Tire pressure light on? Here’s what to do.

If your tire pressure light just came on, don’t panic. Of all the warning lights on your dashboard, the tire pressure light is one of the least severe. 

HOWEVER… This doesn’t mean you get to completely ignore it and keep driving like nothing’s wrong with your car. It is a warning light, and something is wrong with your car.

In this article, you’ll learn what  you need to do in order to fix the problem and turn off your tire pressure light.

Why is my tire pressure light on?

The answer to this question is simple: Your tire pressure light turns on because the pressure in one (or more) of your tires is too low. Many tire pressure monitoring systems (TPMS) are triggered when a tire’s air pressure reaches 25% below the ideal pressure for your car’s tires.

Low tire pressure isn’t something you should take lightly. It can be a safety issue, it can damage your tires, and it can impact your car’s gas mileage.

Can I drive with the tire pressure light on?

Generally, you can continue to drive with the tire pressure light on. 

But if the reason your light came on is because you have a flat tire, it’s a different story. 

If your tire pressure light comes on and you feel your car driving differently or if one of the tires is making odd noises, get to a safe spot ASAP and examine your tires for signs of a flat tire.

I hope I don’t have to say this, but I’ll say it anyway – Don’t drive long distances on a flat tire! It’s OK to drive slowly to get to a safe spot, but don’t drive at high speeds or for long distances!

What if I don’t have a flat tire but there’s something stuck in my tire?

If you discover one of your tires has a nail, screw, or some other sharp object stuck in it, you’ll have to make a judgement call as to whether or not you can get your car safely to a tire shop or back home to repair it yourself. 

Oftentimes, an object stuck in a tire doesn’t cause a rapid leak. In fact, It could take weeks (or even longer!) before a noticeable decrease in air pressure happens. But this doesn’t mean you should drive on the damaged tire for a long time. The object should be removed and the tire should be repaired as soon as possible.

If you’re not sure as to whether or not you should keep driving on the damaged tire, it’s a good idea to err on the side of caution and put on your spare tire. Because having a blowout or losing all the air in a tire and continuing to drive can cause unfixable damage to your tire. You may even have to replace the tire, which can cost hundreds. 

A blowout or driving on a flat could also damage your rim… and if this happens you’re getting closer to repair costs in the thousands!

What if my tires look OK?

If there’s no indication of a puncture or a leak in your tire, you don’t necessarily have to take immediate action. So don’t be late for work or miss your sister’s wedding rehearsal dinner because your tire pressure light comes on.

However, you shouldn’t completely ignore your tire pressure light. 

It would be a good idea to check the tire pressure in each of your tires as soon as possible. I recommend carrying a tire pressure gauge in your car. They’re not too expensive, and nor do they take up a lot of space. I personally have a pen style gauge in my car’s glove box.

So when you get to your next destination, quickly check the pressure in each tire. If any of your tires are drastically low, make it a priority to get to a gas station (or someplace with an air compressor) to fill your tires.

How much air should I put in my tires?

Refer to either your car’s owner’s manual or the sticker in your car’s door jamb. These pressure levels are the rates recommended by the manufacturer of your car. These are the safest pressure levels and will allow your car to perform best.

How did I lose pressure in my tires?

Your tires will naturally lose air over time through the process of osmosis. 

Yes, I said osmosis… the movement of molecules through a selectively permeable membrane. It’s one of those high school biology terms you thought you’d never come across again!

All you need to know about osmosis in tires is that air is constantly (and naturally) escaping through the rubber of your tires. You generally lose about 1-3 psi of air in your tires per month.

Other factors that can contribute to air loss are rim damage, rim corrosion, and bad valve stems.

Will a change in temperature turn on my tire pressure light?

 Yes, changes in temperature affect the pressure in your tires and therefore can turn on your tire pressure light.

In cold weather, the air contracts and you lose air pressure. Conversely, in warm weather, the air in your tires will expand. Given this fact, a temperature change can trigger your tire pressure light to turn on.

Generally a 10 degree drop will cause a tire to lose 1 psi of pressure. 

That’s not a lot of pressure change for a big temperature change. Think about it for a minute. To lose 2 psi of pressure due to a temperature change, the air outside would have to go from 40 degrees to 20 degrees in one day. That’s a big temperature jump! Temperature variation like that doesn’t happen often.

So if your tire pressure light is coming on in cold mornings, but goes off later in the day, your tires are still likely under-inflated. There is a tolerance built in to your TPMS that takes temperature changes into consideration. And if your tire pressure light is regularly going on and off, it probably means your tires are close to the edge of that tolerance, So you should inflate your tires to proper levels ASAP.

How to turn off a tire pressure light

Now that you know why your light comes on and what to do when it comes on, how do you turn the darn thing off?

For many cars, the tire pressure light will turn off automatically after you fill the tires to proper levels. In some cars, it will turn off right away. And in others it may take a day or so of driving.

Why is my tire pressure light still on after filling the tires?

If your tire pressure light does not turn off after filling your tires to proper levels, you may need to manually reset your car’s TPMS. This varies from car-to-car. Check your car owner’s manual for instructions on how to reset your car’s TPMS.

My tire pressure light won’t go off

If after filling your tires to proper levels, driving for a few days, and/or resetting your car’s TPMS the tire pressure light STILL won’t go off, don’t panic. There’s a couple more reasons why this could be happening.

Check the pressure in your spare tire

Many TPMS systems also monitor the air level in your car’s spare tire.

This feature causes many drivers agida when it comes to their tire pressure light because not many people think to check the air pressure in their spare tire. Out-of-sight, out-of-mind!

Remember what you learned earlier…. tires naturally lose air pressure due to osmosis over time. And your spare tire is no exception…. It, too, is slowly losing air every single day.  I have first-hand experience with the joy of discovering a flat spare tire when I needed it most. Believe me, it’s no fun!

If the air pressure in your spare tire is low, fill it up to the recommended level and follow the same procedure we discussed earlier… wait a few days, reset your system, etc.

If the pressure in your spare tire is fine, then…

Check your tire pressure on all four tires. Again.

There’s a chance that there may be a slow leak or puncture that you didn’t detect before. Maybe there’s a tiny nail in your tire that is hard to see. Or maybe there’s some dry rot on your valve stem that you didn’t notice. It could be anything!

If you find that one (or more) of your tires has lost a significant amount of air since your (very) recent top-off of air pressure, it would be a good idea to take your car to your local tire shop to have it looked at. They should be able to find where the problem is and get you back on the road. 

What if I see the tire pressure light flashing?

If you notice your tire pressure light flashing, there may be a fault with your car’s TPMS that requires attention. The most common reasons why you have a flashing tire pressure light are…

Power source failure

Some TPMS systems have their own battery. As with any power source, over time it will weaken and need to be replaced. 

TPMS sensor damage

Some TPMS systems have their sensors mounted on the valve stems inside of your tires. So these sensors take on a ton of abuse. Think about it… constant rotation, bumps, and potholes… just to name a few.

Sure, these sensors are made to take on all this abuse, but they can and will wear out and fail over time.

In either case, you’ll likely want to visit your dealer, mechanic, or local tire shop if your tire pressure light starts flashing. 

Can I still drive if my tire pressure light is flashing?

Generally, yes. However, the flashing tire pressure light is a sign of your TPMS not working. As you’ve just learned, this system is a key safety component in your car. So don’t wait too long to get it fixed. 

Conclusion

The tire pressure light is your car’s way of letting you know your tires need some attention. You shouldn’t ignore it. Keeping your tires properly inflated contributes to safety, optimal gas mileage, and longer tire life. So listen to what your car is telling you and give your tires the attention they need.