Vehicles today tend to be filled with a host of technological systems and features that help owners know and understand more about their automobiles. One of the main purposes of the systems is to let drivers know when there is something wrong with the vehicle. With some systems, it might be a sound alert, or it could be a light on your dashboard. 

Many people panic at the first sign of a light popping up on their display. They worry that it’s going to be a major problem and that it will cost a lot to fix. While it’s easy to understand that anxiety, you will be better served by taking a deep breath and learning what the lights mean. Below, you’ll learn more about one of these lights—the TPMS light.

What Is TPMS?

TPMS stands for the tire pressure monitoring system. This is a system of sensors in your vehicle that is meant to let you know when one or more of your tires is underinflated or overinflated.

If the tire pressure is too low, it could lead to more difficult diving conditions, accelerated wear and tear on your tires, and it could even lead to fire failure. Overinflation is just as much of a problem. When the tire has too much air in it, excess wear and tear will occur. It also means that the tire is stiffer and doesn’t bend like it should, so less of the tire’s surface is contacting the road. It can lead to dangerous driving conditions.

The goal of the sensor system is to help alert drivers when there is a problem, so it can be taken care of as soon as possible. This helps to reduce issues with the tires. Although the TPMS light may not seem as big of a problem as something like bad breaks, it’s also not something you want to ignore.

How Does TPMS Work?

There are two types of TPMS systems in use today—direct and indirect. They work differently and have different pros and cons.

Indirect

An indirect system uses wheel speed sensors that the anti-lock brake system uses. They measure wheel revolutions and use the data they pick up to interpret the size of the vehicle’s tires. If a wheel is spinning faster than it should, the computer would then pick up that the tire is likely underinflated and would provide an alert to the driver.

It’s important to realize that the indirect system doesn’t measure the tire pressure itself. Instead, it extrapolates from other data that it collects and then infers that there is likely a tire pressure problem based on the speed at which the tire is turning.

These systems are often used because they are cheaper than direct TPMS and they require less maintenance and programming. However, if you change tire sizes, they are going to be inaccurate. If there is uneven wear on the tires, they will be inaccurate, too. Additionally, the system needs to be reset after inflation and after tire rotations.

Direct

Direct TPMS systems use pressure monitoring sensors in each of the tires. These monitor the specific pressure levels in each of the tires. The system sends the data to a control module, where it will be analyzed and interpreted. If the pressure is incorrect, the TPMS light will come on to let you know that there is a problem with the tires.

As you can imagine, this is going to be far more accurate than the indirect system. The batteries in the sensors will last for about a decade or more, and resyncing is easy after replacing tires or getting a tire rotation, although you will need the help of a professional. These systems are more expensive, increasing the price of the vehicle when purchasing. They are also more costly when replacing or repairing them.

What Does a TPMS Warning Light Mean?

The TPMS warning light is shaped like an upside-down horseshoe with tire tread on the bottom and an exclamation point in the middle. It is typically a yellow indicator light, and when it comes on, it means that your tires do not have the optimal amount of pressure in them.

When this light comes on, the best thing to do is stop driving and check the pressure of each of your tires using a tire pressure gauge. Compare the pressures with the recommended PSI level from your manufacturer. You should be able to find the PSI information on the vehicle’s door jamb, or in the manual, which you should keep in the vehicle.

Generally, the indicator light will come on when the tire has low pressure. This could simply be because of the temperature of the air causing a temporary change to the tire’s air pressure. However, it could also be due to something far more serious, such as damage to the tire.

You should keep in mind that overinflating your tires can be a problem, too. This could also cause the sensor light to appear. This is also why you should always then check the tires with a tire pressure gauge to see whether they are over or underinflated.

What If the Light Comes On and Stays on While You Are Driving?

If you are driving and you notice that the TPMS light comes on and stays on, then it means that one or more of your tires is at a low-pressure level. You will want to get off the road as soon as possible and have the pressure checked in each of your tires to see where the problem might be. If you have a tire pressure gauge, you can check the pressure yourself.

When you find the tire (or tires) with low pressure, add some more air to them to get the pressure back up to where it belongs. Often, this is all you will need to do to fix the light.

However, if there is a leak in the tire or an issue with the sensor, the light will go off again, generally in a day or two. If this happens, you should be sure to take the vehicle to a mechanic to have it examined.

