check engine LEXUS RX350 2016 Service Manual

578 7-3. Do-it-yourself maintenance
RX350_U_OM48E90U The coolant level is satisfactory if it is between the “FULL” and “LOW” lines on
the reservoir when the engine is cold.
Reservoir cap
“FULL” line
“LOW” line If the level is on or below the “LOW”
line, add coolant up to the “FULL”
line. (  P. 668)■
Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high qu ality ethylene glycol
based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life hybrid
organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mixt ure of 50% coolant and 50% deionized water.
(Minimum temperature: -31  F [-35  C])
Canada:
“Toyota Super Long Life Coolant” is a mixt ure of 55% coolant and 45% deionized water.
(Minimum temperature: -44  F [-42  C])
For more details about coolant, contact your Lexus dealer. ■
If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine coolant reservoir cap, drain cock and water
pump.
If you cannot find a leak, have your Lexus dealer test the cap and check for leaks in the
cooling system.Coolant 1
2
3
WA R N I N G ■
When the engine is hot
Do not remove the engine coolant reservoir cap and radiator cap.
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing serious injuries, such as burns.

5797-3. Do-it-yourself maintenance
7
Maintenance and care
RX350_U_OM48E90U Check the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of their condi-
tion, have your vehicle inspected by your Lexus dealer. NOTICE ■
When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of water and
antifreeze must be used to provide proper lubrication, corrosion protection and cool-
ing. Be sure to read the antifreeze or coolant label. ■
If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.
Radiator and condenser WA R N I N G ■
When the engine is hot
Do not touch the radiator or condenser as they may be hot and cause serious injuries,
such as burns.

5817-3. Do-it-yourself maintenance
7
Maintenance and care
RX350_U_OM48E90U Check the battery as follows. ■
Battery exterior Make sure that the 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 ■
Before recharging
When recharging, the battery produces hydrogen gas which is flammable and explosive.
Therefore, observe the following precautions before recharging: ●
If recharging with the 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 battery. ■
After recharging/reconnecting the battery ●
The engine may not start. Follow the pr ocedure below to initialize the system.
Shift the shift lever to P.
Open and close any of the doors.
Restart the engine.●
Unlocking the doors using the smart access system with push-button start may not be
possible immediately after reconnecting the battery. If this happens, use the wireless
remote control or the mechanical key to lock/unlock the doors. ●
Start the engine with the engine switch in ACCESSORY mode. The engine may not
start with the engine switch turned off. However, the engine will operate normally from
the second attempt. ●
The engine switch mode is recorded by the vehicle. If the battery is reconnected, the
vehicle will return the engine switch mode to the status it was in before the battery was
disconnected. Make sure to turn off the power before disconnect the battery. Take
extra care when connecting the battery if the engine switch mode prior to discharge is
unknown.
If the system will not start even after multiple attempts at all methods above, contact your
Lexus dealer.Battery 1
2
1
2
3

6057-3. Do-it-yourself maintenance
7
Maintenance and care
RX350_U_OM48E90U Turn the engine switch off.
Open the fuse box cover. 
Engine compartment
Push the tab in and lift the lid off. 
Driver’s side instrument panel
Remove the 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. 1
2

622 7-3. Do-it-yourself maintenance
RX350_U_OM48E90U ■
LED lights
The headlight low beams, headlight high beams, front turn signal lights (vehicles with tri-
ple-beam headlights), parking lights and dayt ime running lights, front fog lights, corner-
ing lights (if equipped), front side marker lights (vehicles with tr iple-beam headlights),
side turn signal lights, stop/t ail lights, rear turn signal lig ht (vehicles with triple-beam
headlights), rear side marker lights, high moun ted stoplight, license plate lights, and outer
foot lights consist of a number of LEDs. If an y of the LEDs has burned out, take your vehi-
cle to your Lexus dealer to have the light replaced. ■
Condensation build-up on the inside of a lens
Temporary condensation build-up on the inside of the headlight lens does not indicate a
malfunction. Contact your Lexus dealer for mo re information in the following situations:●
Large drops of water have built up on the inside of a lens.●
Water has built up inside a headlight. ■
When replacing light bulbs
 P. 6 0 6
WA R N I N G ■
To p r e v e n t i n j u r y
Before performing any light bulb replacement procedure, be sure to turn the engine
switch off. Failure to do so may result in burns from hot components or a part of your
body may get caught on an operating comp onent, possibly causing serious injury.■
Replacing light bulbs ●
Turn off the lights. Do not attempt to replace the bulb immediately after turning off the
lights.
The bulbs become very hot and may cause burns. ●
Do not touch the glass portion of the light bulb with bare hands. When it is unavoid-
able to hold the glass portion, use and ho ld with a clean dry cloth to avoid getting
moisture and oils on the bulb.
Also, if the bulb is scratched or dropped, it may blow out or crack.●
Fully install light bulbs and any parts used to secure them. Failure to do so may result
in heat damage, fire, or water entering the headlight unit. This may damage the head-
lights or cause condensation to build up on the lens.●
Do not attempt to repair or disassemble the light bulbs, connectors, electric circuits
or component parts.
Doing so may result in death or se rious injury due to electric shock.■
To prevent damage or fire ●
Make sure bulbs are fully seated and locked. ●
Check the wattage of the bulb before installin g to prevent heat damage.

