TOYOTA SIENNA 2007 Service Repair Manual

TW–16TIRE AND WHEEL – TIRE PRESSURE WARNING SYSTEM
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SYSTEM DESCRIPTION
1. DESCRIPTION OF SYSTEM
(a) A tire pressure warning valve and transmitter is
equipped with a tire pressure sensor and a
transmitter and is installed in a tire wheel assembly.
The sensor measures the tire pressure. The
measured value and transmitter ID are transmitted
to the tire pressure warning antenna and receiver on
the body as radio waves and then sent to the tire
pressure warning ECU from the tire pressure
warning antenna and receiver. If the transmitter ID
has already been registered, the ECU compares the
measured air pressure value with the specified
value. When the value is less than the specified
value registered in the tire pressure warning ECU,
the warning light on the combination meter comes
on.
• The tire pressure warning reset switch addresses
the differences in the standard pressure of the
tire.
2. INITIAL CHECK
(a) The tire pressure warning light turns on for 3
seconds after the ignition switch ON and then goes
off.
HINT:
If the warning light does not turn on for 3 seconds,
troubleshoot the tire pressure warning light circuit.
C159181E01
C124985E04
Trouble Area See procedure
Tire pressure warning light circuitTW-74

TIRE AND WHEEL – TIRE PRESSURE WARNING SYSTEMTW–17
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3. WHEN TIRE PRESSURE WARNING LIGHT IS LIT
(a) When the tire pressure warning light does not go off,
or when it comes on during driving, check tire
pressure. If the tire pressure warning light comes on
within several hours after adjusting the tire
pressure, the tire may have a slow air leak.
(b) Under the following conditions, the system may not
function properly.
• Facilities or devices that use similar radio
frequencies are located in the vicinity of the
vehicle.
• A radio device of similar frequency is used in the
vehicle.
• A large amount of snow or ice is stuck to the
vehicle, especially onto the wheels and around
the wheel houses.
• The ID of the tire pressure warning valve and
transmitter has not been registered with the
ECU.
• A film or window tint that may interfere with radio
waves is attached on the glass.
• The battery of the sensor has been depleted.
• The tires without tire pressure warning valve and
transmitter are used.
• Tire chains are used.
• The use of non-genuine wheels may result in the
system failure or air-leak.
• Depending on the tire type, the system may not
function properly even though the specified
wheels are used.
(c) After removing and installing the ECU or a sensor,
check for a diagnostic trouble code and verify that it
is a normal code.
4. FUNCTION OF COMPONENTS
5. TIRE PRESSURE WARNING RESET SWITCH
• By operating the tire pressure warning reset switch,
the tire pressure warning ECU can be set to issue a
warning at an inflation pressure that corresponds to
the standard pressure of tires.
Therefore, the dealer must set the warning threshold
to the proper value in order to comply with the local
regulations.
Components Function
Tire pressure warning valve and transmitterCombined as a single unit with a disc wheel air valve, it measures tire pressure and
temperature and transmits an ID number for measurement value and identification.
Built-in the battery.
Tire pressure warning antenna and receiverReceives and transmits a necessary signal from the transmitter to the tire pressure
warning ECU.
Tire pressure warning ECUReceives a signal from the receiver and identifies it as vehicle's own signal. If the
measured value is equal to or lower than the specified value, it transmits a signal so
that the tire pressure warning light on the combination meter comes on.
Tire pressure warning lightLocated in the combination meter, it informs the driver of lowered tire air pressure
and system failure.
Tire pressure warning reset switch Enters the initialization mode for the change of the standard pressure

TW–18TIRE AND WHEEL – TIRE PRESSURE WARNING SYSTEM
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• Operate the tire pressure warning reset switch only
after the inflation pressures of all tires have been
adjusted on the vehicle.
• To initialize the system, press and hold the tire
pressure warning reset switch for 3 seconds or longer
with the ignition switch ON. After the initialization
process has started, the warning light blinks 3 times
(1 second on, 1 second off).
• During initialization, the tire pressure warning valve
and transmitter measures the inflation pressure of the
tires, and registers the signals that are transmitted
into the tire pressure warning ECU at a frequency of
once per 3 minutes. The initialization process is
completed when signals from all the tires have been
received. It takes several minutes.

