What TPMS sensors are and why you might need to replace them
A TPMS sensor (tire pressure monitoring system sensor) is a small electronic device mounted inside or on each of your vehicle's wheels. It measures the air pressure in that tire and sends the reading wirelessly to your vehicle's onboard computer. When pressure drops below a safe level, your dashboard warning light turns on.
You may need to install new TPMS sensors if your current ones have failed, if you've bought used wheels without sensors, or if you're switching to a different set of wheels for the season. Sensors typically last five to ten years before the battery inside them dies. A failed sensor triggers a dashboard light that looks like a tire with an exclamation mark inside it.
Key Takeaways
- TPMS sensors are either screwed directly onto the valve stem (external sensors) or built into the valve stem itself (internal sensors), and the type you have determines how you install replacements.
- External sensors can be installed by hand with basic tools, but internal sensors require removing the tire from the wheel, which usually means a trip to a tire shop.
- After installation, you must reprogram or "relearn" the sensors so your vehicle recognizes them, a step many people skip that leaves the warning light on.
- The cost of professional installation at a tire shop typically ranges from $15 to $25 per sensor, plus the cost of the sensor itself.
Identifying which type of TPMS sensor you have
Before you buy or install anything, you need to know whether your vehicle uses external or internal sensors. External sensors screw onto the outside of your valve stem (the small metal post where you add air). Internal sensors are built into the valve stem itself and sit inside the wheel.
To check, look at your wheel from the side. If you see a small cylindrical object screwed onto the valve stem, you have external sensors. If the valve stem looks like a normal metal post with nothing attached, you have internal sensors. You can also check your vehicle's manual or call your dealership with your vehicle's year, make, and model.
Installing external TPMS sensors yourself
External sensors are the easier type to replace on your own. You will need a socket wrench or adjustable wrench that fits the sensor's base, a new TPMS sensor designed for your vehicle, and the relearning tool or instructions for your specific car (covered in the next section).
First, locate the valve stem on the wheel you're working on. Use your wrench to unscrew the old sensor by turning it counterclockwise. It should come off by hand once you've loosened it. Screw the new sensor onto the valve stem by hand first, then tighten it with your wrench. Do not overtighten — snug is enough. Repeat for each wheel. Once all sensors are installed, you'll need to reprogram them so your vehicle recognizes them.
When you need a tire shop to install internal sensors
Internal TPMS sensors require the tire to be removed from the wheel, which means breaking the seal between the tire and rim. This is not a job for a driveway. A tire technician will use a tire machine to remove the tire, replace the valve stem and sensor as one unit, and reinstall the tire.
The cost at a tire shop is typically $15 to $25 per sensor, plus the cost of the sensor itself (usually $20 to $50 per sensor depending on your vehicle). Some shops charge a flat fee for the whole job. Call ahead and ask for a quote. Many shops will reprogram the sensors for you as part of the installation, but confirm this before you drop off your vehicle.
Reprogramming sensors so your vehicle recognizes them
After you install new sensors, your vehicle's computer does not automatically know they exist. You must reprogram or "relearn" them. The method depends on your vehicle's year, make, and model, and there is no single way that works for all cars.
The most common method is the drive cycle: drive your vehicle at speeds above 20 mph for 10 to 20 minutes. Some vehicles require you to turn the ignition on and off a specific number of times, or to hold down a button on the dashboard. Others need a special relearning tool that communicates directly with the sensors. Check your vehicle's manual or search online for "[your year, make, model] TPMS relearn procedure." If you had the sensors installed at a tire shop, ask whether they performed this step for you.
If you skip this step, your dashboard warning light will stay on even though your sensors are working correctly. Reprogramming is free and takes only a few minutes once you know the procedure for your vehicle.
Buying the right replacement sensors for your vehicle
TPMS sensors are not universal. You need sensors designed for your specific vehicle because they communicate using a frequency and protocol that your car's computer expects. Buying the wrong type will not work, even if it physically fits.
When you order or purchase a sensor, provide your vehicle's year, make, model, and engine size. You can buy sensors from tire shops, auto parts stores, online retailers, or your dealership. Dealership sensors are usually the most expensive but are may provide to be correct. Auto parts stores and online retailers are cheaper but require you to verify the part number matches your vehicle. If you are unsure, call the shop or retailer and read them your vehicle information before you buy.
What to do if the warning light stays on after installation
If your dashboard light is still on after you've installed new sensors, the most common cause is that you skipped the relearning step. Go back and follow the relearn procedure for your vehicle. Drive it, press buttons, or use a tool as needed. The light should turn off once the vehicle recognizes the sensors.
If the light stays on after relearning, one of the new sensors may be faulty, or you may have installed it incorrectly. For external sensors, unscrew the sensor and check that the valve stem itself is not damaged or leaking air. Screw the sensor back on firmly and try relearning again. If the light persists, take your vehicle to a tire shop or dealership. They can scan your vehicle's computer to see which sensor is not communicating and replace it if needed.
Frequently Asked Questions
Can I install TPMS sensors without removing the tire?
Only if you have external sensors. External sensors screw onto the valve stem from outside the wheel and do not require tire removal. Internal sensors are built into the valve stem and require a tire machine to remove the tire, so you cannot install them yourself at home.
Do I need special tools to install external sensors?
You need only a wrench that fits the sensor's base, which is usually a standard size. A socket wrench or adjustable wrench works. You do not need a tire machine or any electronic equipment to physically install external sensors, though you will need to reprogram them afterward.
How much does it cost to have a tire shop install TPMS sensors?
Labor typically runs $15 to $25 per sensor. The sensor itself costs $20 to $50 depending on your vehicle. Total cost per wheel is usually $35 to $75. Prices vary by location and shop, so call ahead for a quote.
What happens if I drive with a failed TPMS sensor?
Your dashboard warning light will stay on, but you can still drive safely. The sensor failure does not affect your brakes, steering, or engine. However, you lose the ability to monitor that tire's pressure, so you should check it manually with a tire gauge and keep it properly inflated.
Can I reuse my old TPMS sensors on new wheels?
Yes, if your old sensors are still working. External sensors unscrew and can be moved to new wheels. Internal sensors are part of the valve stem, so they come with the wheel. If you're buying used wheels with internal sensors already installed, you may need to reprogram those sensors to your vehicle.