You’re driving along and suddenly a little horseshoe-shaped icon (sometimes with an exclamation point) lights up on your dashboard. It’s easy to ignore—especially if the car feels totally normal—but that TPMS light is your vehicle’s way of saying, “Hey, your tires need attention.”

TPMS stands for Tire Pressure Monitoring System. In plain terms, it’s designed to alert you when one or more tires are underinflated (and in some vehicles, when there’s a system fault). Since tires affect braking, handling, fuel economy, and overall safety, that small light can be a big deal.

This guide breaks down what the TPMS light means, the most common causes, how to reset it safely, and the situations where you should stop driving and get help. We’ll also talk about the difference between a slow leak and a sensor issue, and how seasonal temperature swings can make the light pop on at the most inconvenient times.

TPMS basics: what the system is actually watching

TPMS is one of those features that quietly does its job in the background—until it doesn’t. The system exists because underinflated tires are extremely common and can lead to longer stopping distances, reduced stability, and premature tire wear. Even a few PSI low can change how your car behaves.

There are two main types of TPMS: direct and indirect. Direct TPMS uses pressure sensors inside each wheel (usually attached to the valve stem) to measure tire pressure and send that data to the vehicle. Indirect TPMS doesn’t measure pressure directly; instead, it uses wheel speed sensors (the same ones used for ABS) to infer when a tire is low based on changes in rotation speed.

Most modern vehicles use direct TPMS. That’s good because it’s more accurate, but it also means you have batteries and sensors that can fail over time. Indirect systems are simpler, but they can be thrown off by tire rotations, uneven tire wear, or changes in tire size.

What your TPMS light is trying to tell you

Not all TPMS warnings are identical. Some vehicles show a steady light when pressure is low and a flashing light when there’s a system malfunction. Others will display the PSI for each tire in the info screen. The key is to pay attention to whether the light is steady, flashing, or accompanied by a message.

A steady TPMS light usually means at least one tire is below the recommended pressure. That doesn’t necessarily mean it’s dangerously low, but it does mean you should check it soon—ideally the same day. A flashing TPMS light (often flashing for a minute and then staying solid) usually points to a TPMS sensor or communication problem.

If your vehicle shows individual tire pressures, use that info as a starting point, but still verify with a quality gauge. Dashboard readings can lag behind real conditions, especially right after you fill a tire or if the car hasn’t been driven long enough for the system to update.

The most common reasons the TPMS light comes on

Normal temperature swings (the “first cold morning” surprise)

If your TPMS light tends to appear when the weather changes, you’re not imagining it. Tire pressure drops as temperatures fall—roughly 1 PSI for every 10°F (about 6°C) decrease in ambient temperature. That means a tire that was fine last week can become “low” overnight.

This is especially common in fall and early winter. You might see the light in the morning, then it disappears after you drive and the tires warm up. Even if it turns off, it’s still worth checking pressures when the tires are cold (before driving) and topping up to the door-jamb specification.

One helpful habit: check tire pressure monthly and whenever the season changes. It’s quick, it saves tire wear, and it reduces the odds of getting stranded with a flat that started as a slow leak.

Slow leaks from nails, screws, or tiny punctures

The classic TPMS scenario is a slow leak. A screw or nail can lodge in the tread and let air seep out gradually over days or weeks. The tire may look fine, but the pressure keeps dropping until the sensor hits the warning threshold.

Slow leaks are sneaky because the car can still feel “normal” at first. But underinflation increases heat buildup and can damage the tire internally. If you keep driving on a low tire, you can also ruin the sidewall—at which point the tire may no longer be repairable.

If you suspect a slow leak, inflate the tire to spec and monitor it closely. If it drops again, get the tire inspected. A proper repair typically involves removing the tire and patching from the inside (often with a plug-patch combination), not just plugging it externally.

