TPMS Light

TPMS Light: Here’s A Complete Guide

TPMS is a specially designed system that will alert you if your tires are low on air. Usually, the TPMS will let you know after your tire losses at least 25% of its total air capacity. Anyhow, you can actually see why this is so important.

Namely, tire pressure is very important when it comes to driving. If you have low tire pressure, you will not be able to control your car properly and that might cause accidents on the road.

On the other hand, having a TPMS to warm you when your tire is losing pressure can actually save you from unwanted troubles.

Now, let’s see exactly how Tire Pressure Monitoring System works and everything that you need to know about it.

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What Does TPMS Light Mean?

What Does TPMS Light Mean


So, if you see any notification on your dashboard that indicates tire pressure is low, it could mean a couple of things.

1) Obstruction

First, the light could indicate that there is a possible problem with the tire. Simply speaking, there might be an obstruction in the tire like a nail or something like a screw. Anyway, you need to check the tire immediately and see for yourself if there is something wrong with it.

2) Neglect

Sometimes the light can indicate the neglect of the tire pressure. Namely, if you didn’t set the tire pressure to manufacturer’s specifications, you will be alerted with the light on your dashboard. Also, you should check the tire pressure every 2 months just to be sure.

3) Drop in Temperature

It happens that tire pressure could drop due to the change in the outdoor temperature. This is not a common thing, especially if you live somewhere where temperature is not dropping drastically.

How Does TPMS Work?

How Does TPMS Work

Simply speaking, the only job that TPMS needs to do is to alert you when your tire is losing air. Now, there are two different types of TMPS. Both of these types have their benefits and downfalls, let’s see them.

Direct TPMS

Direct TPMS


When it comes to direct TPMS, this system is based on the fact that every tire has its own dedicated sensor. This sensor is installed directly within each tire and it is connected to the indicator steam (valve steam).

Now, when your tire losses air, this system will directly send the data to your car’s dashboard and alert you that you have a problem. This is possible because these sensors read the tire pressure correctly and will alert you if there is some air loss.


  • Sensors deliver accurate and precise pressure readings.
  • Batteries that charge the system can last up to 10 years.
  • No need to reset system after you experienced the tire losing air problem.


  • This system is a bit more expensive to maintain if the sensors should be replaced.
  • Sensors can be easily damaged when the tire is installed, so the tech needs to be extra careful.
  • Tools that are requires for maintaining are expensive.

Indirect TPMS

Indirect TPMS


Now, Indirect TPMS is based on the car’s ABS (anti-lock brake system) to measure the correct level of air pressure that is based on the rotation speed.

Simply speaking, if there is one tire that spins faster or slower than other ones, this system will indicate under-inflation. The indirect TPMS has its weaknesses and strengths, so let’s see them.


  • It is less expensive than Direct TPMS system since it doesn’t require any sensors.
  • This system lasts longer than any other system. Lasts as long as the vehicle itself.


  • Sometimes the readings can be inaccurate. This depends on the tire’s size and whether it is worn unevenly.
  • If all 4 tires are low on air pressure, you won’t be alerted since there are no oscillations in spinning rates.
  • You need to reset the system every time you change the tire or inflate it.
  • thumbs-downSometimes you need to drive for a longer period of time before you get the tire pressure alert.

Tire Pressure Light Keeps Coming on

Now, let’s discuss the situation when the tire pressure light keeps coming on. First, there are three different occasions when the light will keep coming on. Let’s see them.

TPMS Light keeps coming – When driving

  • Behavior of the light – Turns up and stays on.
  • Meaning – At least one tire is low on air pressure.
  • You should act – Check tire pressure in all four tires as soon as possible.
  • Is it safe to drive – It is safe to drive, but don’t drive on high speed and be careful when you make turns.

TMPS Light keeps coming – Then it goes off

  • Behavior of the light – Keeps turning on and off then turns off randomly.
  • Meaning – At least one tire has very low air pressure. Possibly to the minimum.
  • You should act – Adjust the tire pressure as soon as possible.
  • Is it safe to drive – It is safe to drive, but make sure to adjust the tire pressure quickly. Therefore, you don’t need to worry about flat tire.

TPMS Light keeps coming – But flashes

  • Behavior of the light – Flashes for a couple of seconds, or it turns on when you start the engine.
  • Meaning – TPMS is not working properly.
  • You should act – Get professional help. Take your car to the nearest auto-mechanics. Also, check your tire pressure manually.
  • Is it safe to drive – First check the air pressure in your tires and then you can drive if everything is normal.
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How does TPMS know which tire is under-inflated?

how does tpms work


Now, before we answer this question, it is important to go back to the direct and indirect TPMS. Basically, if you have direct TPMS, there will be sensors that will indicate if something is wrong with your tire. This means that direct TPMS is absolutely trust-worthy and it can’t alert you of the wrong tire.

On the other hand, there is an indirect TPMS system that measures rotations on your tires and indicates you if some tire is under- performing. Simply speaking, this system measures tire rotations and if one tire is low on rotations, the light will alert you on your dashboard.

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Final Verdict

As we can see, TPMS is quite important for any vehicle. With it, you will be alerted if there is something wrong with your car tires so you can check the pressure. Now, make sure to act when the light flashes on your dashboard since this is a serious thing.

Anyhow, we hope that this article made it clearer for you to understand how TPMS work and what does it do. All in all, check your tires properly.

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