Tire Pressure Sensors - A Complete Guide

What is a Tire Pressure Sensor?

A tire pressure sensor is a small component found in a tire pressure monitoring system. This specific component measures the pressure inside the tire and sends back a signal to your vehicle’s monitoring system. The signal is sent through low-frequency radio waves to accurately communicate the information.

The majority of tire pressure sensors are attached to the end of the valve stem on the front of the tire. They usually are battery-powered too. This is why it is so important to fill up your tire with air and properly screw the valve stem cover back onto the tire. Without that cover, you will effectively lose your tire pressure sensor too.

In 2008 in the United States it became a mandatory requirement for all vehicles to use a Tire Pressure Monitoring System. If you drive an older vehicle, it is unlikely you have this function but all new cars should have a reliable TPMS with tire pressure sensors.

How Does a Tire Pressure Sensor Work?

The sensors are programmed to send an alert when the tire pressure has fallen below 25% of the recommended tire PSI. This indicates you are at risk and operating at a low-pressure level.

The process for how this transmission occurs is simple. There are low-frequency radio waves that flow back to your vehicle’s onboard computer to display the current PSI level in the tire. Most vehicles will reveal exactly which tire needs air and may even show the pressure level to you.

After this reading occurs and the signal is transmitted back to your vehicle computer, an amber light will flash on in your vehicle indicating you have low tire pressure. This is your signal to fill up your tires with air. Once they reach the desired air pressure levels again, the light will turn off.

Other vehicles may use a different system, but the process is similar. They rely on indirect sensors that don’t measure the actual pressure of the tire. Instead, tire rotation is measured, and based on how the tire rolls, the system can determine whether the tire is inflated correctly to the most accurate PSI.  

Why Do I Need a Tire Pressure Sensor?

The choice may not be yours in some cases, as your vehicle already may have one installed. However, we recommend everybody to uses a tire pressure sensor because it is one of the most effective tools available to help drivers recognize when their tire pressure is low to improve safety and driving performance.

You will be notified almost instantly when your tire pressure levels drop too low. This means you can go straight to a local gas station or repair shop and have your tires filled with air to get back on the road and drive safely.

Of course, you will need to treat your vehicle with care to maintain the tire pressure sensors last longer. But when that initial tire pressure light comes on, you can quickly react and handle the situation with ease.

What Should I Do if My Tire Pressure Light Comes On?

If you are on the road and your tire pressure warning light comes out, the best solution is to find the closest repair shop or gas station with available air to fill your tires. You can use a manual tire pressure gauge to check each individual tire to determine which ones have low PSI levels.

Some vehicles may have a tire pressure sensor that indicates directly to them which tire is the one that needs to be serviced. However, a simple tool can do the job if your vehicle does not have this feature.

After checking the pressure, fill up all tires to their desired PSI levels. We will cover exactly how to put air in your tires while adhering to PSI levels later in this guide.  

The best thing to do after adding air into your tires is to get back on the road. It might take a few miles of driving for your warning light to go off, depending on your vehicle. If the light doesn’t turn off, it might need to be reset or repaired.

What Causes a Tire Pressure Sensor to Fail?

Like anything else, tire pressure sensors have a specific shelf-life to operate within, and towards the end of that time, they can start to act up and fail. Most tire pressure sensors use batteries, and they last for up to 5-7 years before they need to be replaced. Factors like miles driven and amount of use will play a significant role in how long they last too.

Another reason a tire pressure sensor can fail is internal corrosion within the tire or the valve stem itself. If there is too much pressure being put on the sensor, it will wear down quickly, and the valve stems could crack or break right off from the tire. This would result in a flat tire almost instantly.

A majority of tire pressure sensors use aluminum stems instead of rubber. Because it is aluminum, there are also risks of wiring faults and keyless entry mistakes that can throw off the system and cause it to go offline without a driver realizing it has even happened.

We recommend looking into replace your tire pressure sensors and entire TPMS system after 5-7 years of usage or roughly 70,000 miles. This gives you plenty of time to get the most out of your system while eliminating the risk of it going bad while you are still on the road.

Replacement sensors can be different than the originals. If you are replacing yours, you do not need to use the same exact brand or type again to get the same benefits. They are a compatible component and designed for easy installation.

The best thing you can do is pay attention to any warning lights that appear on your vehicle. They are a good indication of what is going on with your vehicle, and if anything goes wrong with your sensors, you will see your vehicle identify the issue for you.        

How to Change My Tire Pressure Sensor Batteries?

Once your tire pressure sensor batteries die, this means your entire system is down, and you are driving without protection. Unfortunately, the whole system does not operate like a smoke detector where it can be simply taken out to swap the batteries.

This is a much more complex system. When the time comes to replace the batteries, the entire system must be replaced. It is an expensive component to replace in your vehicle but absolutely necessary to maximize your safety on the road.

When a battery is removed from the sensor, it causes the material to melt, and the lithium battery leaks. The best solution is to take it in for a professional to look at. They can test the battery power on your sensors with a specific tool that indicates where the current battery life stands.

Replacement sensors can last between seven to 12 years when newly installed onto your tires. The chances are you will never have to repurchase another sensor after your first replacement.

