air condition Lexus GS300 2019 Service Manual

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GS350_300_OM_OM30G96U_(U)6-3. Do-it-yourself maintenance
NOTICE
■Repairing or replacing tires, wheels, tire
pressure warning valves, transmitters and
tire valve caps
●When removing or fitting the wheels, tires or the tire pressure warning valves and
transmitters, contact your Lexus dealer as the tire pressure warning valves and trans-
mitters may be damaged if not handled correctly.
●Make sure to install the tire valve caps. If the tire valve caps are not installed, water
could enter the tire pressure warning valves and the tire pressure warning valves
could be bound.
●When replacing tire valve caps, do not use tire valve caps other than those specified.
The cap may become stuck.
■To avoid damage to the tire pressu re warning valves and transmitters
When a tire is repaired with liquid sealants, the tire pressure warning valve and trans-
mitter may not operate properly. If a liquid sealant is used, contact your Lexus dealer or
other qualified service shop as soon as possible. Make sure to replace the tire pressure
warning valve and transmitter when replacing the tire. ( P. 396)
■Driving on rough roads
Take particular care when driving on roads with loose surfaces or potholes.
These conditions may cause lo sses in tire inflation pressure, reducing the cushioning
ability of the tires. In addition, driving on rough roads may cause damage to the tires
themselves, as well as the vehicle’s wheels and body.
■Low profile tires (except 225/50R17 tires)
Low profile tires may cause greater damage than usual to the tire wheel when sustain-
ing impact from the road surface. Ther efore, pay attention to the following:
●Be sure to use proper tire inflation pressu re. If tires are under-inflated, they may be
damaged more severely.
●Avoid potholes, uneven pavement, curbs an d other road hazards. Failure to do so
may lead to severe tire and wheel damage.
■If tire inflation pressure of ea ch tire becomes low while driving
Do not continue driving, or your tires and/or wheels may be ruined.

GS350_300_OM_OM30G96U_(U)
4076-3. Do-it-yourself maintenance
6
Maintenance and care
■Instructions for checking tire inflation pressure
When checking tire inflation pressure, observe the following:
●Check only when the tires are cold.
If your vehicle has been parked for at least 3 hours or has not been driven for more than
1 mile or 1.5 km, you will get an accurate cold tire inflation pressure reading.
●Always use a tire pressure gauge.
It is difficult to judge if a tire is properly inflated based only on its appearance.
●It is normal for the tire inflat ion pressure to be higher after driving as heat is generated
in the tire. Do not reduce tire inflation pressure after driving.
●Never exceed the vehicle capacity weight.
Passengers and luggage weight should be placed so that the vehicle is balanced.
WARNING
■Proper inflation is critical to save tire performance
Keep your tires properly inflated.
If the tires are not properly inflated, the following conditions may occur which could
lead to an accident resulting in death or serious injury:
●Excessive wear
●Uneven wear
●Poor handling
●Possibility of blowouts resu lting from overheated tires
●Air leaking from between tire and wheel
●Wheel deformation and/or tire damage
●Greater possibility of tire damage while driving (due to road hazards, expansion
joints, sharp edges in the road, etc.)
NOTICE
■When inspecting and adjust ing tire inflation pressure
Be sure to put the tire valve caps back on.
If a valve cap is not installed, dirt or moisture may get into the valve and cause an air
leak, resulting in decreased tire inflation pressure.

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GS350_300_OM_OM30G96U_(U)6-3. Do-it-yourself maintenance
Air conditioning filter
Turn the engine switch off.
Open the glove box. Lift up the side
with the stay, disconnect the stay
tabs and remove the partition by
pulling horizontally.
Press the tabs and remove the filter
cover.
Press the tabs and remove the filter
case.
The air conditioning filter must be ch
anged regularly to maintain air condi-
tioning efficiency.
Removal method
1
2
3
4

GS350_300_OM_OM30G96U_(U)
4116-3. Do-it-yourself maintenance
6
Maintenance and care
Remove the air conditioning filter
from the filter case and replace it
with a new one.
The “UP” marks shown on the filter
and the filter case sh ould be pointing up.
■Changing interval
Inspect and replace the air cond itioning filter according to the maintenance schedule. In
dusty areas or areas with heavy traffic fl ow, early replacement may be required. (For
scheduled maintenance informat ion, please refer to the “Owner’s Manual Supplement”
or “Scheduled Maintenance”.)
■If air flow from the vents decreases dramatically
The filter may be clogged. Check the filter and replace if necessary.
■Air conditioning filter with deodorizing function
When fragrances are placed in your vehicle, the deodorizing effect may become signifi-
cantly weakened in a short period.
When an air conditioning odor comes out cont inuously, replace the air conditioning filter.
5
NOTICE
■When using the air conditioning system
Make sure that a filter is always installed.
Using the air conditioning system without a filter may cause damage to the system.

