How Do Tire Pressure Sensors Work

A tire-pressure sensor is a tiny programmable electronic device that continuously monitors the air pressure within the tire. It is situated in the pressurized pocket formed by the wheel and tire. Tire pressure sensors serve as a crucial component of modern cars, but few people understand how they operate.

There are a lot of myths about where the tire pressure sensors are and how they interact with the ECU (the Computer) in your car. In addition, many people are unsure what to do if their tire pressure sensor detects low readings or if the sensor fails. Continue reading to learn more about how tire pressure sensors operate.

Here is how the tire pressure sensor work

The tire pressure sensor is typically a battery-powered direct sensor (implying it is directly incorporated with the wheel as well as a tire) that transmits data to the vehicle’s instrument cluster via radiofrequency. The mechanism is set as long as the vehicle’s tires are within a specified pressure range of one another.

If one or even more tires gain or lose more than a specific amount of pressure (approximately 20 percent to about 30 percent of the air pressure difference between the others), the device cluster panel will be triggered, and a warning indicator light or what is commonly referred as a “low tire pressure” light will illuminate.

In certain versions, there might also be an information center that displays each tire’s air pressure. While most of these sensors are incorporated with the valve stem, others are strapped to the rim together with a steel band. A tire sticker that has the manufacturer’s advised tire pressure for the front, as well as rear tires, is normally situated on driver’s side door frame.

Although this is guidance for air inflation, deviating from the prescribed tire pressure would not necessarily activate the mechanism as long as all tires have an identical amount of air in them. Some vehicles with full-size spare tires which have a sensor in the spare tyre that is designed to track and communicate with the other four.

When a low or flat tire is detected, the dashboard indicator light illuminates and remains illuminated until the tire is fixed or replaced. After such an event, some of the tire sensor systems will need to be reset.

Tire-pressure sensors are an essential part of the Tire Pressure Monitoring System (TPMS). Since the 2008 model year, when they became mandatory in the United States, millions of these devices have been installed in passenger cars. Tire-pressure sensors are normally operated by batteries and connected to the valve-stem assembly of every tire.

The Downside and Future

The customer faces some problems with these direct battery-driven sensors because they are large and expire after a certain period. If the tire is not replaced with care, the TPMS sensor can be compromised. The cost of replacing the sensor is very high. The sensors are quite heavier than a normal valve stem, so they can easily throw the vehicle’s balance off.

An indirect TPMS sensor (one that is not integrated with wheel and tire) will do away with the internal sensor by monitoring the tire’s angular velocity with an external sensor. Since it is slightly smaller in diameter, the tire which has a lower air pressure compared to the others will have to rotate at a faster speed than the others, triggering the mechanism. This device would also remove the possibility of tire replacement and damage to a direct sensor.

What are the locations of tire pressure sensors?

Tire pressure sensors, as you would expect, are close to the tires. But where exactly are they to be found? There is a small pocket of space that is available between the wheel and tire when the pressurized tire is attached to it. This is the location of the sensor.

This position allows it to maintain regular contact with the tire, which is critical for getting accurate readings on the condition of your tires. The sensor, on the other hand, is securely attached to the wheel. Also, during spirited driving, this ensures safety and stability.

Frequently Asked Questions

What is the role of the tire pressure monitoring system?

Sensors in the tire or on the vehicle transmit data to one or more modules in the vehicle. These modules are pre-programmed to work in a variety of circumstances. This is usually between 28 – 35 pounds per square inch (psi) of the air in the tire for direct tire pressure control.

Sensors aren’t used in the indirect tire pressure monitoring systems, or even at least not the pressure sensors. The systems use data from wheel speed sensors to figure out how big a tire is based on how much it rotates.

TPMS reset button is usually found under the steering wheel of a car. If you cannot find it, look through your car’s owner’s manual. If the TPMS warning light remains illuminated after you’ve loaded your tires with air, you should double-check the tires to ensure they’re properly inflated.

If the air pressure is low, you might have a leak and need to replace or repair the tire. Although some aftermarket devices are mounted on the outside of the tire, the majority of manufacturers utilize an inside-the-tire sensor.

Final Note

Your tire pressure sensor can, as you are probably aware, illuminate an icon on the dashboard. However, unless the tire pressure is extremely low, the tire pressure sensor cannot illuminate this symbol. The threshold varies from one manufacturer to the other, but it is usually about 25% lower than the average tire pressure reading. This is sufficiently low that you can take it to the nearest mechanic right away to get it checked.

Tire pressure sensors do, unfortunately, fail from time to time. When the tire pressure sensor fails, the warning light should illuminate. This can be perplexing because you can fill your tires just to discover that the light continues to be on.  If this is the situation, the tire pressure sensor isn’t working properly. You can have it repaired as soon as possible so that you can determine whether or not you do have a low tire pressure.

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