Tire Pressure Monitoring Systems or TPMS sensors are a critical addition to your car. They detect a sudden drop in tire pressure and warn you about it, allowing you to inflate the tires before something awful happens.
Therefore, when any of these sensors go bad, it’s crucial to know which one it is and how to fix it. Here are a few quick ways to tell which TPMS sensor is bad:
- Use a TPMS scanner
- Use a digital pressure gauge
- Fill up air in all the tires and release it
- Visually inspect each sensor
- Take the car to a mechanic
This article will explain each method in detail to help you quickly and easily determine which TPMS sensor needs to be replaced. Read on for more information on these and insights into the tell-tale signs of a faulty TPMS sensor.

1. Use a TPMS Scanner
A TPMS scanner is a specialized tool that can quickly diagnose which sensor is bad. It works by reading the signal from each sensor and displaying the data on a screen. This method is the most accurate way to tell which sensor is faulty, but it does require you to purchase or borrow a TPMS scanner from your local auto shop.
While buying a scanner may seem like an inconvenience, it’s worth ensuring that you’re not unnecessarily replacing good sensors. Also, using a TPMS scanner can help you avoid potential problems in the future by allowing you to catch a defective sensor before it causes damage to your tires or wheels.
2. Use a Digital Pressure Gauge
If you don’t have access to a TPMS scanner, a digital pressure gauge is another quick and easy way to tell which sensor is faulty. You can usually find these at your local auto parts store, and they’re relatively inexpensive.
To determine which tire sensor is bad using this approach, follow these steps:
- Hook the gauge up to the tire valve.
- Check the reading on the pressure gauge.
- Check the reading on the TPMS.
If there’s a significant difference between the reading on the TPMS and the reading on the gauge, then you know that sensor is bad. But if the readings are similar, the sensor likely needs to be reset. Either way, a digital pressure gauge is a helpful tool to have in your arsenal when troubleshooting TPMS issues.
3. Fill Up Air in All the Tires and Release It
If you’re still having trouble pinpointing which sensor is bad, another approach is to follow these steps:
- Check the TPMS sensor readings for each tire.
- Fill up all the tires with air and then release it.
- Check if there’s a change in all of the readings for the tires.
If all of the sensor readings change, all of your sensors are in good shape. However, if a reading remains unchanged, that’s the sensor you need to replace.
4. Visually Inspect Each Sensor
If you’re still unsure which sensor is bad, another method is to inspect each sensor visually.
To inspect your tire sensors for damage, you need these tools:
- Lug nut wrench. Go with the CARTMAN Heavy Duty Lug Wrench from Amazon. It’s made of drop-forged steel and is tough enough to loosen even the most stubborn lug nuts. Besides, it’s corrosion-resistant and highly durable.
- Jack. Get the Sunex 3 Ton Aluminum Lift to lift your car off the ground and provide you with extra stability when working on it. It’s stable, reliable, and comes with a side-mounted handle for easy maneuvering.
- Pliers. These IRWIN VISE-GRIP GrooveLock Pliers are ideal for this task. They have a groove joint design that provides 30% more locking power than other twisting tools, and their slip-resistant teeth grip the work surface securely.
- Crowbar. This Spec Ops Flat Pry Bar is the perfect pry bar for the job. It’s made of heat-treated carbon steel for maximum strength and durability, and its wide, flat head provides greater leverage than other pry bars.
Once you’ve gathered the mentioned tools, follow these steps:
- Place the lug nut wrench on the lug nuts and loosen them.
- Use the jack to lift the car.
- Remove your tire’s valve cap by rotating it counterclockwise.
- Detach the tire from the rim using the crowbar.
- Remove the sensor from the wheel.
- Carefully inspect the sensor for cracks, dents, and other signs of damage.
If there’s any sign of damage, that’s likely your faulty sensor. However, if there are no visible signs of wear, you can repeat the above steps for all of your remaining tire sensors until you find the one causing the issue.
Caution: Always take extra care when jacking up your car or working on sensitive parts. If you’re not comfortable doing this on your own, it’s best to take your vehicle to a mechanic.
5. Take the Car to a Mechanic
If you’ve tried all of the above methods and are still unsure which sensor is faulty, your best bet is to take your car to a mechanic. A mechanic can accurately diagnose and replace any faulty TPMS sensors, saving you the time and hassle of doing it yourself. Besides, it’s always best to let a professional handle potentially risky procedures like this.
