OUTLINE
Since tire pressure decreases over time, regular adjustments are necessary. When the tire pressure warning system detects that the pressure of a tire has dropped below the warning threshold, it will illuminate the tire pressure warning light to warn the driver.
A direct-sensing type tire pressure warning system is used. Also, a tire inflation pressure display function is provided.
The 5 tire pressure warning valve and transmitters each send tire inflation pressure, temperature and ID code information to the tire pressure warning ECU and receiver.
The tire pressure warning ECU and receiver, which consists of an antenna, a receiver and an ECU, monitors the tire pressure warning valve and transmitters to detect low tire pressure in each of the 5 tires (including spare tire).
The operation of the tire pressure warning system includes an inflation pressure display function, warning function, initial check function, initialization function and diagnosis function.
The tire inflation pressure display function is a function that displays the pressure of each tire together with the position of the identified tire on the multi-information display.
The transmission cycle with which the information is sent from a tire pressure warning valve and transmitter to the pressure warning ECU and receiver is determined as follows based on the travel mode and the acceleration sensor built into each tire pressure warning valve and transmitter. Since the acceleration sensor is used only to determine if the vehicle is being driven, the value of rotational acceleration is not sent to the tire pressure warning ECU and receiver.
| Travel Mode | Transmission Cycle |
|---|---|
| While stopped*1 | 1 time / 1.5 min |
| While traveling*2 | 4 times / 1 min |
Tech Tips
*1: When G that is applied to the acceleration sensor is less than 8 G.
*2: When G that is applied to the acceleration sensor is 8 G or greater.
According to the vehicle driving conditions in an initialization, both the warning threshold and cancellation threshold may be higher than the recommended threshold. Therefore, when a decreased tire pressure warning is activated, the warning may not stop even though the tire inflation pressure has been adjusted to the recommended pressure. In this case, perform initialization.*
Tech Tips
*: Models compliant with ECE-R64 legal regulations
PRECAUTION
The type of tire pressure warning ECU and receiver used on this model differs according to the specifications of the vehicle. The expressions listed in the table below are used in this section.
| Vehicle Specification | Part Name in Manual | Actual Part Name |
|---|---|---|
| Models Compliant with ECE-R64 Legal Regulations | Tire Pressure Warning ECU and Receiver | Tire Pressure Monitor Receiver Assembly |
| Models Compliant with FMVSS138 Legal Regulations | Door Control and Tire Pressure Monitoring System Receiver Assembly |
The system is disabled in the following conditions (When the condition returns to normal, the system will work properly.):
When all of the tires and wheels that have the tire pressure warning valve and transmitters registered with the tire pressure warning ECU and receiver have not been installed.
When all of the transmitter ID codes are not registered with the tire pressure warning ECU and receiver.
When the tire pressure is extremely high [380 kPa (3.9 kgf/cm2, 55 psi) or more].
When the transmitter battery is depleted. (Battery life: approximately 10 years)
The system may become disabled in the following conditions (When the condition returns to normal, the system will work properly.):
When electric devices or facilities using similar radio wave frequencies are nearby.
When a wireless device or other equipment operating at a similar frequency is in use in the vehicle.
When a window tint that affects the radio wave signals is installed.
When there is a lot of snow or ice on the vehicle, in particular around the wheels or wheel housings.
When non-genuine wheels are used.
When tire chains are used.
When aftermarket tire repair sealant is used.
The tire pressure warning system may not function properly if aftermarket tire repair sealant has been used to repair a flat tire. If this type of sealant has been used, the tire pressure warning valve and transmitter should be replaced with a new one after repairing or replacing the tire.
The tire pressure warning light may illuminate due to natural pressure loss caused by air passing through the tires or by changes in tire pressure caused by temperature fluctuations. When adjusting tire pressure, please be aware of the driving conditions and temperature conditions. The tire pressure warning light is prone to illuminate especially in late autumn and during winter.
People with implantable cardiac pacemakers or implantable cardioverter-defibrillators should not come within 45 cm (1.48 ft.) of the initiators. The initiators emit electrical waves for tire position determination which could interfere with the operation of such devices.