................... 103, 105
If you think something is wrong..........363
If your vehicle becomes stuck ............. 397
If your vehicle has to be stopped in an
emergency ................................................ 358
If your vehicle needs to be towed .... 360
If your vehicle overheats ........................394
Energy monitor ............................................... 94
Engine

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

451What to do if... (Troubleshooting)
LEXUS NX300h Owners Manu-
al_USA_OM78212U Alphabetical Index
451Refueling ..........................................................196
When the fuel filler door cannot be
opened ........................................................ 387
Fuses ................................................................. 349 G
Garage door opener ................................. 298
Gas station information ............................ 460
Gauges ................................................................79
Glove box ....................................................... 282
Glove box light ............................................. 282
Grocery bag hooks .................................... 285 H
Head restraints ............................................... 137
Head-up display.............................................. 90
Headlights ....................................................... 183
Automatic headlight leveling ................ 184
Automatic High Beam ............................. 186
Light switch .................................................... 183
Replacing light bulbs................................ 353
Heated steering wheel ...............................276
Heaters
Automatic air conditioning system ...268
Heated steering wheel............................ 275
Outside rear view mirrors .................... 269
Seat heaters .................................................. 275
High mounted stoplight
Replacing light bulb..................................353
Hill-start assist control ............................... 250
Hood ................................................................. 325
Warning message........................... 107, 374
Hooks
Cargo hooks................................................ 284
Retaining hooks (floor mat)......................24
Horn ................................................................... 140
Hybrid battery (traction battery)
Location............................................................. 64
Specification ................................................. 402
Hybrid battery air vent ................................. 66
Hybrid system .................................................... 61 Emergency shut off system...................... 67
Energy monitor/consumption screen 94
EV drive mode............................................... 171
High voltage components ....................... 64
Hybrid System Indicator ........................... 82
Hybrid system precautions...................... 64
Hybrid vehicle driving tips ....................255
If the hybrid system will not start ....... 385
Overheating .................................................394
Power switch................................................. 168
Regenerative braking ................................. 62
Starting the hybrid system ...................... 168
Vehicle proximity noti fication system. 63
Hybrid System Indicator.............................. 82
Hybrid transmission...................................... 173
I
I/M test ............................................................ 322
Identification
Engine............................................................... 401
Vehicle ........................................................... 400
Ignition switch (Power switch) ................ 168
Illuminated entry system ........................... 278
Immobilizer system........................................ 69
Indicators ............................................................74
Initialization
Engine oil maintenance data................329
Items to initialize ......................................... 429
Tire pressure warning system ...............341
Inside rear view mirror ............................... 140
Instrument panel light control ................... 84
Interior lights.................................................. 278
Intuitive parking assist
Function .......................................................... 227
Warning message ..................................... 229

453What to do if... (Troubleshooting)
LEXUS NX300h Owners Manu-
al_USA_OM78212U Alphabetical Index
453M
Maintenance
Do-it-yourself maintenance ................. 324
General maintenance ...............................319
Maintenance data..................................... 400
Maintenance requirements ....................319
Malfunction indicator lamp ..................... 366
Meter
Head-up display ........................................... 90
Indicators ...........................................................74
Instrument panel light control ................ 84
Meters ................................................................ 79
Multi-information display .......................... 85
Warning lights .............................................365
Warning messages .................................. 374
Micro dust and pollen filter ..................... 273
Microphone ................................................... 306
Mirrors
Inside rear view mirror............................. 140
Outside rear view mirror defoggers269
Outside rear view mirrors ...................... 142
Vanity mirrors..............................................288
Moon roof
Jam protection function............................ 147
Operation........................................................146
Warning message...........................148, 374
Multi-information display
Drive information .......................................... 86
Dynamic radar cruise control with full-
speed range ................................................ 217
Energy monitor.............................................. 94
Language....................................................... 422
LDA (Lane Departure Alert with steering
control) ..........................................................210
Warning messages .................................. 374
N
Noise from under vehicle ...............................6 O
Odometer ..........................................................79
Oil
Engine oil........................................................402
Rear differential oil......... .......... ........... ...... 405
Opener
Back door ......................................................... 113
Fuel filler door ............................................... 196
Hood ................................................................325
Outside rear view mirrors ......................... 142
Adjusting and folding.................................142
Blind Spot Monitor (BSM)......................241
Linked mirror functi on when reversing
............................................................................142
Mirror position memory ...........................134
Outside rear view mirror defoggers269
Outside temperature display .....................79
Overheating .................................................. 394
P
Paddle shift switches .................................... 175
Panic mode ..................................................... 104
Parking brake
Operation ........................................................ 177
Parking brake engaged warning buzzer/
message ........................................................ 177
Warning light .............................................. 369
Parking lights
Light switch .................................................... 183
Replacing light bulb ..................................353
Parking Support Brake fu nction (for static
objects) ......................................................... 232
Indicator............................................................. 75
Warning light .............................................. 368
Warning messages...................................238
PCS (Pre-Collision System)
Function ..........................................................203
PCS switch................................................... 205
Warning light ............................................... 367
Warning message ..................................... 374
Personal lights............................................... 278