Toyota C-HR. The tire pressure light blinking

The tire pressure light turns on when the pressure is insufficient. But when the light flashes for 1 minute and then stays on, sadly means that the RF transmitter has a fault and needs to be substituted.

Every tire has a Wi-Fi transmitter. It is called TPMS. It costs about $200.

Normally this is a failure.

Exception:

If you changed the tires and your mechanic forgot to reset the ECU.

A TPMS (Tire Pressure Monitoring System) sensor is a device installed in the wheel of a vehicle to constantly monitor the air pressure inside the tires. It sends real-time tire pressure information to the vehicle's computer system or directly to the driver via a dashboard indicator or a warning light. This system is crucial for maintaining proper tire pressure, which can lead to improved vehicle safety, fuel efficiency, and extended tire life.

There are two main types of TPMS sensors:

Direct TPMS 

These sensors are mounted inside the tire and measure the actual air pressure in each tire. They send this information to the vehicle’s computer system. Direct TPMS provides accurate and real-time tire pressure data. Each sensor is battery-powered, and the batteries typically last 5 to 10 years. When the battery dies, the entire sensor usually needs to be replaced.

Indirect TPMS

 Instead of measuring the tire pressure directly, indirect TPMS systems use the vehicle's antilock braking system (ABS) sensors to monitor the speed of each wheel. The system infers pressure changes from variations in wheel speed; for example, an under-inflated tire will rotate faster than a properly inflated one. Indirect TPMS is less expensive than direct TPMS but may not be as accurate because it doesn't measure the pressure directly.

Transmission

TPMS (Tire Pressure Monitoring System) sensors typically transmit data at radio frequencies (RF) in the 315 MHz or 433 MHz bands. The specific frequency can vary depending on the region and the specific vehicle make and model.

In the United States, the most common frequency used by TPMS sensors is 315 MHz.

In Europe and other parts of the world, 433 MHz is more commonly used.

These frequencies allow the TPMS sensors to communicate wirelessly with the vehicle's onboard computer system or receiver. The transmission of data is not continuous but occurs at regular intervals or when a significant change in tire pressure is detected. Some systems may also transmit data when the vehicle starts or at specific speeds.

The choice of frequency ensures that the TPMS system operates effectively without interfering with other vehicle electronic systems or external devices. It's important for replacement sensors to be compatible with the vehicle's specific TPMS frequency to ensure accurate communication and functionality.

Benefits of TPMS

Safety. Properly inflated tires are less likely to fail at high speeds.

Economy. Tires at the correct pressure level offer better fuel efficiency.

Environment. Optimizing tire pressure helps reduce tire wear, leading to fewer tires being discarded.

Performance. Proper tire pressure ensures better vehicle handling and braking efficiency.

Maintenance and Replacement

For direct TPMS, sensors may need to be replaced when the battery dies or if the sensor is damaged. Sensor reprogramming or recalibration may be required when tires are rotated, replaced, or when purchasing a new sensor.

Indirect TPMS systems generally require less maintenance but may need recalibration following tire rotation, tire replacement, or changes in tire pressure.

It's important to regularly check your vehicle's tire pressure, even if it's equipped with TPMS, to ensure your tires are properly inflated and to maintain safety and efficiency on the road.