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 lower than 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.
The tire pressure monitor receiver assembly receives tire pressure, temperature and ID code information from the 4 or 5* tire pressure monitor valve sub-assemblies.
*: Models with full size spare tire
The tire pressure monitor receiver assembly is equipped with a built-in tire pressure warning ECU. The tire pressure warning ECU monitors the tire pressure monitor valve sub-assemblies to detect low tire pressure in each of the 5 tires (including spare tire).
The operation of the tire pressure warning system includes a tire pressure warning function, initial check function, initialization function and diagnosis function.
The transmission cycle with which the information is sent from the tire pressure monitor valve sub-assemblies to the tire pressure monitor receiver assembly is determined as follows based on the travel mode and the acceleration sensor built into each tire pressure monitor valve sub-assembly. 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 monitor receiver assembly.
| Travel Mode | Transmission Cycle |
|---|---|
| While stopping*1 | 1 time / 1.5 min |
| While traveling*2 | 4 times / 1 min |
Tech Tips
*1: When the g-force that is applied to the acceleration sensor is less than 8 G.
*2: When the g-force that is applied to the acceleration sensor is 8 G or greater.
According to the vehicle driving conditions, 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.*
*: Models compliant with ECE-R64 legal regulations
PRECAUTION
The system is disabled in the following conditions (When the condition becomes normal, the system will work properly.):
When all of the tires and wheels that have the tire pressure monitor valve sub-assemblies, registered with the tire pressure monitor receiver assembly have not been installed.
When all of the transmitter ID codes are not registered with the tire pressure monitor receiver assembly.
When the tire pressure is extremely high [380 kPa (3.9 kgf/cm2, 3.8 bar) 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 becomes 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 an aftermarket tire repair sealant is used.
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.