Leaky valve stems or corrosion around the bead

Not every leak comes from a puncture. Valve stems can crack with age, valve cores can loosen, and in areas with road salt, corrosion can develop where the tire meets the wheel (the bead). Any of these can cause gradual air loss.

Bead leaks are more common on older wheels and can show up as a tire that needs air every couple of weeks. If you’ve ever noticed bubbles around the rim when using soapy water, that’s a clue. A shop can often clean the bead area and reseal it, depending on the wheel condition.

Valve stem issues are typically inexpensive to fix, but they’re important. A failing stem can go from “slow leak” to “sudden leak” if it splits, especially in cold weather.

Overinflation (yes, that can trigger warnings too)

While TPMS is mainly about low pressure, some vehicles will warn if pressure is unusually high. Overinflation can happen if you fill tires when they’re hot (right after driving) or if you accidentally inflate to the maximum PSI on the tire sidewall instead of the vehicle’s recommended PSI.

Overinflated tires can ride harshly, wear faster in the center of the tread, and provide less traction on rough or wet surfaces. If you’ve recently added air and the light came on—or the car feels bouncy—double-check the door-jamb sticker and adjust accordingly.

For best accuracy, check and set tire pressures when the tires are cold. “Cold” means the car has been parked for a few hours or driven less than a couple of kilometers at low speed.

TPMS sensor battery failure or sensor damage

Direct TPMS sensors are powered by small batteries that typically last 5–10 years. When the battery gets weak, the sensor may send intermittent signals, or stop communicating altogether. That’s when you may see a flashing TPMS light or a “TPMS system fault” message.

Sensors can also be damaged during tire mounting, by impact (like hitting a pothole), or from corrosion. If you’ve recently had tires installed and the TPMS light started acting up soon after, it’s worth having the sensors checked.

Replacing a sensor usually involves removing the tire from the wheel, installing a new sensor, and then programming it to the vehicle. Some cars auto-learn new sensors after driving; others require a scan tool procedure.

How to check your tire pressure the right way

If the TPMS light is on, the quickest and most reliable next step is to check all four tires with a gauge. Even if the light seems to point to one tire, it’s common for multiple tires to be slightly low—especially after a temperature drop.

Start by finding the correct tire pressure specification. This is usually on a sticker inside the driver’s door jamb. Don’t use the number molded into the tire sidewall—that’s the maximum the tire can hold, not the recommended operating pressure for your vehicle.

Check pressures when the tires are cold. If you have to drive to an air pump, try to keep it short and slow, then add a couple PSI above spec and recheck later when cold, adjusting down if needed. It’s not perfect, but it’s better than running underinflated.

Don’t forget the spare (if your vehicle monitors it)

Some vehicles include the spare tire in the TPMS system. If your spare is stored under the vehicle or in the trunk for years, it can easily be low without you noticing. That can trigger a TPMS warning that seems mysterious because your four road tires check out fine.

If your car has a full-size spare and a sensor, check it periodically. If it’s a compact “donut” spare, it often has a higher recommended pressure than your normal tires, so make sure you’re using the correct number for that tire.

Even if the spare isn’t monitored, keeping it properly inflated is one of those small things that can save your day when you least expect it.

What if your tires are fine but the light stays on?

If all tires are at the correct pressure and the TPMS light remains on, you might be dealing with a sensor issue, a system that needs a relearn, or a vehicle that hasn’t updated yet. Some systems only refresh readings after you’ve driven for a certain amount of time or speed.

Try driving for 10–20 minutes at city/highway speeds. If the light still doesn’t clear, check your owner’s manual for the specific reset or relearn procedure. Some cars have a TPMS reset button; others require using the infotainment menu; others require a scan tool.

Also consider whether you recently rotated tires, installed new wheels, swapped seasonal tires, or had a tire repaired. Any of those can change sensor positions or require the system to relearn which sensor is at each corner.

Resetting the TPMS light: what works (and what doesn’t)

Resetting the TPMS light is only a good idea after you’ve corrected the underlying problem. If you reset without fixing a leak or low pressure, the light may come back—or worse, stay off while the tire continues to lose air.

