Tire Monitor System - Prevent Blowouts and Protect Your Drivers, Trucks, and Cargo

What comes to mind when you think of under-inflated tires? A tire blowout? A tedious tire-changing process? Delayed goods?

While these are undoubtedly frustrating, there are even more dangerous consequences.

In fact, on average, there are 11,000 tire-related accidents in the US every year, with 664 fatalities in 2020 alone. This alarming statistic highlights the importance of tire safety and maintenance.

Not only are under-inflated tires risky, but they’re costly too. For every 1psi pressure drop in your tires, your fuel efficiency drops by 0.3%. And let’s not forget about the cost of a tire blowout — including tire change, repair and labor costs — not to mention productivity loss.

You can avoid all of this with proper tire pressure monitoring. No doubt, manually checking tire pressure — stepping out, crouching down, and using a pressure gauge — can be inconvenient, especially for larger vehicles with many tires.

But fortunately, there’s a convenient and effective way of monitoring tire pressure — a Tire Monitor System.

In this blog, you’ll learn

  • Definition of Tire Monitor System (TMS) and how it works
  • Types of TMS
  • Benefits of TMS
  • If you need to install TMS
  • Cost of replacing a TMS sensor
  • Difference between the low-pressure light and TMS light

So, let's dig deep into the world of TMS together and discover how this simple and convenient technology can keep your drivers safe and save you money in the long run.

What is a tire monitor system?

Tire Monitor System, also commonly known Tire Pressure Monitoring System (TPMS), is an electronic system in your vehicle that alerts you when the tire pressure of at least one tire falls dangerously low — which is usually 25% of recommended limit.

Think of TMS as your personal tire watchdog. The system helps drivers maintain optimal tire pressure, which ensures safety, reduces fuel cost, and increases tire life.

Think of it like proactive trailer maintenance. It allows you to set thresholds for temperature and pressure, that way you can make decisions to maintain your trailers before they become beyond repair.

Technically, TMS is supposed to monitor both pressure and temperature and TPMS, a subset of TMS, focuses on pressure monitoring. But, both terms are used interchangeably in the automobile industry, and more often than not, they both refer to pressure monitoring.

To ensure the road safety, the United States government has mandated that all vehicles sold since September 2007 must have a tire pressure monitoring system.

Given the safety and economic benefits and regulatory requirements of TPMS, it's not surprising that the global market for TMS is forecasted to reach $23.67 billion by 2026.

Graph showing the increasing global market for TMS

(Image Source)

You can integrate TMS with telematics solutions for customized requirements and convenience. For example, the CalAmp iOn integrates with the TPMS system from Pressure Systems International, offering benefits such as enhanced visibility, consolidated data, compliance, and analytics.

Integrating TPMS with telematics solutions allows you to track your vehicle's tire pressure from anywhere. It enables complete supply chain visibility, ensuring peace of mind.

Benefits of a tire monitor system

Using TPMS has several benefits, including improved safety, higher fuel efficiency, longer tire lifespan, reduced maintenance costs, and regulatory compliance.

Indirect TPMS overview

Let’s go through these benefits one by one.

Enhanced safety

Proper tire pressure is critical for optimal braking, handling, and stability. Underinflated tires can lead to tire failure, blowouts, and loss of control of the vehicle — which can result in severe accidents.

With TPMS, you can monitor tire pressure and take necessary measures when the system alerts. TMS usually alerts you when the pressure in any tire falls 25% below ‌safe levels.

Improved fuel efficiency

Keeping your tires at the correct pressure improves fuel efficiency, helping you squeeze maximum miles out of the fuel — properly inflated tires can save you as much as 11 cents per gallon on fuel.

Longer tire life

Tires that are underinflated experience uneven wear, leading to a shorter lifespan. TPMS helps you maintain optimal tire pressure, ensuring tires wear evenly, last longer, and save drivers money in the long run.

You can increase the average life of your tires by 4,700 miles by keeping them properly inflated.

Reduced maintenance costs

Properly inflated tires require less maintenance than underinflated tires. With TPMS monitoring tire pressure, you can reduce the frequency of tire replacements and extend your vehicle's overall lifespan.

In other words, having a TMS leads to cost savings in the long run, as you won't need to replace tires as often.

Regulatory compliance

TPMS has become mandatory for all new vehicles since September 2007 in the USA. With TPMS, drivers can ensure compliance with regulations and avoid penalties.

Types of TPMS

Based on the way they measure tire pressure, there are two main types of TPMS: direct TPMS and indirect TPMS.

Indirect TPMS?

If you're looking for a tire pressure monitoring system that won't break the bank, indirect TPMS might be just what you need.

An indirect Tire Pressure Monitoring System, also known as ABS-based TPMS, monitors the relative rotational speed of tires to determine if any of them is under-inflated.

When a tire is underinflated, its diameter decreases, and consequently, the rotational speed increases compared to other correctly inflated tires. Indirect TPMS monitors compares the rotational speed of tires using ABS sensors and detects if any of them is spinning faster than others.

Indirect TPMS working overview

Since indirect TPMS doesn't require additional sensors, such as pressure sensors, it costs less than direct TMPS. But keep in mind that it is less accurate — it can't detect if all tires are underinflated at once.

Another limitation of indirect TPMS is that the system detects low tire pressure only if the difference in rotational speeds of tires is significant.

However, despite the shortcomings, indirect TPMS is a good choice if you are looking for a simple, low-cost tire pressure monitoring system.

Direct TPMS?

Direct TPMS, as the name suggests, monitors tire pressures with the help of pressure sensors installed in each tire. The sensors measure the tire pressure in real time and transmit the readings wirelessly to the vehicle's computer.

The system continuously analyzes the data and alerts the driver through a low-pressure light on the dashboard if it detects a low tire pressure in any tire.