6378-2. Steps to take in an emergency
8
When trouble arises
RX350_U_OM48E90U * : Driver's and front passenger' s seat belt warning buzzer:
The driver’s seat belt warning buzzer sounds to alert the driver that his or her seat belt
is not fastened. Once the engine switch is turned to IGNITION ON mode, the
buzzer sounds for 6 seconds. If the vehicl e reaches a speed of 12 mph (20 km/h), the
buzzer sounds once. If the seat belt is still unfastened afte r 24 seconds, the buzzer will
sound intermittently for 10 seconds. Then, if the seat belt is still unfastened, the buzzer
will sound in a different tone for 20 more seconds.
The front passenger’s seat belt warning buzzer sounds to alert the front passenger
that his or her seat belt is not fastened. The buzzer sounds once if the vehicle reaches
a speed of 12 mph (20 km/h). If the seat belt is still unfastened after 24 seconds, the
buzzer will sound intermittently for 10 seconds. Then, if the seat belt is still unfastened,
the buzzer will sound in a different tone for 20 more seconds. ■
SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact se nsors (rear), driver’s seat position sensor,
driver’s seat belt buckle swit ch, front passenger occupant classification system (ECU and
sensors), “AIR BAG ON” indicator light, “A IR BAG OFF” indicator light, front passen-
ger’s seat belt buckle switch, driver’s seat belt pretensioner, front passenger’s seat belt
pretensioner and force limiter, airbags, in terconnecting wiring and power sources.
(  P. 3 6 ) ■
Front passenger detection sensor, seat belt reminder and warning buzzer●
If luggage is placed on the front passenger seat, the front passenger detection sensor
may cause the warning light to flash and the warning buzzer to sound even if a passen-
ger is not sittin g in the seat.●
If a cushion is placed on th e seat, the sensor may not detect a passenger, and the warn-
ing light may not operate properly. ■
Electric power steering system warning light (warning buzzer)
When the battery charge becomes insufficie nt of the voltage te mporarily drops, the
electric power steering system warning light may come on and the warning buzzer may
sound. ■
If the malfunction indicator lamp comes on while driving
First check the following: ●
Is the fuel tank empty?
If it is, fill the fuel tank immediately. ●
Is the fuel tank cap loose?
If it is, tighten it securely.
The light will go off after several driving trips.
If the light does not go off even after severa l trips, contact your Lexus dealer as soon as
possible.