General Signs You Have a Faulty TPMS Sensor
Now that you know how you can tell which TPMS sensor is bad, let’s now look at some of the signs that indicate you might have a faulty sensor. It’s crucial to be aware of these signs so you can take action as soon as possible and avoid any potential problems down the road.
TPMS Light Is On
When your TPMS light comes on, it’s usually a sign something is wrong with your car’s TPMS sensor. This sensor monitors the air pressure in your tires, and if there’s an issue with this pressure, the TPMS light will signal to let you know. Common causes of this light turning on include a faulty sensor, a problem with the system’s wires or connections, or simply incorrect tire pressure.
Whatever the cause of your TPMS light turning on, it’s essential to address it as soon as possible. If ignored, a problem with the sensor can cause damage to your tires and other vital components of your car.
The ABS Light Illuminates
Another sign that you might have a bad TPMS sensor is if the ABS light on your dashboard turns on. The ABS relies on the TPMS sensors to function correctly, so if a sensor is damaged or not working correctly, it can trigger the ABS light.
ABS stands for the anti-lock braking system — a safety feature that prevents your brakes from locking up. If you notice that the ABS light is illuminated, it’s crucial to take your car to a mechanic right away to get it checked and repaired. By doing so, you’ll ensure your vehicle is always in good working condition and is safe to drive.
The Steering Wheel Is Jerky
Another possible sign of a faulty TPMS sensor is if the steering wheel becomes jerky or unresponsive when you’re driving. This can be due to a gradual loss of air pressure in your tires, which can cause uneven wear and damage to the tire. If this happens, it’s essential to get your car checked by a mechanic as soon as possible so any problems with your TPMS sensor can be detected and repaired.
Incorrect Alerts on Tire Conditions
Besides causing issues like the ones mentioned above, faulty TPMS sensors can also cause false alerts about the condition of your tires. For example, you might get a warning that says your tire is low on air when it’s fine, or you might get an alert that says your tire is OK when it’s low on air.
Either way, these false alerts can be frustrating and cause you to waste time and money. If you’re constantly getting false alerts from your TPMS system, it’s good to have the sensors checked to see if they’re working correctly.
Increased Fuel Consumption
If you notice that your fuel consumption has increased, it might be due to a faulty TPMS sensor. When a sensor is damaged or not working correctly, you may not know if your tires are in bad shape, hurting gas mileage. Generally, the condition of your tires has a significant impact on your car’s fuel efficiency.
If your tires are low on air, they won’t roll as smoothly, so your vehicle will have to work harder and use more fuel.
Low Air Pressure in the Tires
Another sign that your TPMS sensor might be faulty is if you notice low air pressure in one or more of your tires. This could result from a damaged sensor, or it may be due to a slow leak in one of your tires that you haven’t noticed yet.
To prevent this from happening, it’s essential to regularly check the air pressure in your tires and make sure they’re inflated to the proper level. You should also have your tires inspected by a professional if you notice any unusual wear or tear. Also, ensure your sensors are working to avoid any future issues.
How to Replace a Faulty Tire Pressure Sensor
A faulty TPMS sensor will eventually need to be replaced. In most cases, you’ll need to take your car to a mechanic or tire shop to have the sensor replaced. However, if you’re comfortable working on your vehicle, you may be able to replace the sensor yourself.
To replace a faulty tire pressure sensor, follow these steps:
- Locate the defective tire pressure sensor.
- Remove the old sensor from the tire.
- Insert the new sensor into the tire.
- Screw on the cap to close the valve stem.
- Reset your car’s computer system.
- Test if the new sensor is working correctly.
Here’s a video tutorial that may come in handy when replacing your TPMS sensor:
Caution: Make sure you know how to safely use them before attempting to replace your tire pressure sensor. Incorrectly replacing a tire pressure sensor can damage your car or cause serious injury.
In Conclusion
The tire pressure sensor is an integral part of your car’s safety system, but it can sometimes cause issues. If you’re experiencing any symptoms such as false alerts, decreased fuel efficiency, or low air pressure in your tires, it may be time to have your TPMS sensor checked.
Luckily, if the sensor is faulty, it’s usually possible to replace it yourself. Just follow the steps outlined above, and you should be able to replace your TPMS sensor in no time. However, it’s always best to consult with a professional if you’re not comfortable working on your car.