Tires - Inflation Pressure Adjustment/Compensation
L-SB-0154-08
Rev2
October 29, 2008
Tire Inflation Pressure Compensation and Adjustment
Service Category
Suspension
Section
Tire/Wheel
Market
USA
2010 Lexus Truck RX 350 AWD V6-3.5L (2GR-FE) Page 473
Applicability
TSIB REVISION NOTICE
July 29, 2010 Rev2:
^ Applicability has been updated to include 2011 model year vehicles.
May 14, 2009 Rev1:
^ Applicability has been updated to include 2010 model year vehicles.
^ Figure 1 has been updated, and Celsius temperatures have been removed from the bulletin. Any previous printed versions of this service bulletin
should be discarded.
Introduction
The purpose of this bulletin is to provide a procedure to adjust tire pressure correctly when outside temperature is significantly colder or warmer
than shop temperature.
Seasonal temperature change can dramatically alter tire pressure, which can cause the tire pressure warning lamp to illuminate.
NOTE
This bulletin applies to some 2002 - 2007 model year Lexus vehicles with direct TPWS and all 2008 and newer model year Lexus vehicles.
Warranty Information
Tire Pressure vs. Tire Temperature
Tire temperature is dependent on "cold" tire pressure, driving distance and speed, ambient temperature and road surface temperature. As the
temperature of the tire changes, air in the tire expands and contracts, changing the tire's air pressure. The cold tire pressure for all Lexus models will
vary and will need to be adjusted accordingly.
"Cold" tire pressure, as shown on the tire pressure label on our vehicles, is generally considered to be the pressure in a tire that has not been driven
in the past 4 hours and has been parked outdoors.
The TPWS MUST be initialized with the tire pressure marked on the vehicle placard. Tires are then adjusted according to the information in this
bulletin to ensure that the TPWS light does not illuminate unnecessarily.
2010 Lexus Truck RX 350 AWD V6-3.5L (2GR-FE) Page 474
Tire Pressure Adjustment
Recommended Tire Pressure Adjustment:
NOTE
Use a high quality accurate tire pressure gauge, and check its accuracy regularly.
^ Consider the difference of the air temperature in the workshop and the lowest ambient temperature that may be expected in the next few
weeks (especially in winter).
^ Use the chart (Figure 1) to compensate for temperature of the tires when adjusting tire pressure. Use temperature compensation Example 1
for the spare tire.
Example 1: Temperature Compensation - "Cold" Tires
^ The vehicle has been parked overnight outside shop (vehicle has "cold" tires) and tire pressures are set to 31.9 psi.
^ Workshop temperature is 68锟斤拷 F and expected lowest ambient temperature in the local area is to be 14锟斤拷 F.
^ Subtract the expected lowest temperature (14锟斤拷 F) from the highest expected temperature (68锟斤拷 F) = 54锟斤拷 F.
^ Using the tire pressure chart (Figure 1) find the intersection of the cold tire line at the point corresponding to 54锟斤拷 F and read off the value on
the tire pressure change axis. In this case it would be about 4.9 psi.
^ The tires should be filled to:
31.9 + 4.9 psi = 36.8 psi
Example 2: Temperature Compensation - "Warm" Tires
^ The vehicle has been driven to the shop on surface streets for about 30 minutes (vehicle has "warm" tires) and tire pressures are set to 31.9
psi.
^ Workshop temperature is 68锟斤拷 F and expected lowest ambient temperature in your area is to be 14锟斤拷 F.
^ Subtract the expected lowest temperature (14锟斤拷 F) from the highest expected temperature (68锟斤拷 F) = 54锟斤拷 F.
2010 Lexus Truck RX 350 AWD V6-3.5L (2GR-FE) Page 475
^ Using the Tire Pressure Chart (Figure 1), find the intersection of the warm tire line at the point corresponding to 54锟斤拷 F and read off the value
on the tire pressure change axis. In this case it would be about 6.7 psi.
^ The tires should be filled to:
31.9 + 6.7 psi = 38.6 psi
Example 3: Temperature Compensation - "Hot" Tires
^ The vehicle has been driven to the shop on the highway for at least 60 minutes (vehicle has "hot" tires) and tire pressures are set to 31.9 psi.
^ Workshop temperature is 68锟斤拷 F, and the expected lowest ambient temperature in the area is expected to be 14锟斤拷 F.
^ Subtract the expected lowest temperature (14锟斤拷 F) from the highest expected temperature (68锟斤拷 F) = 54锟斤拷 F.
^ Using the tire pressure chart (Figure 1), find the intersection of the hot tire line at the point corresponding to 54锟斤拷 F, and read off the value on
the tire pressure change axis. In this case it would be about 9.0 psi.
^ The tires should be filled to:
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