With that said, there are a few common reset paths depending on your vehicle. The owner’s manual is the best source, but the general patterns below can help you understand what’s happening.

Method 1: Inflate to spec and drive

Many vehicles will automatically clear the TPMS light once all tires are at the correct pressure and the car has been driven long enough for the system to confirm stable readings. This can take anywhere from a few minutes to a full drive cycle.

If you topped up your tires at a gas station and the light didn’t turn off immediately, don’t panic. Drive normally for a bit and see if it resolves. If it doesn’t, recheck pressures with your gauge—sometimes air pumps are inaccurate, and it’s easy to end up a few PSI short.

Also keep in mind that if one tire is significantly lower than the rest, it may have suffered damage. Getting the pressure back up doesn’t always mean the tire is healthy.

Method 2: Use the TPMS reset button or menu option

Some vehicles include a physical TPMS reset button (often under the steering wheel or in the glove box). Others place the reset in the vehicle settings menu. The reset typically tells the car, “These current pressures are the baseline,” especially in indirect TPMS systems.

For indirect systems, the reset is essential after adjusting pressures or rotating tires, because the system needs to relearn what “normal” wheel speeds look like. For direct systems, a reset may simply clear the warning if all sensors report correctly.

If you reset and the light returns quickly, treat that as useful information: either a tire is still low, the system isn’t seeing a sensor, or there’s a real fault that needs diagnosis.

Method 3: Relearn procedure after rotations or sensor replacement

When tires are rotated, some vehicles can automatically detect the new sensor positions, but others need a relearn procedure. This is especially common on vehicles that display pressure at each wheel position. Without relearn, the car may show the wrong tire location as “low,” which can be confusing.

A relearn might involve a sequence of steps like turning the ignition on/off, honking the horn, or using a TPMS activation tool near each valve stem. In many shops, a scan tool handles this quickly.

If you swap between winter and summer wheels that each have their own sensors, you may need a relearn each season unless your vehicle supports multiple sensor sets.

When the TPMS light should change your driving plans

A TPMS light is sometimes a gentle reminder and sometimes an urgent warning. The tricky part is knowing which one you’re dealing with. The light itself doesn’t always tell you how low the tire is—just that it’s below a threshold.

Use your senses and a quick visual check. If the car pulls to one side, the steering feels heavy, you hear a flapping sound, or you can see a tire looks “squished,” don’t keep driving at speed. A tire that’s very low can overheat and fail.

If you’re unsure, stop somewhere safe and check pressures with a gauge. If a tire is very low (for example, under ~20 PSI, or dramatically lower than the others), it’s safer to inflate it and head directly to a shop—or use your spare/tow service depending on the situation.

Flashing TPMS light: treat it as a system problem, not a tire problem

A flashing TPMS light often indicates a malfunction—like a dead sensor battery or a communication issue. Your tires could be perfectly fine, but you’ve lost the safety net of pressure monitoring.

If the light is flashing, it’s still smart to check tire pressures manually. Then plan to have the system scanned and repaired when convenient. You don’t want to ignore a malfunction for months, because you might miss a real low-pressure event later.

In areas with big seasonal swings (or lots of road debris), TPMS is genuinely helpful—so restoring it isn’t just about clearing a light, it’s about keeping a useful warning system working.

TPMS plus other warning lights: take it seriously

If the TPMS light appears alongside ABS, traction control, or stability control warnings, you may have a broader sensor or electrical issue—or you may have a tire problem severe enough to affect wheel speed readings. Either way, it’s not something to casually postpone.

Low tire pressure can reduce traction and increase stopping distance, which can make stability systems work harder. If you’re seeing multiple lights, slow down, avoid aggressive maneuvers, and get the vehicle checked soon.

And if you feel vibration, hear grinding, or notice a burning smell, stop driving and investigate. Those symptoms point beyond simple tire pressure.

