Lexus is300 2021, Service Manual

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6-3. Do-it-yourself maintenance
■
Routine tire inflation pressure checks
The tire pressure warning system does not
replace routine tire inflation pressure
checks. Make sure to check tire inflation
pressure as part of your routine of daily
vehicle checks.
■ Tire inflation pressure
● It may take a few minutes to display the
tire inflation pressure after the engine
switch is turned to IGNITION ON mode.
It may also take a few minutes to display
the tire inflation pressure after inflation
pressure has been adjusted.
● Tire inflation pressure changes with tem-
perature. The displayed values may also
be different from the values measured
using a tire pressure gauge.
■
Situations in which the tire pressure
warning system may not operate prop-
erly
● In the following cases, the tire pressure
warning system may not operate prop-
erly.
• If non-genuine Lexus wheels are used.
• If a tire has been replaced with a tire that
is not an OE (Original Equipment) tire.
• If a tire has been replaced with a tire that
is not of the specified size.
• If tire chains, etc. are installed.
• An auxiliary-supported run-flat tire is
equipped.
• If a window tint that affects the radio wave
signals is installed.
• If there is a lot of snow or ice on the vehi-
cle, particularly around the wheels or
wheel housings.
• If the tire inflation pressure is extremely
higher than the specified level.
• If tires not equipped with tire pressure
warning valves and transmitters are used.
• If the ID code on the tire pressure warn-
ing valves and transmitters is not regis-
tered in the tire pressure warning
computer.
● Performance may be affected in the fol-
lowing situations.
• When driving near a TV tower, electric
power plant, gas station, radio station,
large display, airport or other facility that
generates strong radio waves or electri-
cal noise
• When carrying a portable radio, cellular
phone, cordless phone or other wireless
communication device
If tire position information is not correctly
displayed due to the radio wave conditions,
the display may be corrected by driving and
changing the radio wave conditions.
● When the vehicle is parked, the time
taken for the warning to start or go off
could be extended.
● When tire inflation pressure declines rap-
idly for example when a tire has burst, the
warning may not function.
■
Warning performance of the tire pres-
sure warning system
The warning of the tire pressure warning
system will change in accordance with driv-
ing conditions. For this reason, the system
may give a warning even if the tire pressure
does not reach a low enough level, or if the
pressure is higher than the pressure that
was adjusted to when the system was initial-
ized.