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GS350_300_OM_OM30G96U_(U)
7
When trouble arises
7-2. Steps to take in an emergency
If you think something is wrong
●Fluid leaks under the vehicle.
(Water dripping from the air conditioning after use is normal.)
●Flat-looking tires or uneven tire wear
●Engine coolant temperature gauge needle continually points higher than nor-
mal.
●Changes in exhaust sound
●Excessive tire squeal when cornering
●Strange noises related to the suspension system
●Pinging or other noises related to the engine
●Engine missing, stumbling or running roughly
●Appreciable loss of power
●Vehicle pulls heavily to one side when braking
●Vehicle pulls heavily to one side when driving on a level road
●Loss of brake effectiveness, spongy feeling, pedal almost touches the floor
If you notice any of the following symptoms, your vehicle probably needs
adjustment or repair. Contact your Lexus dealer as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms

4417-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
7
When trouble arises
■SRS warning light
This warning light system monitors the airbag sensor assembly, front impact sensors, side
impact sensors (front door), side impact se nsors (front), side impact sensors (rear),
driver’s seat position sensor, driver’s seat belt buckle switch, front passenger occupant
classification system, “AIR BAG ON” indicat or light, “AIR BAG OFF” indicator light,
front passenger’s seat belt buckle switch, seat belt pretensioner assemblies, airbags,
interconnecting wiring and power sources. (P. 43)
■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 passenger
is not sitting in the seat.
■If the malfunction indicator lamp comes on while driving
First check the following:
●Is the fuel tank empty?
If it is, fill the fu el 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.
■Electric power steering system warning light (warning buzzer)
When the battery charge becomes insufficien t or the voltage temporarily drops, the
electric power steering system warning li ght may come on and the warning buzzer may
sound.
■When the tire pressure warning light comes on
Check the tire inflation pressure and adjust to the appropriate level. Initializing the tire
pressure warning system will not turn off the tire pressure warning light.
■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 caus ed 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.
■Conditions that the tire pressure wa rning system may not function properly
 P. 400
■If the tire pressure warning light freque ntly comes on after blinking for 1 minute
If the tire pressure warning light frequently comes on after blinking for 1 minute when the
engine switch is turned to IGNITION ON mo de, have it checked by your Lexus dealer.

4687-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
Warning messageDetails/Actions
(If equipped)
Indicates that the PCS (Pre-Collision System) is tempo-
rarily unavailable
 When conditions improve, the system resumes
operation. If this item is displayed continuously, have
the vehicle inspected by your Lexus dealer.
Air conditioning, heater and other operations are tem-
porarily limited due to high power consumption
 Turn off unnecessary electronic equipment to
reduce power consumption.
Please wait until the power supply returns to nor-
mal.
If this item is frequently displayed, have the vehicle
inspected at your Lexus dealer immediately.
(If equipped)
Indicates that part of th e PCS (Pre-Collision System)
sensor is dirty, covered with ice, etc. A buzzer also sounds.
 Remove any dirt, ice, etc.
(Flashes)
(Flashes)
(Flashes)

4997-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
7
When trouble arises
WARNING
■Driving to spread th e liquid sealant evenly
●Drive the vehicle carefully at a low speed. Be especially careful when turning and cor-
nering.
●If the vehicle does not drive straight or you feel a pull through the steering wheel, stop
the vehicle and check the following:
• Tire condition. The tire may have separated from the wheel.
• Tire inflation pressure. If tire inflation pressure is 19 psi (130 kPa, 1.3 kgf/cm
2 or
bar) or less, the tire may be severely damaged.
NOTICE
■When performing an emergency repair
●Perform the emergency repair without removi ng the nail or screw that has punctured
the tread of the tire. If the object that has punctured the tire is removed, repair by the
emergency tire puncture repair kit may not be possible.
●The repair kit is not waterproof. Make sure that the repair kit is not exposed to water,
such as when it is be ing used in the rain.
●Do not put the repair kit directly onto dusty ground such as sand at the side of the
road. If the repair kit vacuums up dust etc., a malfunction may occur.
■Handling the emergency tire puncture repair kit
●The repair kit power source should be 12 V DC suitable for vehicle use. Do not con-
nect the repair kit to any other source.
●If gasoline splatters on the repair kit, the repair kit may deteriorate. Take care not to
allow gasoline to contact it.
●Store the emergency tire puncture repair kit in the trunk.
The kit may be thrown around during sudden braking and so forth, damaging the kit.
●Store the repair kit in the tr unk out of reach of children.
●Do not disassemble or modify the repair kit. Do not subject parts such as the air pres-
sure indicator to impacts. This may cause a malfunction.
■To avoid damage to the tire pressu re warning valves and transmitters
When a tire is repaired with liquid sealants, the tire pressure warning valve and trans-
mitter may not operate properly. If a liquid sealant is used, contact your Lexus dealer or
other qualified service shop as soon as possible. Make sure to replace the tire pressure
warning valve and transmitter when replacing the tire. ( P. 396)

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GS350_300_OM_OM30G96U_(U)7-2. Steps to take in an emergency
If your vehicle overheats
●The needle of the engine coolant temperature gauge (
P. 92, 98) enters the
red zone or a loss of engine power is experienced. (For example, the vehicle
speed does not increase.)
●“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” is
shown on the multi-information display.
●Steam is coming from under the hood.
Stop the vehicle in a safe place and tu rn off the air conditioning system, and
then stop the engine.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the engine has cooled down sufficiently, inspect the hoses and cooling
core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact your Lexus
dealer.
The following may indicate that your vehicle is overheating.
Correction procedures
1
2
3
1
2

5147-2. Steps to take in an emergency
GS350_300_OM_OM30G96U_(U)
Add coolant if necessary.
Water can be used in an emergency if coolant is unavailable.
Start the engine and turn the air conditio ning system on to check that the radi-
ator 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, turn the air conditioning system on and off repeatedly.
(The fans may not operate in freezing temperatures.)
If the fans are not operating:
Stop the engine immediately an d contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the nearest Lexus dealer.
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GS350GS F
GS300
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