How TPMS ties into everyday maintenance (and why it’s worth paying attention)

It’s tempting to think of TPMS as “just another dashboard light,” but it’s closely connected to the rest of your car’s health. Tires are the only part of the vehicle that actually touches the road, so small changes in pressure can ripple into handling, braking, and fuel economy.

Underinflated tires can wear faster on the edges, run hotter, and feel vague in corners. Overinflated tires can wear in the center and feel skittish on rough pavement. Either way, you’re paying for it in tread life and comfort.

Many drivers first notice tire issues when they’re already at a shop for routine service. If you’re visiting an auto center for regular maintenance, it’s a great time to ask for a quick tire pressure and tread check—especially before road trips or seasonal weather changes.

TPMS and tire rotations: avoiding the “wrong tire” confusion

Tire rotations help your tires wear more evenly, but they can confuse TPMS systems that track individual wheel positions. After a rotation, the car might still think the front-left sensor is in the front-left—even if it’s now in the rear-right.

If your vehicle only has a single TPMS warning light, you may never notice the mismatch. But if it displays individual pressures by position, you might chase the wrong tire when the light comes on. That’s why some vehicles need a relearn after rotations.

When you rotate tires, ask whether your vehicle requires a TPMS relearn and whether the shop performed it. It can save you a lot of frustration later.

Why TPMS warnings sometimes show up after other services

Sometimes the TPMS light appears shortly after unrelated work—like suspension repairs, brake service, or tire mounting. That doesn’t necessarily mean the shop caused a problem, but it can happen if a sensor was disturbed, a valve stem was weakened, or a tire bead didn’t reseal perfectly.

If you’ve recently had brake repair or other wheel-adjacent work, and the TPMS light pops on within a day or two, check pressures first. Then, if everything looks good, consider having the sensors checked for damage or a slow bead leak.

The good news is that most TPMS-related issues are straightforward to diagnose with the right tools. The sooner you investigate, the less likely you’ll end up with uneven tire wear or a surprise flat.

Seasonal tires, new wheels, and aftermarket sensors: what to expect

In Canada, seasonal tire swaps are common, and they’re one of the biggest reasons TPMS questions come up. If you have a dedicated set of winter wheels, you might have sensors in both sets—or sensors in only one set.

If your winter wheels don’t have TPMS sensors, many vehicles will show a warning light all winter. That’s not ideal, because you lose the ability to detect a true low-pressure event at a glance. Some drivers tolerate it; others prefer to install sensors so the system works year-round.

If you do install aftermarket sensors, quality matters. A good shop will choose sensors that are compatible, program them correctly, and confirm the vehicle is reading all four (and the spare, if applicable) before you leave.

New tires don’t automatically mean correct pressure

A common misconception is that new tires come “perfectly set.” In reality, tires can be installed at a shipping pressure, or inflated quickly without a careful cold-pressure verification. If your TPMS light comes on shortly after new tires, don’t assume something is wrong with the tire itself—start with a pressure check.

Also, if your new tires have a different load rating or sidewall stiffness than your old ones, the same PSI can feel different. Stick to the vehicle’s recommended pressure unless your tire professional advises otherwise for a specific use case.

After a tire change, it’s smart to recheck pressures a few days later, once everything has settled and temperatures have fluctuated.

Wheel size changes and indirect TPMS quirks

If your vehicle uses indirect TPMS and you change wheel/tire sizes, the system can become less accurate. Different overall tire diameters change wheel speed readings, which can lead to false warnings or missed low-pressure events.

Even with direct TPMS, changing wheel setups can introduce new variables: sensor compatibility, valve stem angles, and the risk of leaks if the wheel and tire aren’t perfectly matched.

If you’re customizing wheels, make TPMS part of the plan from the start. It’s much easier than troubleshooting a persistent light later.

