Toyota Tundra Service Manual: Precaution

PRECAUTION

TIRE PRESSURE WARNING ECU AND RECEIVER EXPRESSIONS

(a) The door control and tire pressure monitoring system receiver assembly is referred to as the tire pressure warning ECU and receiver in this section.

TIRE PRESSURE WARNING SYSTEM PRECAUTION

(a) Tire pressure decreases naturally over time, which also occurs in vehicle models without a tire pressure warning system.

HINT:

Tire pressure decreases by approximately 5 kPa (0.05 kgf/cm2, 0.7 psi) to 10 kPa (0.1 kgf/cm2, 1.5 psi) per month.

(b) It is necessary for the tire pressures to be adjusted periodically because tire pressure decreases naturally over time.

(c) In winter, tire pressure may decrease due to low ambient temperatures (tire pressure decreases by approximately 10 kPa (0.1 kgf/cm2, 1.5 psi) for every 10°C (18°F) drop in the ambient temperature). Therefore, the tire pressure warning system is more likely to indicate a warning if the tire pressures are not adjusted appropriately. If the daily temperature variation is large, increase the pressure of the tires so that the tire pressures are suitable under cold conditions. As a result, unnecessary tire pressure warning operations should decrease.

(d) Depending on the tire type, the system may not function properly even if the specified wheels are used.

(e) To prevent damage to the tire pressure warning valve and transmitter, make sure that the tire pressure warning valve and transmitter does not interfere with the tire bead when installing or removing a tire.

(f) To prevent damage to the tire pressure warning valve and transmitter, before disengaging the tire bead or removing the tire from the wheel, drop the tire pressure warning valve and transmitter into the wheel.

(g) Always use a new grommet, washer and nut when installing a tire pressure warning valve and transmitter to ensure the sealing performance.

(h) When one or more of the tire pressure warning valve and transmitters or the tire pressure warning ECU and receiver is replaced, the transmitter IDs for all of the tire pressure warning valve and transmitters must be re-registered. Before registering the transmitter ID of the new tire pressure warning valve and transmitter, check the Data List and record all of the transmitter IDs that are already registered.

(i) Use only a specified cap. If an unspecified cap is used, it may seize to the tire pressure warning valve and transmitter.

(j) The system is disabled under the following conditions (when the condition returns to normal, the system will work properly).

(1) When all of the tire and wheel assemblies that have the tire pressure warning valve and transmitters registered with the tire pressure warning ECU and receiver have not been installed.

(2) When all of the transmitter ID codes are not registered with the tire pressure warning ECU and receiver.

(3) When a tire pressure is abnormally high (absolute pressure: 480 kPa (4.9 kgf/cm2, 70 psi) or more; relative pressure: 380 kPa (3.9 kgf/cm2, 55 psi) or more).

(4) When a tire pressure warning valve and transmitter battery is depleted.

(k) The system may be disabled under the following conditions (when the condition returns to normal, the system will work properly).

(1) When electric devices or facilities using similar radio frequencies are nearby.

(2) When a wireless device or other equipment operating at a similar frequency is in use in the vehicle.

(3) When a window tint that affects radio wave signals is installed.

(4) When there is a lot of snow or ice on the vehicle, in particular, around the wheels or wheel housing.

(5) When non-genuine wheels are used.

(6) When tire chains are used.

(7) When aftermarket tire repair sealant is used.

CAUTION:

After use of tire repair sealant, replacement of the tire pressure warning valve and transmitter is required to ensure normal system operation. (Normal system operation cannot be ensured by only repairing or replacing the tire.)

(l) Tire Inflation Pressure Display Function:

(1) The tire inflation pressure display function displays the position and pressure of each tire on the multi-information display. If the position and pressure of each tire is not displayed, the problem may be alleviated by driving the vehicle to a location where the signal reception is better.

NECESSARY PROCEDURES WHEN REPLACING PARTS

(a) ID Registration

When replacing the tire pressure warning valve and transmitter and tire pressure warning ECU and receiver, perform ID registration for the tire pressure warning valve and transmitter.

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(b) Initialization

After performing ID registration for the tire pressure warning valve and transmitter, make sure to initialize the tire pressure warning system.

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(c) Tire Inflation Pressure Display Function:

Tire Position Identification

After performing ID registration for the tire pressure warning valve and transmitter and initializing the tire pressure warning system, perform tire position identification.

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