check engine LEXUS RX450h 2018 Owner's Manual

670 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
If “Shift Is in N Release Accele rator Before Shifting” is shown
Message is displayed when the accele rator pedal has been depressed and
the shift lever is in N. Release the accelerator pedal and shift the shift lever to
D or R. ■
If “Depress Brake when Vehicle Is Stopped Hybrid System May Overheat”
is shown
Message is displayed when the accelerato r 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 “Power Turned Off to Save Battery” is displayed
This message is displayed when the power was cut off due to the automatic
power off function.
The next time the hybrid system is star ted, increase the engine speed slightly
and maintain it at that speed for appr oximately 5 minutes to recharge the 12-
volt battery. ■
If “A New Key has been Registered Contact Your Dealer for Details” is dis-
played
This message will be displayed each time the driver's door is opened when the
doors are unlocked from the outside fo r approximately one week after a new
electronic key has been registered.
If this message is displayed but you ha ve not had a new electronic key regis-
tered, ask your Lexus dealer to check if an unknown electronic key (other than
those in your possession) has been registered. ■
When “Headlight System Malfunctio n Visit Your Dealer” is displayed
The following systems may be malfunct ioning. Have the vehicle inspected by
your Lexus dealer immediately. ●
The LED headlight system ●
The automatic headlight leveling system ●
Automatic High Beam ●
AFS (Adaptive Front-lighting System) (if equipped)

6718-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85U■
If “Forward Camera System Unavailable” or “Forward Camera System
Unavailable Clean Windshield” is displayed
The following systems may be suspended until the problem shown in the mes-
sage is resolved. ( → P. 296)●
PCS (Pre-Collision System) ●
LKA (Lane-Keeping Assist) ●
Dynamic radar cruise control with full-speed range ●
Automatic High Beam■
If “Oil Maintenance Required Soon” is shown
Indicates that the engine oil is scheduled to be changed.
Check the engine oil, and change if necessary. After changing the engine oil,
the message should be reset. ( → P. 600)■
If “Oil Maintenance Required” is shown
Indicates that the engine oil should be changed.
Check and change the engine oil, and o il filter by your Lexus dealer. After
changing the engine oil, the message should be reset. ( → P. 600)■
If “Maintenance Required Soon” is displayed (U.S.A. only)
Indicates that all maintenance according to the driven distance on the mainte-
nance schedule
* should be performed soon.
Comes on approximately 4500 miles (7200 km) after the message has been
reset.
If necessary, perform maintenance. Plea se reset the message after the main-
tenance is performed. ( → P. 588)
* : Refer to the separate “Scheduled Mainte nance” or “Owner’s Manual Supplement”
for the maintenance interval applicable to your vehicle.

7038-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UAdd 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 air conditioning system is turned on immediately after a
cold start. Confirm that the fans are operating 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 fans may not operate in freezing temperatures.)
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.
Check if “Engine Coolant Temp High Stop in a Safe Place See Owner’s
Manual” 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. 5
6
7
8

7058-2. Steps to take in an emergency
8
When trouble arises
RX450h_RX450hL _U_OM48F85UStart the hybrid system and check if “Hybrid System Overheated Reduced
Output Power” 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. 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 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 is operating, the gasoline engine may automatically start, or
the cooling fans may suddenly operate even if the gasoline engine stops. Do not
touch or approach rotating parts such as th e fans, which may lead to fingers or cloth-
ing (especially a tie, a scarf or a muffler) getting caught, resulting in serious injury.●
Do not loosen the radiator cap and the coolant reservoir caps wh ile 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 foreig n matter (such as sand or dust etc.).●
Do not use any coolant additive. 6

7139-1. Specifications
9
Vehicle specifications
RX450h_RX450hL _U_OM48F85U* : 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.Hybrid battery (traction battery) Type Nickel-Metal hydride battery
Voltage 9.6 V/module
Capacity 6.5 Ah (3HR)
Quantity 30 modules
Overall voltage 288 V
Lubrication system Oil capacity
(Drain and refill — reference
* )
With filter 
Vehicles with towing package
5.8 qt. (5.5 L, 4.8 Imp. qt.) 
Vehicles without towing package
5.7 qt. (5.4 L, 4.8 Imp. qt.)
Without filter 5.6 qt. (5.3 L, 4.7 Imp. qt.)

7159-1. Specifications
9
Vehicle specifications
RX450h_RX450hL _U_OM48F85U* : The coolant capacity is a reference quantity.
If replacement is necessary, contact your Lexus dealer.Cooling system Capacity
* Gasoline
engine 
RX450h
10.7 qt. (10.1 L, 8.9 Imp. qt.) 
RX450hL
13.2 qt. (12.5 L, 11 Imp. qt.)
Power control
unit 2.0 qt. (1.9 L, 1.7 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 FK20HBR8
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.

776 Alphabetical index
RX450h_RX450hL _U_OM48F85UEmergency, in case of
If a warning buzzer sounds.......... 660
If a warning light turns on.............. 660
If a warning message is
displayed.............................................667
If the 12-volt battery is
discharged ........................................ 695
If the electronic key does not
operate properly.............................692
If the hybrid system will
not start ............................................... 690
If you have a flat tire ..........................673
If you lose your keys ................ 133, 135
If you think something is
wrong .................................................. 659
If your vehicle becomes
stuck ..................................................... 706
If your vehicle has to
be stopped in an
emergency........................................ 653
If your vehicle needs to be
towed................................................... 654
If your vehicle overheats ................702
Energy monitor ....................................... 124 Engine
ACCESSORY mode ..................... 240
Compartment ..................................... 597
Engine switch ...................................... 239
Hood........................................................595
How to start the hybrid
system .................................................. 239
Identification number......................... 712
If your vehicle has to be
stopped in an emergency..........653
Ignition switch (power switch) .... 239
Overheating......................................... 702
Power switch ....................................... 239
Engine coolant
Capacity................................................... 715
Checking ................................................ 601
Preparing and checking
before winter ....................................390
Engine coolant temperature
gauge .........................................................96
Engine oil
Capacity................................................... 713
Checking .............................................. 598
Preparing and checking
before winter ....................................390
Engine oil maintenance data ........... 600
Engine switch ......................................... 239
Enhanced VSC ..................................... 382
EPS
(Electronic Power Steering) ........ 383
Warning light .........................................661
EV drive mode .......................................244
EV indicator ............................................... 76
Event data recorder (EDR).....................11