TPMS light myths that keep drivers stuck

“If the light turns off, everything is fine”

Sometimes the light turns off because the tire warmed up and pressure rose slightly. That doesn’t mean the tire is healthy—it just means it temporarily crossed the threshold. If the underlying issue is a slow leak, it will be back.

The best approach is to treat the first warning as a prompt to check all four tires cold. If one tire is consistently lower than the others, you’ve found your suspect.

Tracking pressures over a week can reveal patterns that a single check won’t.

“I filled to the number on the tire, so I’m good”

The tire sidewall number is the maximum pressure the tire can safely hold, not the correct operating pressure for your vehicle. Filling to the sidewall max can make the ride harsh and reduce traction, and it may even trigger warnings on some vehicles.

Always use the vehicle manufacturer’s recommended PSI on the door jamb sticker. That spec accounts for the vehicle’s weight distribution, suspension tuning, and intended handling characteristics.

If you’re towing or carrying heavy loads, check your owner’s manual for any alternate pressure guidance.

“Resetting the light fixes the problem”

Resetting the TPMS light is like turning off a smoke alarm without checking for smoke. If a tire is leaking, the reset just delays the next warning. If a sensor is dead, the reset won’t bring it back to life.

Think of the reset as the final step after you’ve verified pressures and repaired leaks. If the light returns, that’s valuable feedback that something still needs attention.

When in doubt, a manual pressure check beats guessing every time.

Quick “what should I do right now?” scenarios

The light came on while driving, but the car feels normal

Find a safe place to stop and do a quick visual check. If all tires look normal, drive carefully to the nearest place you can check pressure with a gauge. Inflate to the door-jamb spec.

If the light turns off after driving, still recheck pressures cold the next morning. That’s the best way to confirm you’re not dealing with a slow leak.

If one tire keeps dropping, get it inspected sooner rather than later to avoid tire damage.

The light is on and one tire looks low

That’s a “don’t ignore it” moment. A visibly low tire can heat up quickly at highway speeds. If you have a portable inflator, add air and see if it holds long enough to reach a shop safely.

If the tire won’t hold air, or it’s extremely low, use your spare or call for roadside assistance. Driving on a nearly flat tire can destroy it and potentially damage the wheel.

Once repaired or replaced, make sure the shop confirms the TPMS sensor is intact and that the system updates properly.

The light keeps coming back after you add air

This usually means one of three things: a slow leak, a bead/valve issue, or you’re not actually reaching the correct PSI (inaccurate pump gauges are common). Use your own gauge if possible and compare readings.

Mark the tire pressures and check again after 24–48 hours. If one tire drops more than the others, you’ve narrowed the problem down.

At that point, a proper inspection and repair is the fastest path to stopping the cycle of refilling.

Keeping the TPMS light off long-term (without obsessing over it)

You don’t need to be a tire expert to avoid TPMS headaches. A few simple habits go a long way: check pressures monthly, adjust with seasonal temperature changes, and don’t delay investigating repeat warnings.

It also helps to bundle tire checks with other routine services. For example, if you’re already booking an oil change, ask for a quick tire pressure and tread-depth check at the same time. It’s an easy way to catch slow leaks, uneven wear, or nails before they become bigger problems.

Finally, if your TPMS sensors are getting older (especially past the 5–10 year window), be aware that sensor batteries don’t last forever. Planning for sensor replacement during a tire change can be more efficient than dealing with a flashing warning light at random.

A simple mental checklist for TPMS peace of mind

If you remember nothing else, remember this: TPMS is a warning system, not a diagnosis. The light is your prompt to check pressures, look for obvious problems, and decide whether it’s safe to keep driving.

When the light comes on, take a minute to ask: Did the weather just change? Did I recently rotate or swap tires? Do I have a gauge reading that confirms the pressure? Those three questions solve a huge percentage of TPMS mysteries.

And if something feels off—pulling, vibration, unusual noise, or a tire that looks low—trust that instinct. Tires are too important to gamble on, and dealing with the issue early is almost always cheaper and safer than waiting.