Nobody likes a pesky light on your dashboard, but what if the light never turns off? With a TPMS warning light, this could happen. If you have a TPMS light that won’t turn off, you came to the right place.
To put it broadly, there’s either an issue with the TPMS sensor, tire, or temperature. A cold tire will report lower psi’s while a hot tire will show high psi’s. If there’s a puncture, you just rotated or changed your tires, or you have a spare tire on, the light will stay on until the problem is fixed. If the sensor itself is broken, then it can’t communicate with your car’s onboard computer, giving you a warning light.
In this beginner’s guide, I’ll walk you through the whole troubleshooting and solution process. The fixes are generally pretty easy, but it’s important that you start fixing your car as soon as you notice the light.
What Is a TPMS Light?
The TPMS light is simply a dashboard notification that’s tied to your tires’ TPMS sensors. It stands for Tire Pressure Monitoring System (TPMS), and a sensor can be found in each of your tires.
The TPMS light on your dashboard looks like a deflated tire with an exclamation mark in the middle. Most cars don’t give you any information beyond that.
How the TPMS Sensor Works
The sensor in your tire works one of two ways. A “direct TPMS” sensor will be tied directly to the wheel. The sensor is constantly checking the psi, and comparing that to the value that the manufacturer recommends.
If a direct TPMS sensor notices a pressure that’s too high or too low, it will trigger the warning light on your dashboard.
An “indirect TPMS” takes a more roundabout way of doing this. Instead, it ties into your car’s anti-lock brake system (ABS) in order to see how quickly each tire is rotating. It then compares the rotation speeds in order to see if the pressures are the same.
If one tire’s psi is too high or low, then it won’t rotate at the same speed as the other three. Then, the dashboard light will illuminate.
Once the sensor realizes that something’s wrong with your tire pressure, that lovely TPMS light will start shining on your dashboard.
Why the TPMS Is So Important
What might seem like an annoying warning is actually very important. In a case where your TPMS sensor goes off, it means that one or more tires have pressure outside of the manufacturer’s suggestion.
If the tire pressure is wrong, then a few things can happen:
- Your car will take longer to stop
- Your car will handle worse
- Your fuel efficiency will go down
- Your overall performance will worsen
- Your tire can explode
As you can see, none of these events are good. That means that you need to take the warning light seriously, find out why it’s on, and remedy the situation. Every extra mile that you drive in your car after this light comes on is potentially dangerous.
If the TPMS light is active due to a puncture, and the hole is in the wrong place, then a blowout can occur. A tire blowout can easily be 10 times more expensive than simply replacing the tire in the first place.
I’m only mentioning this to reinforce how time-critical this repair is. Take a look at the next sections so you can quickly fix your car.
7 Reasons Why Your TPMS Light is On
Let me talk about some potential culprits, here. This section is all about finding out why your TPMS light is on your dashboard.
1. You’re Driving on a Spare
Spare tires are built to be lighter, less expensive backups in case of an emergency. As such, they don’t have fancy rims, sturdy wheels, high-performance tire rubber, or even TPMS sensors.
If you just changed your tire and you’re riding on a spare tire, there’s a good chance the TPMS light will stay on your dashboard. Your car’s computer is looking for a signal from a sensor that doesn’t exist, so it’s constantly going to show a warning light.
2. You Just Changed Your Tires
Another issue is that it can take a while for your car to start talking with a TPMS sensor again. If you just put on a new tire, a set of tires, or replaced all four, then the light can stay on the dashboard for a little bit. Again, this is just during a period where your car connects to the new sensors and translates their signal.
3. Your Air Pressure Is Wrong
In my experience, the leading culprit of a TPMS light that’s on is a tire that has wrong pressure in it. If just one or all four of your tires have pressures that are too low or high, the light will turn on and stay on.
There are a lot of reasons why the pressure could be wrong (most of the reasons will be addressed in the next section). It doesn’t mean you did anything wrong, and the solution is typically inexpensive and easy.
4. There’s a Puncture
If there’s a hole in your tire, then air is going to escape. Since your tire is leaking air and no longer air-tight, then the pressure will drop. This will cause the psi to dip below the manufacturer’s suggested rating, triggering the light on your dashboard.
5. A Change in Temperature
Another reason that your tire pressure might change is due to changing weather. Hot air molecules expand while cold air molecules contract. This phenomenon causes the pressure in your tires to change as the weather goes from cold to hot and vice versa.
6. The Sensor is Faulty
Another problem could simply be a faulty sensor. Remember, the computer in your car relies on the sensor to give the status of your tire. If the sensor is dead or on the fritz, it can either report a wildly wrong pressure or no pressure at all.
In either of these scenarios, the light will be turned on. If the light goes off and on randomly and flickers sometimes, then there’s a good chance it’s a bad sensor.
7. You Just Rotated Your Tires
If you just rotated your tires, your TPMS sensors are in the wrong positions. The front axle typically calls for a different psi than the rear axle. In a lot of cars, this could be a difference of 4 or more psi — a figure that’s pretty significant.
If you took your rear tire and moved it to the front, the pressure will need to change. However, the sensor in the tire still thinks that you’re dealing with a rear tire, despite the fact that it’s physically located in the front of your car now. As a result, it will read a pressure that’s 4 psi too high, for instance, and cause that light on your dashboard to illuminate.
Ways to Turn Off Your TPMS Light
If you have a pesky TPMS light that won’t turn off, take a look at these solutions. These will deal with the 7 reasons I just described in the previous section.
