How to Tell Which Tire Sensor is Bad

VD February 02 2022

Tire Pressure Monitoring System (TPMS) monitors the air pressure in each tire with the help of sensors. Each tire will have a sensor that alerts the Electronic Control Unit (ECU) of your car in case of abnormally high or low air pressure. Its primary purpose is to keep the driver updated with each tire’s condition to maintain optimum balance and traction. 

But no electronic device lasts forever - sooner or later it will fail. And if you notice something wrong with your tires, you need to figure out what's causing it, so it's important to know how to tell which tire sensor is bad. Over time, the sensor can become faulty or damaged due to wear and tear or incompatibility with another component. This can cause the car’s owner to either overfill or underfill a tire which can cause traction problems along with the risk of a puncture.

What is a tire pressure sensor?


A tire pressure sensor is a device that helps to monitor the air pressure in your tires. This can be very important in ensuring that your tires are properly inflated, which can help to improve fuel economy and prevent flats. There are a few different types of tire pressure sensors, but they all work to provide you with information about the air pressure in your tires. Some systems will even allow you to adjust the air pressure in your tires from inside your car. Tire pressure sensors can be very useful, but it is important to make sure that they are working properly. If you notice that one of your tires is low on air, or if the sensor itself seems to be malfunctioning, you should take it to a mechanic to have it checked out.

Bad Tire Pressure Sensor (TPMS) Symptoms

A bad tire pressure sensor (TPMS) can cause all sorts of problems for your car. For one, it can trigger a false low tire pressure warning, which can be annoying and distracting. Additionally, it can cause your car's computer to miscalculate fuel economy and emissions, which can impact your wallet as well as the environment. Finally, a faulty tire pressure monitor system can result in uneven tire wear, which can shorten the life of your tires and potentially lead to a blowout.

So what are the symptoms of a bad tire pressure sensor? Here are a few things to watch out for:

Dashboard warning light


If your TPMS is malfunctioning, it will likely trigger a warning light on your dashboard. This could be a generic "check engine" light or a specific symbol that looks like an exclamation point inside of a tire.

Incorrect tire pressure readings


A faulty tire pressure sensor may give you inaccurate readings of your tire pressure. This can lead you to overinflate or underinflate your tires, which can cause a blowout or other problems.

Uneven tire wearuneven-tire-wear-may-indicate-problem-with-tire-pressure-sensor

If your TPMS is not working properly, it can cause uneven tire wear. This can shorten the life of your tires and potentially lead to a blowout.

If you're experiencing any of these symptoms, it's important to have your car checked out by a qualified mechanic as soon as possible. They will be able to diagnose the problem and recommend the best course of action. In some cases, you may need to replace your TPMS sensor, while in others simply recalibrating the system may suffice. Either way, it's best to get it fixed sooner rather than later to avoid any further issues.

How to Tell Which TPMS Sensor is Bad?

Because of its integration with the ECU and other car programs, detecting the faulty sensor is not difficult. Below are some quick ways you can find the malfunctioning one quickly:

Car Display Panel


Your car display panel will have a tire pressure light that indicates a fault in a sensor or not. With a bad tire pressure sensor, this light will either become illuminated or start blinking.

Air Filling and Releasing


This is a tedious and tiring process but also the most accurate. A faulty tire pressure sensor will not detect the correct air pressure; it will either miscompute it or not monitor it at all. To find the faulty one, you must first fill up each tire up to the manufacturer's recommended tire pressure. 

Once done, release the air from one tire at a time and look at the car display as you do this. The faulty one will not detect the continually lowering pressure or might not read a problem at all. 

Depending on your luck, the faulty tire may be the first one you check, but it can also be the last one. For this reason, you need to make sure you have plenty of time to take care of all four times at the same time. 

How to Tell which Tire Pressure Sensor is Bad? 

Tire Pressure Gauges


Tire pressure gauges are a faster and easier option if you don’t have too much time. However, this solution can’t be used with all cars. Most cars only show a fault in the TPMS and alert you when there is an overfilled or underfilled tire. This means they don’t give individual readings about the tire pressure in respective tires. 

For this reason, only use this when you are sure your car has this feature. 

To start, connect your gauge’s pipe with the valve on each tire. Take each tire’s reading at a time and check it against your sensor’s reading. The faulty tire pressure sensor will give way off task and can be quickly identified. 

Tire Pressure Sensor Replacement Cost

The average cost for a Tire Pressure Sensor Replacement is between $158 and $211 for a single wheel, so if you have a faulty tire pressure sensor on every four wheels, you have to multiply that cost by 4. Depena ding on the type of vehicle you have, the sensor may be located in the tire, wheel, or valve stem. Replacing a sensor is generally a quick and easy job that can be done at home. However, if you are not comfortable working with your vehicle, it is always best to take it to a professional mechanic.

Depending on the severity of the leak, a mechanic may be able to simply replace the tire pressure sensor. In more serious cases, however, the entire tire pressure monitoring system (TPMS) will need to be replaced.


While the two options mentioned above are highly accurate and cheap, there are far easier solutions. It's best to take it to a nearby mechanic or dealership to catch the faulty sensor in a matter of minutes. Most tire stores and workshops will have transmitter detectors that can detect a defective sensor without going through the manual air filling and releasing tasks. Because they are quick and don’t require any unscrewing, they don’t cost too much in labor.