Sensors do operate individually. If one sensor failed, then you are not required to replace each sensor in every tire. However, it may indicate that if one died, the rest could be soon to follow, so it is best to have them all at least checked for battery life to see what the best decision might be.  

How to Reset My Tire Pressure Sensor

So your light came on. You followed all of the instructions and quickly drove to a gas station to fill your tires with air. You finished and then continued driving. However, the light hasn’t gone off, and now you can’t help but panic. Don’t worry. We have a solution for you.

When this happens, the best solution is the entirely reset the tire pressure light. If you are uncomfortable performing this task, you can also always bring your vehicle to a local repair shop to take a look. But the process is quite simple.

First, you should drive for about 10 minutes on the highway going near 50 MPH. This is recommended to try to see if this helps reset the light. However, if you have been driving already and nothing has happened, we can move on.

1. Park Your Vehicle

You will need to pull over into a safe area to do this. Ideally, look for a parking lot without much traffic.

2. Turn Off Your Vehicle

You can turn off your car now. However, leave your key in the ignition for the next step.

3. Turn the Key to On

You must do this without turning the vehicle on. Simply move the key so the car has enough power to display lights, turn the radio on, and other similar features.

4. Press the TPMS Reset Button

You can look right below your steering wheel to find this button. If you can’t find it, the vehicle manual will mention the exact spot it can be located. After you press the button, hold it down until it blinks three times, and then release it.

5.   Restart Your Car

Allow your car to run for about 20 minutes. This will give it time to reset the sensor. If your light is still on after it resets, you should recheck the tire PSI levels to make sure they are at the correct levels.

How Does Temperature Impact a Tire Pressure Sensor?

The temperature has a very significant impact on how a tire pressure sensor works. In fact, the pressure of a tire will decrease by 1 PSI for every 10 degrees the temperature drops. Cold weather causes the air inside a tire to condense and take up less internal space in the tire.

It is a common occurrence to see your TPMS light come on much more often in the winter. Do not be alarmed. On extremely cold days, you can see your tire lose a significant amount of PSI just from cold temperatures. It does not necessarily mean your tire is going flat.

The best way to handle this situation is by checking your tire pressure to see the exact level. Unless the number is significantly below your recommended levels, it can almost always be attributed to the elements.

However, if your vehicle is carrying a large load, it is best to inflate your tires to the proper levels. You run a higher risk for a flat tire when the maximum load capacity is being tested on a vehicle.

Types of Tire Pressure Monitoring Systems

Two different types of Tire Pressure Monitoring Systems are used in vehicles today. Both options are highly efficient and reliable, but the way they use tire pressure sensors to gauge the inflation levels of a tire is much different.

Direct

The direct TPMS uses a sensor in each tire to accurately measure the tire pressure level. When the pressure drops below 25% of the recommended level, radio frequency waves transmit this information to the vehicle computer.

The vehicle computer then tells the driver about this information through an amber light on your dashboard. This is definitely the more standard way to use tire pressure sensors on vehicles, but both systems are top-rated.

Indirect

The indirect TPMS is a bit different in the approach, but the result is the same. It works with your Antilock Braking System speed sensors instead of a traditional sensor mounted in the wheel. It uses these sensors to analyze the way the tire rolls on the ground when driving.

A tire that is fully inflated to the right PSI level will roll differently on the ground than a tire below the recommended PSI. When the difference is significant enough, the tire sensor will detect the discrepancy and alert the computer system. A tire tressure warning light then comes on to alert the driver.

What’s Better?

While both systems are accurate and provide the information needed, a direct system is much more common and realistic when analyzing tire pressure. The direct system will analyze each tire as its own and better spot low PSI levels this way.

For example, if all four tires were low in PSI with an indirect system you would not be alerted. All of the tires would be rolling the system and the system would assume the tire pressure levels are accurate.    

Tire Pressure Sensor Benefits

How to Put Air in Your Tire

After your tire pressure light comes on, you need to put air in your tire. The process is quite simple to learn and extremely straightforward. It’s worth noting that we recommend always carry a tire pressure gauge in your tire for these situations.

1. Remove the Valve Stem Cap

Start by parking, pulling up to the pump, and remove the valve stem cap from your tire.

2. Check Tire Pressure With Tire Gauge

Use your tire pressure gauge to see what your current PSI levels are. You can look on your vehicle tags to see the recommended PSI level as a target for inflation.

3. Connect Air Hose From the Pump

Take the pump from the air compressor and connect it to your tire. You will hear an air hissing sound until it is correctly attached. After that, the sound fades more as it focuses on filling the tire with air.

4. Allow the Tire to Inflate

After the tire has inflated a bit, you can disconnect the air hose from the tire valve.

5. Check PSI Levels Until Accurate

To be sure you filled up the tire enough, use the tire pressure gauge again to check the PSI level. If you are still too low, reattach the air hose and allow more air in. Repeat this process until you get the desired PSI.

6. Put the Valve Stem Cap Back on the Tire

Seal your tire with the valve stem cap. Remember this step and how important this component is to your entire tire pressure sensor system.

7. Drive Away Safely

The best thing to do after inflating your tires is to drive around. This allows your tires to adjust accordingly.