Bad TPMS Sensor? Dead Giveaway Signs Of A Needed TPMS Replacement

Tire pressure directly affects your car’s mileage, comfort, and overall riding experience. TPMS sensors help you maintain control but are also prone to failure.

So how to tell which TPMS sensors are bad? You can manually check each tire, take help from a handheld tool, or simply visit your mechanic to get things right.

The following write-up will take a detailed look at the most convenient options for you.

A Brief Look at TPMS and How it Helps You

TPMS – Tire Pressure Monitoring System – is one of the most convenient and underrated technologies in any car.

It’s a comprehensive system that uses sensors installed in each tire of your car to keep an eye on tire pressures.

In case of any deviation from the norm (under or over-inflated tires), the system informs you through a prompt on the dashboard.

If you are an experienced driver, you must know how important it is to keep your tires properly inflated.

Overinflated tires can make your ride harsh and noisy. They also offer low traction and can quickly damage your tires.

If you keep your tire pressure high, then you’ll have an uncomfortable ride and will be regularly spending money on new tires.

Similarly, underinflating your tires can also cause several problems. You’ll be experiencing low response which can hinder the performance of your vehicle and increase its fuel consumption.

Underinflated tires are also bad from a safety perspective. Underinflated tires don’t respond well to potholes and other common hazards on the road, which can sometimes put you at a risk.

A functioning TPMS can help you avoid all these issues. 

It always ensures that all your tires are properly inflated and immediately informs you when there is an issue. Naturally, the sensors on the tire are extremely important for the system.

They are mostly exposed to environmental and physical elements, which can cause them to go bad.

What Causes TPMS Sensors to Go Bad?

Before discussing how to tell which TPMS sensors are bad, it’s important to have a general idea of why that happens.

As stated before, TPMS sensors are located at the tires and get exposed to various deteriorating elements. Moreover, you can also damage them when changing tires if you are not too careful.

Some of the most common reasons why TPMS sensors go bad are:

  • Faulty battery
  • Sensor damage while changing the tire or any other reason
  • Worn out sensor seals or gasket
  • Corrosion in the valve stem

The Giveaway Signs that Show Your TPMS Sensors Need Replacement

TPMS sensors generally last for years, so you might forget about checking them.

However, there are some giveaway signs that show that it’s time to see if all your sensors are operational or not. Some of the most common signs that indicate the need for replacing your TPMS sensors are:

1. TPMS Warning Light

Your car’s ECU is quite capable and can generally inform you when the TPMS sensors fail. You’ll see the TPMS warning light on your dashboard and can then proceed to get it checked.

2. Incorrect alerts or warnings

Another obvious sign that you need to check your TPMS sensors is an incorrect warning. Once or twice are fine because the air in your tires might get compressed in winters.

However, frequent warnings with no basis show that the TPMS sensors are not working properly.

3. Underinflated tires

This is related to the previous point. You might see that your tires are underinflated but don’t get any warning. You’ll have to investigate why you didn’t get a warning when your tires started to lose pressure.

4. Car getting uncharacteristically difficult to control

The tire pressure can directly affect your riding experience. If you see that your car is getting uncharacteristically difficult to control, then it might be because your tires are underinflated.

If that’s the case, then ask yourself. Why didn’t you get an alert?

5. Increased fuel consumption

Another thing that gets affected by your tire pressure is your car’s fuel consumption. If you notice that the car is consuming more fuel but can’t solve the problem, then check your tire pressure.

If they are not optimal, then it means that your TPMS failed to notify you.

How Do You Know Which Tire Pressure Sensor is Bad?

Replacement is the only viable way forward in case of a faulty TPMS sensor. But the question is how to tell which TPMS sensors are bad. You can obviously replace all four, which is also recommended in many cases, but that would mean a significant expense.

Luckily, there are several ways to find a bad TPMS sensor.

1. TPMS Scanners

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This handy scanner is one of the easiest ways to spot a faulty TPMS sensor.

Generally, auto technicians and mechanics have and can quickly identify the problematic sensor. The right TPMS diagnostic tool and reader can give you details like the battery status, voltage issues, and much more in a few simple steps.    

2. Manual Air Filling and Releasing

This is a time-consuming process but doesn’t require you to visit the mechanic or buy any new diagnostic tool. All you need to do is manually fill the air in your tires to their optimal pressure. Check out if the TPMS of your car gives an ok report, and proceed to release the air from each tire sequentially.

All you’ll need to do will be to check the dashboard after releasing the air from each tire. The tire with the wrong sensor won’t give you any warning, so you’ll know which one needs replacement.  

3. Monitoring Tire Pressure Digitally

For cars that digitally show the pressure in each tire, you can use this method. It’s very similar to manually release the air but is not as time-consuming.

Use a digital pressure gauge to check the tire pressures and note them down. After that, check the pressures your TPMS shows on the dashboard.

The tire with a different reading has a faulty sensor. Isn’t that simple?

Replacing a TPMS Sensor. How to Get Started?

There is no point in learning how to tell which TPMS sensors are bad if you are planning to get them replaced at a tire shop. They would have done it for you.

Replacing a TPMS sensor is a pretty straightforward process, and you can easily do it at home.

All you need to do is to follow a few simple steps.

Step 1: Prepare the Wheel

Naturally, you’ll have to remove the wheel with the faulty sensor and deflate it before starting. With the right tools, you can remove the valve core and the tire will automatically deflate or manually release the air, which is relatively time-consuming.

Step 2: Break the Bead of your Tire

The next step is to break the bead of your tire. There are several ways to do it even if you don’t have the right machine with you.

The simplest method that works like a charm is to use a combination of a scissor jack and a wooden block.

Put the block on the sidewall of your tire and slide it under your car. Set the jack on your block and proceed to lift the car as you normally do. In this case, the force will be directed downward to help break the bead.

Step 3: Unscrew the Old TPMS Sensor

Once you’ve broken the bead, you’ll easily be able to see the TPMS sensor right behind the air inlet. Unscrew the old TPMS sensor and remove it. Make sure that the sensor doesn’t fall in the tire, as it would be difficult to get out.

Step 5: Attach the New Sensor to Your Tire

Use the same process to screw the new TPMS sensor on your tire. Your sensor will have a new washer and nut, so make sure to use that even if the older one seems all right.

Step 6: Prepare and Attach your Tire

Put your tire back on the bead and reinflate it to the appropriate pressure. Once you are done, attach it back to your car and you are almost done.

Step 7: Activate Your TPMS Sensors

You’ll have to reprogram your car’s TPMS to accept the new sensors. For that, you’ll need to plug the diagnostic tool in your OBD2 port and follow the instructions.

There are some aftermarket TPMS relearn tools as well that are very simple to use. You can also visit a mechanic to get it done at very minimal charges.

The Total Cost of Replacing a TPMS Sensor

It all depends on the model and make of your car along with the sensor you select. There are additional costs as well if you decide to get it replaced at a workshop instead of doing it yourself. 

Generally, the total cost to replace one sensor can go as high as $300 in some cases.

Final Thoughts on How to Tell Which TPMS Sensors are Bad

The Tire Pressure Monitoring System (TPMS) has simplified the process of maintaining your tires.

With a functioning TPMS, you don’t have to worry about keeping an eye on your tire pressures. You’ll be automatically informed when needed.

While you can still drive your car with a faulty TPMS sensor, it’s never recommended. Improper inflation in your tires can lead to several issues and cause safety concerns as well.

That’s why you still have to regularly check your tire pressure to ensure that the TPMS is functioning optimally.  


Dean Alvarez, TireForge Head Author

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