What If the Light Goes On and Off?

Sometimes, the tire pressure is starting to get near the level that is going to trigger an alert. At that point, changes in the air temperature could cause changes to the pressure in the tires, which means the lights will go on and off as the temperature changes.

You most often see this happening overnight when the temperature drops. The light may turn on and then go off during the daytime because the pressure rises with the temperature. Once again, using a gauge will help. It will let you know whether your air pressure in the tires is near the cusp of being considered low. If it is, just add some more air to get to the manufacturer’s recommended PSI. This should stop the issues with the TPMS light.

What If the Light Flashes and Then Stays On?

Often, when you get in your vehicle and turn it on, all of the lights will turn on and then off. However, if you notice that the TPMS light starts to flash for between 60 and 90 seconds each time you start your car and then stays on, it is an indicator that you need to get the TPMS checked. You will want to take it to a mechanic to have it inspected, as it means it is not functioning properly. Until it is fixed, it will not be able to warn you about having low tire pressure.

Until you get it repaired, you will want to check the pressure in the tires yourself, using the tire pressure gauge we mentioned before. Add air to the tires if needed.

Don’t Overinflate Your Tires

When putting air in your tires, make sure that you use the recommended PSI and not the level that’s listed on the tire sidewall. The number on the sidewall is the maximum inflation level that the tire can hold. If you put in that much air, it could cause the vehicle to have a rough, bumpy ride. There is also a greater risk of the tire blowing out when it is overinflated like that.

Is It Safe to Drive with the TPMS Light On?

This is one of the most common questions people ask when it comes to the TPMS light. They essentially want to know just how important it is to have repaired and how long they can get away without repairing it.

The truth of the matter is that it’s quite important to have this system working properly. Without it, you may have low tire pressure without realizing it, which is going to change the way your car handles, wear your tires down faster, and increase the risk of having a tire blow out. All of these have the potential to be very dangerous. You should make sure to have the repair completed as quickly as possible. 

Is the TPMS a Replacement for Getting Regular Tire Pressure Checks?

One of the other common questions people tend to ask is whether having a TPMS system means that they shouldn’t have their tire pressure checked regularly. While the TPMS system is great to have and it can give you an indication of what’s happening with your tire pressure, it isn’t a replacement. You should still have your tire pressure checked regularly, as there are sometimes limitations to what the TPMS can do.

Just to be on the safe side, you will want to check your tire pressure about once a month with a tire gauge. It’s easy to do and should only take you a few minutes. If you don’t have your own tire pressure gauge, you can find them online for less than $20.

Can You Repair Your Own TPMS?

Although you might be able to get the light to go off by adding the proper amount of air to your tires, you can’t fix a broken sensor on your own. Instead, you will need to take the vehicle to a mechanic to have it done. You will find that most tire shops can handle this type of issue, and it shouldn’t take them long to have it replaced and ready to go for you.

Tips for Keeping Things in Shape

You want your TPMS to work well, and you want to be sure your tires have the proper amount of inflation. There are a few things you can do that will help with this. For starters, keep the information in this article in mind, and start paying attention to the TPMS light. Watch for changes. Does it blink when you start the car? Is it solid? The way it behaves is an indicator of what is wrong and what needs to be done.

Also, never just guess at your tire pressures when adding air. This is a bad habit that many people have. They feel that they should add some air to their tires, or they notice that the light is on, so they “eyeball” how much to put into the tires. However, unless you take the extra minute or two to use a tire pressure gauge, you will find that are likely putting in too much air just to get the TPMS light to go off.

If you have an older vehicle that hasn’t had the TPMS sensors replaced, you might want to have your tire shop check them out. As mentioned earlier, most of the sensors will last for about a decade or so. Although it’s not necessary to change them out early, it may be something to consider. 

Finally, always err on the side of caution. If the TPMS light is going off, don’t ignore it. This will just lead to more problems for you down the road. A little caution and care always go a long way with your vehicles.

Resources:

https://www.thedrive.com/maintenance-repair/36753/tpms-light

https://www.firestonecompleteautocare.com/blog/tires/what-does-tpms-mean/ 

https://www.bridgestonetire.com/learn/maintenance/tpms-light-on/#:~:text=The%20purpose%20of%20the%20TPMS,wear%20and%20possible%20tire%20failure