Drive for a While
If you installed a new tire, then it could just be connecting with the computer and gathering data. Tire experts suggest that you drive at or above 50mph for about 10 minutes after changing your tires. This gives your car enough time to get an accurate reading on your tires.
After this time, the light could just go away on its own. If it doesn’t, then there’s something else going on. Since these are new tires, it’s unlikely that they have a puncture or damage to them, but it’s still worth checking. Sometimes the tire just needs air and isn’t flat.
Use the TPMS Reset Button
In modern cars, there’s an option to reset your TPMS after you do a tire rotation, put on a new tire, or have a stubborn light that won’t go away. On a Civic specifically, it’s a matter of navigating through the touchscreen display and forcing a “TPMS Calibration”.
You might also have arrow keys on your steering wheel that lets you navigate a screen on your dashboard. Under a Maintenance screen, you should be able to perform the same task. Other vehicles make it easy by having a specific button you can press, whereas in other cars you have to dig in the menu of the cluster or center info display to reset it.
Doing this tells your car that you just did some maintenance that could have changed the location or status of your TPMS sensors. It acts like a soft reset. The car will then try checking the pressures again and the light will go away if there are no physical damages to the tires or sensors.
Check Your Tire Pressure
I would always suggest starting out by checking your tire pressure. As I mentioned, this is usually the reason why the light is on in the first place.
Remove the twistable plastic caps on your tire’s valve stem. Put in a tire pressure gauge and read what your tire’s psi is. Remember that value and then open your driver’s door. Look in the doorjamb and check for a printed sticker that says what psi you should have in your front and rear tires.
Compare the suggested value to the value you read on the gauge. If the two numbers are really far apart, take another reading with the gauge.
If the measured psi is too low, then you need to fill up your tire. If it’s too high, you’ll need to press a rock or hard tool against the tire’s valve stem to let out more air.
Check for a Puncture
Another way to check the health of your tires is to look for a puncture. As a reminder, any sized hole will allow air to escape your tires and decrease your air pressure.
You should start looking for a puncture with your wheels and tires still on your car (without removing the wheels or jacking up your car). This forces more pressure on the tires, causing the air to come out quicker, allowing you to spot a leak easier.
You can check for a puncture in a number of ways. First, just try listening. With the air escaping, you’ll hear a faint hissing noise with your ear near the tire. Next, look around the tread for a nail, screw, or anything lodged in the rubber.
Finally, you can try to do a spray test before removing the wheel and checking on a table. A spray test entails using a spray bottle filled with water and a little bit of dish soap. Shake the bottle and spray it all over your tires. Check to see if any part of the tire starts bubbling aggressively. This is a sign that air is escaping in this area and causing bubbles to form in the soapy water.
If you can’t find a puncture from any of those methods, then take off the wheel and take a closer look at it. If you have a workshop table you can use, it makes it a little easier. You just want to look all around the tire for any type of puncture. You might want to redo the spray test now that you have more access to the full tire.
Replace Your Spare Tire
If you put on a spare tire and suddenly get a TPMS warning light, then you need to replace the spare tire. In general, you should never rely on a spare tire. It’s just there to get you out of an emergency so you can immediately drive home or right to an auto shop.
The spare tire doesn’t have a TPMS sensor, so it’s not reporting any psi value at all. Your car’s computer sees a 0 value and sends a warning light.
Reprogram the TPMS Sensors
Tire shops and mechanics have a special tool that plugs into your car under the dash. This tool lets the mechanic tell your car that they just rotated the tires, so the TPMS sensors have shuffled around.
By doing this reprogramming, you can force your car’s computer to look for different values in each TPMS sensor. Instead of expecting a high pressure in a tire that was moved to the rear of your car, it will be reset to look for the lower, correct psi value.
Doing this on your own takes a special tool that costs money and is used very infrequently.
Warm Up the Tires
Changing temperatures outside can really impact your car’s tire pressures. To combat this, it’s important that you warm up your tires before trusting the psi value.
On a cold day, it’s not rare for your car to think you have low tire pressure until you drive for a little bit. It’s the same reason why I suggest checking your tire pressure after you drove for 15 to 20 minutes at highway speeds.
The goal is to just drive long enough for your tires to warm up. If you go through your whole commute and your TPMS light goes off, then there’s a good chance your tires were just too cold in the morning.
Moving forward, you can avoid this issue by parking in a garage overnight. If that’s an option for you, you’ll do a lot more than just avoid TPMS lights — you’ll also help your car live longer, protect your paint, and avoid natural damages to your vehicle.
Take it to a Mechanic
If you go through all this troubleshooting and can’t find the culprit, it’s not the end of the world. I would suggest taking your car to a trusted mechanic and asking them to take a look at your tires.
I’ve had experiences in the past where it was an easy solution, and the mechanic quickly fixed the problem for free and gave me back the keys. I can’t promise this will happen for you, but it’s possible.
The good news is that simple problems with a TPMS sensor aren’t hard to deal with. The only potentially expensive issue would be something with your tire or set of tires that forces you to replace your tires. Unless the tires are brand-new, you can’t just replace one. You have to replace a minimum of two, and typically all four tires to keep you safe on the road.
Now that you know why your TPMS light is on and how to fix it, you should take some time to go through the steps I highlighted earlier. Make sure you prioritize this repair, in order to save you a lot of time and money in the future.
If you want to learn more about DIY repairs on your car, then check out my site. I post new content weekly, so keep checking in to see what’s new. Drop a comment below if this guide helped you at all. As always, you can look through my ultimate list of helpful car products to make your car-driving life a little easier.