How to Tell Which Tire Sensor is Bad

Most cars have tire pressure sensors that alert the driver when the tire does not have the right air pressure. With the sensor in place, a driver can quickly tell when the tire is deflated when driving.

Over time, these sensors can go bad, and just like when other parts of a car go bad, there will be signs. Therefore, the question is, if you notice that one of your car’s tire sensors is bad, how do you tell which one is bad?

You can tell which tire pressure sensor is bad by using a digital pressure gauge to ascertain the pressure of each tire or by using a diagnostic tool to scan the car’s TPMS. You can also tell which sensor is bad by filling and releasing the air in the tire simultaneously.

Can Tire Pressure Go Bad?

Yes, a tire pressure sensor can go bad

Like other parts of a car, the tire pressure sensor can also go bad. When this happens, the causes can be attributed to various things with the most common being that the sensor has reached the end of its life span.

Other causes of a bad tire pressure sensor are:

  • Wear and Tear of the Sensor: Over time, the tire pressure sensor can wear out because of how long it has been in use and due to the location of the sensor. Aluminum pressure may have its valve corroding while the rubber sensors are more prone to wear and tear. When this happens, the sensor goes bad and either stops working or starts to malfunction.
  • Wiring Problem: Another cause of a bad tire pressure sensor is the wiring. It is possible that there is a problem with the wiring in the TPMS which could cause more problems in the sensor itself. Although this is a rare cause, it happens. A wiring problem in the sensor could be because an inexperienced mechanic/rewire was allowed to work on the sensor.
  • An Issue with the Tire Pressure Management System: The cause could also be any part of the TPMS, the TPMS has other parts like the brake system. Damage to any of its components may cause it to become ineffective. This damage could be wear and tear, corrosion, etc.
  • Change of Tire: When changing a car tire, the tire sensor can get damaged in the process. This is one reason why someone with the technical know-how should get the job done.

How to Tell Which Tire Sensor Is Bad

Below are how to tell which tire sensor is bad:

Using a Digital Pressure Gauge

You can tell which tire sensor is bad by using a digital pressure gauge. The pressure gauge helps you to check the air pressure in the tire.

After each check, note down the readings on the gauge and compare them to the readings on the dashboard. If there is a difference in one or two of the readings then the pressure sensor is bad.

Using a Diagnostic Tool

The TPMS diagnostic tool will be able to detect if air is leaking or coming into any of the tires. When the tire sensor sends a signal to the diagnostic tool there will be a horn chip which indicates that the sensor is still effective. If there is no chip, however, it means the sensor is bad.

By Filling and Releasing of Air

This method requires that you fill each of the tires with air pressure (recommended) and then slowly release the air, you will of course need to refill the tires in order to be able to drive the car. You should do this one tire at a time.

When releasing the air, you should check the display panel in order to see if the light is still blinking. If there is no alert when releasing the air, the sensor for that particular tire is bad. Although effective, this method can be stressful.

The Car Dash Panel

By checking the Tire Pressure Monitor Sensor (TPMS) indicator which is usually on the car dashboard (U-shaped), you will be able to tell if something is wrong with the sensor, the light will blink.

Checking the car dash panel will not necessarily tell you which of the sensors is bad but it will let you know one or more sensors is bad.

How Much Does It Cost to Replace the Tire Pressure Sensor?

Replacing the tire pressure sensor will cost between $200 to $1000 for all sensors, while the cost of fixing will be somewhere between $10 to $30 for each tire.

Not all mechanics are able to properly replace the tire sensor, therefore you will do well to find a professional to do the replacement. You may also need to reset the tire pressure to clear the warning light. This however depends on the kind of car you drive.

Reasons to Replace a Bad Tire Pressure Sensor

Here are some other reasons for you to replace a bad tire pressure sensor:

  • Air Pressure in the Tire is Low: One reason to replace a bad tire pressure sensor is that the sensor has the responsibility of alerting you when the tire is underinflated, but if you find your tire to be low without being alerted, then the tire pressure sensor is bad and needs to be replaced.
  • Improper Warnings: Another reason to replace a bad tire pressure sensor is if it is giving incorrect warnings. When a tire sensor is bad, it starts giving incorrect warnings, you may be alerted to a flat tire when there is nothing wrong with the tires. Or get an indicator of low tire pressure when the tire was recently inflated.
  • Sensor Warning Light Illuminates: A bad tire pressure sensor will cause the warning light to come on your dashboard. This is usually one of the common signs of a bad sensor. When the light comes on, it is usually an indicator that something is wrong with the sensor. If this happens you should consult a mechanic so proper diagnosis can be done.


Replacing a tire sensor is almost always the solution to a bad tire pressure sensor, therefore, if you are to replace the sensor, get an expert to do it because if done wrongly, the tire sensor may not work.