What is TPMS and Why is it Important?

As mother nature continues to exhibit her hold on our weather during the winter months, your dashboard may be lighting up. The radical changes in temperature outside directly effect the air pressure inside your tires. While the naked eye might not pick-up a low level pressure in a tire, your TPMS sensor will.

Monitoring our automotive systems and alerting us of potential hazards has come a long way with the advancement of technology. Warning symbols that resemble a top-secret sequencing code fill your dashboard today. Any chance you still have that secret decoder ring from your childhood?

One of the systems is the Tire Pressure Monitoring System (TPMS). The TPMS system will warn you of a low-pressure issue with at least one of your tires.  Low pressure in one or more of your tires creates an unsafe driving condition.

What is TPMS?

TPMS monitors air pressure and provides an alert when one or more of the tires drops below 25 percent or more of the recommended pressure for the tires. If the pressure drops below the 25 percent measurement your TPMS warning symbol will illuminated in yellow.

This yellow symbol resembles a horseshoe with an exclamation point in the middle. The symbol represents a cross section of a tire. If this warning light comes on, you should have a professional check your tires and TPMS sensors.

There are Two Types of TPMS Systems – Indirect and Direct


  • Indirect relies on wheel speed sensors. These sensors measure the rate of revolution each wheel is making and can be used by on-board computer systems to compare with each other and to other vehicle operation data.
  • Based on the rate of revolution of each wheel, the computer can interpret the relative size of the tires on your vehicle. When a wheel starts spinning faster than expected, the computer calculates that the tire is underinflated and alerts the driver.
  • Indirect tire pressure monitoring system doesn’t measure tire pressure. Instead, it measures how fast your tires are rotating and sends signals to the computer that will turn on the indicator light when something in the rotation is faulty.


  • Direct TPMS uses pressure monitoring sensors within each tire that monitor specific pressure levels – not just wheel revolution data from the anti-lock brake system. The data is wirelessly sent to a control module where it’s analyzed, interpreted, and, if tire pressure is lower than it should be, transmitted directly to your dashboard where the indicator light comes on until you have it checked out.

Why is TPMS important?

Under-inflated tires can cause some noticeable problems like sluggish handling, longer stopping distances, excessive wear and decreased fuel economy. It also increases the risk of a tire experiencing catastrophic failure and placing you and your passengers at risk for a serious injury.

In response to the number of accidents caused by under-inflated tires, TPMS became standard on all 2008 and newer models. Nonetheless, The National Highway Traffic Safety Association (NHTSA) reports that 12 percent of all passenger vehicles in the U.S. have at least one tire under-inflated by at least 25%.

TPMS and the Weather

Clearly there is a direct relationship between temperature changes and the pressure in your tires. This occurs for either air or nitrogen that fill your tires. When the temperature outside the tire changes, it will affect the pressure inside the tire.

Vehicles that sit outside overnight will be affected more by the colder temperatures. The colder months cause more TPMS warnings than the warmer months because TPMS is designed to warn for under-inflating.

During the winter months your TPMS light may be a nuisance. When the temperature dips overnight there is a good chance your TPMS will come on. You might be tempted to just ignore it. Remember, the TPMS is designed for the safety of the driver and their passengers, and while it may be a slight inconvenience to check, it could save you time and money later.

What should you do if your TPMS light comes on? You should immediately check your tire inflation or have a professional check to ensure your tires are in safe condition. As the saying goes, better safe than sorry. Most tire failures occur because people ignore the warning of their TPMS. There is no way to know without physically checking the tire for a problem. There could be an issue with the tire or a simple pressure adjustment due to the weather conditions.

Best Way to Check Your Tire Pressure

You may not need that secret decoder ring after all. The experts at Tire Discounters can help you with all your routine tire maintenance. Stop by your neighborhood store and ask for a free air pressure check. Our trained technicians will check the pressure on your tires and alert you of any issues. Tire Discounters cares about your safety on the road, make an appointment today!