638 8-2. Steps to take in an emergency
RX350_U_OM48E90U ■
When the tire pressure warning light comes on
Inspect the tires to check if a tire is punctured.
If a tire is punctured:  P. 6 4 6
If none of the tires are punctured:
Turn the engine switch off then turn it to IGNITION ON mode. Check if the tire pressure
warning light comes on or blinks. 
If the tire pressure warning light comes on
After the temperature of the tires has lowere d sufficiently, check the inflation pressure
of each tire and adjust th em to the specified level.
If the warning light does not turn off even after several minutes have elapsed, check
that the inflation pressure of each tire is at the specified level and perform initialization.
(  P. 5 8 6 )
If the warning light does not turn off several minutes after the initia lization has been per-
formed, have the vehicle inspected by your Lexus dealer immediately. 
If the tire pressure warning light blinks for 1 minute then stays on
There may be a malfunction in the tire pressure warning system. Have the vehicle
inspected by your Lexus dealer immediately. ■
The tire pressure warning light may come on due to natural causes
The tire pressure warning light may come on due to natural causes such as natural air
leaks and tire inflation pressure changes caused by temperature. In this case, adjusting
the tire inflation pressure will turn off the warning light (after a few minutes). ■
When a tire is replaced with a spare tire
The compact spare tire is not equipped with a tire pressure warning valve and transmit-
ter. If a tire goes flat, the tire pressure warning light will not turn off even though the flat
tire has been replaced with the spare tire. Replace the spare tire with the repaired tire
and adjust the tire inflation pressure. The tire pressure warning light will go off after a few
minutes. ■
Conditions that the tire pressure warning system may not function properly
 P. 5 8 9 ■
Warning buzzer
In some cases, the buzzer may not be heard due to being in a noisy location or audio
sound. ■
Customization
Some functions can be customized. (  P. 6 9 9 )1
2

6438-2. Steps to take in an emergency
8
When trouble arises
RX350_U_OM48E90U Take the appropriate actions as in structed in the message displayed.
If any of the following messages are displa yed, also refer to this Owner’s Manual.■
If “Shift to P Before Exiting Vehicle” is shown
Message is displayed when the driver’s door is opened without turning the
engine switch off with the shift lever in any position other than P.
Shift the shift lever to P. ■
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 engine is started, increase the engine speed slightly and
maintain it at that spee d for approximately 5 minutes to recharge the battery.■
If “AWD System Overheated Switching to 2WD Mode” or “AWD System
Overheated 2WD Mode Engaged” is displayed (AWD models)
This message may be displayed when driving under extremely high load con-
ditions.
Drive the vehicle at low speeds or stop the vehicle in a safe place with the
engine running until the message is cleared.
If the message is not cleared, have the vehicle inspected by your Lexus dealer.■
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 for approximately one week after a new
electronic key has been registered.
If this message is displayed but you have 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 (if equipped) ●
AFS (Adaptive Front-lighting System) (if equipped)Other messages displayed on the multi-information display

644 8-2. Steps to take in an emergency
RX350_U_OM48E90U ■
If “Forward Camera System Unavailable” or “Forward Camera System
Unavailable Clean Windshield ” is displayed (if equipped)
The following systems may be suspended until the problem shown in the mes-
sage is resolved. ●
PCS (Pre-Collision System) ●
LKA (Lane-Keeping Assist) ●
LDA (Lane Departure Alert with steering control) ●
Dynamic radar cruise control with full-speed range ●
Dynamic radar cruise control ●
Automatic High Beam■
If “Oil Maintenance Required Soon” is shown
Indicates that the engine oil is schedule d to be changed. (The indicator will not
work properly unless the message has been reset.)
Check the engine oil, and change if ne cessary. After changing the engine oil,
the message should be reset. (  P. 5 7 7 )■
If “Oil Maintenance Required” is shown
Indicates that the engine oil should be changed. (After the engine oil is
changed and the message has been reset.)
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. 5 7 7 )■
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. Pl ease reset the message after the main-
tenance is performed. (  P. 565)
* : Refer to the separate “Scheduled Mainte nance” or “Owner’s Manual Supplement”
for the maintenance interval applicable to your vehicle.

6598-2. Steps to take in an emergency
8
When trouble arises
RX350_U_OM48E90U One of the following may be the cause of the problem: ●
One or both of the battery terminals may be disconnected. ●
The battery may be discharged. (  P. 6 6 5 )●
There may be a malfunction in the steering lock system. Contact your Lexus dealer if the problem cannot be repaired, or if repair procedures
are unknown.
When the engine does not start, the following steps can be used as an interim
measure to start the engine if the engine switch is functioning normally.
T urn the engine switch to IGNITION ON mode and check that the parking
brake is set. (  P. 221, 235)
Shift the shift lever to P.
Turn the engine switch to ACCESSORY mode.
Press and hold the engine switch for about 15 seconds while depressing the
brake pedal firmly.
Even if the engine can be started using the above steps, the system may be mal-
functioning. Have the vehicle inspected by your Lexus dealer.The starter motor does not turn ove r, the interior lights and headlights
do not turn on, or the horn does not sound.
Emergency start function 1
2
3
4