Direct TPMS working overview

Direct TPMS has a significant advantage over indirect TMPS in accuracy — it can detect both low and high pressure accurately.

Unlike indirect TPMS, it can detect underinflation even if all tires are underinflated because the sensors measure the pressure in each tire individually.

Although direct TPMS is a more reliable safety feature, it has disadvantages too.

First, direct TPMS is costly to install and maintain compared to indirect TPMS.

Each pressure sensor can be expensive, and since they are battery-powered, you need to replace them when batteries run out of power.

In short, direct TPMS is a more accurate and reliable option for tire pressure monitoring, but it comes with a higher price tag.

Does my vehicle already have ‌TPMS?

Thanks to compliance requirements, all vehicles sold in the USA after September 2007 have a TPMS. Therefore, if your vehicle was manufactured after this date, it likely has a factory-installed TPMS.

However, if your vehicle was manufactured before the mandated date, you may or may not have a TPMS. In such a case, you can install an aftermarket TPMS.

Do I need to install a Tire Monitor System separately?

Hands down, you must always maintain recommended tire pressure levels in your vehicle to ensure the safety of your drivers and others on the road, not to mention cost savings and increased productivity. So, having a reliable TPMS is a must.

Thanks to safety benefits and compliance requirements, TPMS technology has advanced rapidly — there’re a variety of aftermarket TPMS available in the market for you to choose from based on your needs.

A picture of a car dashboard showing the TPMS icon

(Image Source)

If your vehicle already has a Tire Monitor System, make sure it is working accurately. The last thing you'd want is the TPMS to indicate your tires have safe pressure levels when they haven't, or vice-versa.

Faulty sensors or monitors can lead to inaccurate readings, which could show the wrong results. In such cases, replace or upgrade the existing TPMS, or install a new one.

Installing an aftermarket TPMS is relatively simple, and there are various options available, from basic systems to more advanced ones with additional features.

How much does a TPMS sensor cost to replace?

If you are wondering how much a TPMS sensor replacement would cost, the answer is that it depends on several factors — such as the type of vehicle, the brand of the sensor, and the location of the repair shop.

For different types of vehicles, you may require different quality sensors. For example, heavy-duty trucks and trailers require more robust and durable sensors that can withstand adverse circumstances. Thus, the cost of replacing sensors for these vehicles can be more than for lighter vehicles.

Also, the cost of sensor replacement depends on the size of the vehicle - because the more tires the vehicle has, the more sensors you need.

For example, you might need only four sensors for a light-duty truck, six to ten sensors for a tractor-trailer, and many more for a heavy-duty trailer.

The brand also plays a significant part in the cost of replacing a TPMS sensor. Premium brands offer better durability and accuracy, but they’re often expensive. However, investing in quality sensors can save money in the long run by reducing the frequency of replacements.

A picture of a TPMS sensor

(Image source)

Conducting regular maintenance and inspections of your vehicles' tire pressure and sensors can reduce the cost of TPMS sensor replacement. Also, it helps prevent sensor failures and avoid costly repairs.

Is the “low tire pressure” warning the same as a TPMS?

More often than not, people mistake tire pressure lights and TPMS lights for the same thing. However, both lights indicate different issues with the Tire Monitor System.

The tire pressure light — a horseshoe-shaped light on the dashboard with an exclamation mark in the middle — indicates that one of the tires is significantly under-inflated than the recommended levels.

A picture of the low pressure tire warning symbol

(Image Source)

On the other hand, the TPMS light, typically depicted as the letters 'TPMS' on the dashboard, goes off when there’s a malfunction in the Tire Monitor System, such as a failed sensor or a problem with the monitor.

 Picture of a car dashboard showing the TPMS icon

(Image Source)

When TMS triggers tire pressure light, you must immediately check the tire pressures of all tires with a reliable pressure gauge. If any of your tires have low tire pressure, have them inflated properly before you resume your journey.

You should also look for visible damage, such as punctures, cuts, or bulges. If there is any damage, you must get it fixed or replace the tire immediately.

If everything seems alright — pressure in all tires is normal and no visible damage is there — take the vehicle to a qualified technician to repair the TPMS.

Climate change can be responsible for triggering the tire pressure light — tire pressure will change by about 2% for every 10 degrees Fahrenheit change in air temperature.

­­­When the TPMS light comes on, the first step is to manually check all tires to ensure that they are properly inflated to the manufacturer's recommended tire pressure. Use a reliable tire pressure gauge to accurately measure the pressure.

Even if the low tire pressure light isn't on, check the tire pressure of all tires because now you can't rely on TPMS anymore. If all tires have a safe pressure level, you can drive the vehicle but have the system checked and repaired immediately. Meanwhile, keep checking the tire pressure manually after regular intervals.

Dying or dead batteries of pressure sensors is one of the most common reasons behind triggering the TPMS light. The battery typically lasts for 7 to 10 years, and after that, you need to replace the sensors.

Other common reasons for the TPMS light coming on are

  • a damaged pressure sensor
  • a replacement sensor that wasn’t correctly programmed
  • a problem with the TPMS computer, such as a wiring problem

In any of these cases, you need to find a qualified mechanic to check and repair the system.


Investing in a Tire Monitor System is a wise decision for vehicle and fleet owners — as it not only enhances safety for drivers, passengers, and other road users but also brings about cost savings through increased fuel efficiency and longer tire lifespan.

Direct TPMS is known to provide more precise readings and is considered a more dependable safety feature, despite being more expensive to install and maintain, compared to indirect TPMS.

If you want to have visibility into all your vehicle's tire pressures, CalAmp iOn integrated with Pressure Systems International is ideal. It helps you keep tabs on tire pressures from anywhere, ensuring safety and reducing operational costs.

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