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INSPECTION
1. INSPECT TIRES
(a) Check the tires for wear and proper inflation
pressure.
Cold tire inflation pressure
(b) Using a dial indicator, check the runout of the tires.
Tire runout:
1.4 mm (0.055 in.) or less
2. ROTATE TIRES
HINT:
Rotate the tires as shown in the illustration.
3. INSPECT WHEEL BALANCE (for Steel Wheel)
(a) Check and adjust the off-the-car balance.
Imbalance after adjustment:
8.0 g (0.018 lb.) or less.
HINT:
If necessary, check and adjust the on-the-car
balance.
Tire size
Front kPa (kgf*cm2, psi) Rear kPa (kgf*cm2, psi)
P215/65R16 96T
P225/60R17 98T240 (2.4, 35) 240 (2.4, 35)
C137874
C140312E01
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4. INSPECT WHEEL BALANCE (for Non-steel Wheel)
(a) Check and adjust the off-the-car balance.
Imbalance after adjustment:
8.0 g (0.018 lb.) or less.
NOTICE:
• Use a cleaning detergent to remove dirt, oil
and water from the surface where the balance
weight is to be adhered.
• Do not touch the sticking surface of the tape.
• Adhere the sticking type balance weight to
the flat position shown in the illustration.
• Push the balance weight securely with a
finger to adhere it to the position.
• Do not reuse the balance weight.
HINT:
• The inner side balance weight should be installed
by clipping it to the rim.
• If necessary, check and adjust the on-the-car
balance.
5. INSPECT FRONT AXLE HUB BEARING LOOSENESS
HINT:
See page AH-5.
6. INSPECT REAR AXLE HUB BEARING LOOSENESS
(for 2WD)
HINT:
See page AH-16.
7. INSPECT REAR AXLE HUB BEARING LOOSENESS
(for 4WD)
HINT:
See page AH-19.
8. INSPECT FRONT AXLE HUB RUNOUT
HINT:
See page AH-5.
9. INSPECT REAR AXLE HUB RUNOUT (for 2WD)
HINT:
See page AH-16.
10. INSPECT REAR AXLE HUB RUNOUT (for 4WD)
HINT:
See page AH-19.
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TIRE AND WHEEL – TIRE AND WHEEL SYSTEMTW–5
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REPAIR
1. INTRODUCTION
(a) This section introduces ways to determine whether
the run-flat tire is repairable or not. Repair must be
performed by following the appropriate procedures.
If a flat tire occurs, it is possible to drive a maximum
of 160 km (100 miles) at a speed below 90 km/h (55
mph) due to the reinforced sidewalls. However, if
the customer continues to drive with low tire
pressure (less than about 100 kPa (1.0 kgf/cm
2,
14.5 psi) and tire pressure warning light is on), the
inside of the sidewall will gradually deteriorate and
the run-flat performance may be reduced.
Therefore, the tires may require replacement.
However, there are some cases where it is possible
to repair a run-flat tire using the same repair method
as for normal tires. Use the following flowchart to
determine if a run-flat tire is repairable.
NOTICE:
When performing repairs, follow the Rubber
Manufacturers Association (RMA) repair
procedures.
2. REPAIR PROCEDURE (CUSTOMER INTERVIEW)
(a) The tire pressure warning system can help
determine the history of the tire's use. The driving
conditions the tire was subjected to while the tire
pressure warning light was on should be obtained
from the customer. Also, make sure to ask the
following questions.
(1) Was the vehicle driven at a speed over 90 km/h
(55 mph) with the tire pressure warning light
on?
(2) Was the vehicle driven over 160 km (100 miles)
with the tire pressure warning light on?
A "Yes" response to either of the above will
greatly reduce the chance of tire repairability.
3. TECHNICIAN TIRE INSPECTION
(a) After the customer interview, it is necessary to
conduct a thorough inspection of the tire after it has
been removed from the wheel. As it is difficult to
identify a tire with low pressure visually, check the
pressure of each tire to determine the tire(s) causing
the low-pressure warning. If the tire is found to be
repairable, follow the RMA repair procedures.
NOTICE:
The deflated tire may be extremely hot, which
may cause injury, so allow the tire to cool prior
to handling.

TW–6TIRE AND WHEEL – TIRE AND WHEEL SYSTEM
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4. TIRE PRESSURE INSPECTION
(a) Inspection procedure
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5. EXTERNAL TIRE INSPECTION
(a) Inspection procedure
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6. INTERNAL TIRE INSPECTION
(a) Inspection procedure
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TIRE AND WHEEL – TIRE AND WHEEL SYSTEMTW–9
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7. RUN-FLAT TIRE REPAIR LIMIT CHART
(a) Tires that have a penetration in the tread area but
meet the above inspection criteria may be repaired
if the guidelines listed below are also met.
Puncture condition (Tread area only)
C113008E01
Diameter (Maximum) Number (Maximum)Distance between holes
(Minimum)
6.4 mm (0.25 in.) 2 406 mm (16 in.)