The TPMS System: Its Purpose and Benefits

Written by

CarParts.com Research Team

Automotive and Tech Writers

Updated on March 17th, 2025

Reading Time: 4 minutes
Summary
  • The tire pressure monitoring system (TPMS) warns you about underinflated tires.
  • TPMS sensors measure tire air pressure and send their readings to the TPMS control unit.
  • A direct TPMS has sensors in the tire that directly measure air pressure, while an indirect TPMS uses the wheel speed sensors.
  • Underinflated tires reduce fuel economy, handling, and braking. They also wear out faster and are less safe to use.
  • The TPMS warning light can indicate different issues depending on how it illuminates.
  • The “Check TPMS” and “Service Tire Monitor System” messages indicate serious issues.
  • If the underinflated wheels aren’t excessively low in pressure, you can drive for short distances, preferably to a repair shop.

Your vehicle has many systems that watch the state of various parts. If one or more parts wear out or fail, the relevant system warns you, allowing you to fix the issue and restore your vehicle’s performance. The tire pressure monitoring system (TPMS) is the one responsible for keeping an eye on the tires.

What Is the TPMS?

But what is the purpose of the TPMS system? Simply put, the tire pressure monitoring system warns you if one or more tires have lost too much inflation.

Underinflated tires are a problem you shouldn’t ignore. They cause various issues with the vehicle’s handling, braking, and fuel economy. Furthermore, underinflated tires wear out and heat up faster.

The TPMS tracks the pressure level for each tire. If the tire pressure drops below the safe level, the system warns you about the problem. It helps keep you safe and ensures your vehicle maintains its road performance.

How Does TPMS Work?

TPMS sensors serve as the eyes of the tire pressure monitoring system. The small sensors measure air pressure inside the tires and transmit their readings to the TPMS control unit.

TPMS are either direct or indirect types. Each type uses its TPMS sensors differently. Let’s take a look at each TPMS type:

Direct TPMS

In a direct TPMS, the tire pressure monitoring system sensors are in the tires. Their location enables them to take direct readings of the air pressure in the tires. However, direct TPMS sensors cost more than indirect sensors.

Indirect TPMS

An indirect TPMS doesn’t have specialized sensors dedicated to monitoring tire pressure. Instead, it indirectly measures tire air pressure by checking the readings from the wheel speed sensors.

Tire air pressure affects the tire’s diameter. The air pushes against the inner parts, helping the tire maintain the dimensions specified by the manufacturer. A drop in air pressure reduces the force applied to the tire, altering its diameter slightly. The change in the tire’s diameter causes the underinflated tire to spin at a different speed.

Wheel speed sensors measure how fast the wheels spin. When one of the sensors detects a change in the rotational speed of the wheel it monitors, it transmits a warning to the TPMS control unit. The control unit warns you about the possible decrease in the tire pressure.

What the indirect TPMS lacks in precision, it compensates in terms of cost. It’s more affordable than the direct TPMS while providing acceptable accuracy for general use.

Why Do You Need to Perform TPMS Maintenance?

There is no preventative maintenance for TPMS-related issues. However, if the TPMS warns you about underinflated tires, correct the tire pressure issue at the earliest possibility.

Here are some of the most important reasons for regular TPMS maintenance:

Fuel Economy

Low tire pressure makes the tire more resistant to rolling. That means an underinflated tire covers a shorter distance than a properly inflated tire despite receiving the same amount of torque.

The vehicle must burn more fuel to spin the underinflated tire faster, compensating for the higher rolling resistance. The increased fuel consumption reduces the overall fuel efficiency.

Tire Service Life

Tires are designed to roll on their apex. They can wear out faster if they roll on a less durable part, such as their edges.

Unfortunately, underinflated tires might roll on their edges instead of their apex. They’ll wear out faster, shortening their lifespan.

The TPMS system helps remind you to fix underinflated tires, extending their service life.

Road Safety

Underinflated tires make handling and braking more difficult. They’re also more likely to wear out faster or even overheat. An overheated tire might have a blowout.

TPMS reduces these risks by warning you about low tire pressure.

Vehicle Performance

Correctly inflated tires perform better than underinflated tires. Their treads grip the road surface better, improving traction and braking.

The TPMS keeps you apprised about the air pressure levels of your vehicle’s tires.

Common TPMS Warnings

If the TPMS detects low tire pressure, it turns on the tire pressure warning light on the dashboard. Also called the TPMS warning light, its icon resembles the outline of a flat tire that partially encloses an exclamation mark.

A steadily lit TPMS warning light indicates that the air pressure inside one or more tires has dropped below the safe level.

If you see the TPMS warning light illuminate, stop driving. Park your vehicle somewhere safe and check each tire with a tire pressure gauge. If you find underinflated tires, inflate them to the proper PSI.

Flashing TPMS Warning Light

The TPMS warning light flashes to warn about a problem in the system. Check the tire pressure sensors for issues like inconsistent air pressure readings. You might also want to inspect the TPMS sensor battery.

TPMS Warning Light Flashes Before It Steadily Illuminates

In some cases, the TPMS warning light might flash at first before it illuminates steadily. Check the pressure of all four tires. If you find an underinflated tire, inflate it to the correct air pressure level. Do the same for the spare tire if you keep one in your vehicle.

Does the TPMS warning light still flash after inflating the tires? One of the TPMS sensors might have failed. You’ll need to find and replace it.

Check TPMS Message

The Check TPMS message typically signifies an issue unrelated to tire pressure, such as a sensor malfunction or a dead sensor battery. Diagnosing and fixing the issue usually requires professional expertise to identify and replace the faulty part.

Service Tire Monitor System Message

The “Service Tire Monitor System” warning indicates that at least one of the TPMS sensors isn’t getting detected.

Can You Drive Safely Despite the Service Tire Monitor System Message?

It depends on the air pressure in the tires. Check the tire air pressure on all tires. If they’re not excessively low, you can probably travel safely for short distances. However, go to an auto service center immediately.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.