How to Install a Tire Pressure Monitoring System

This article explains how to install a cap-based tire pressure monitoring system (TPMS) on your vehicle. It includes options for other types of TPMS, but those are not recommended for home installation.

How to Install a Cap-Based Tire Pressure Monitor

Tire pressure monitoring systems are a vehicle safety technology that prevent you from driving with a flat tire. Some vehicles come with built-in systems, but you can install a tire pressure monitoring system at home.

There are two main types of aftermarket tire pressure monitoring systems (TPMS). One type uses sensors installed inside the tires, and the other type uses sensors built into valve stem caps. You can only install the cap type at home.

1. Before you begin a cap-based installation, confirm that you have the following:

   • Enough sensors for your tires: Most vehicles only need four sensors, but you'll need six if you have dual rear wheels. Make sure the sensors are designed for the air pressure level in your tires.
   • A receiver unit designed for use with the sensors: Most kits come with both sensors and a receiver unit. Make sure the sensors and receiver are compatible.
   • Somewhere to store the old valve stem caps: If you ever need to remove the sensors or switch the sensors to a different vehicle, you'll need the old valve stem caps. Don't lose them.
   • Anti-seize compound: This is optional, and you don't need it to complete the installation. Anti-seize prevents metal sensors from getting stuck on the valve stems.

2. Remove the valve stem caps and store them somewhere safe.

3. If you recently checked the tire pressure, move to the next step. However, check the tire pressure if you haven't in a while. If the tire pressure is low, adjust it to the correct level of inflation before installing the sensors.

   Each car has unique requirements. Check your user's manual, the specifications decal, or the tire sidewalls if you aren't sure how much pressure the tires need.

4. Calibrate the TPMS. Some are easy to calibrate, and other systems can't be calibrated. If you can calibrate your system, set it to the specific amount of pressure your vehicle needs. You might also be able to select the threshold at which the system alerts you. Since some monitors don't show the actual pressure in the tires, it's essential to know what the alert point is.

   If you buy a system that you can't calibrate, select one that's compatible with the amount of pressure in your tires. For instance, if your tires need 35 PSI, but you buy sensors calibrated to 50 PSI, the TPMS alert lights will come on even if the tires aren't under-inflated.

5. Install the sensors. Installing cap-based tire pressure sensors is straightforward. Even if you have no experience working on your car, you won't have trouble. In most cases, all you do is screw on the sensors in place of the valve stem caps.

   Avoid cross-threading the sensors because you need a tight seal for the system to work correctly. Regular valve stem caps don't hold back pressure because the valves do so. However, cap-based sensors depress the valves the same way that any other tire pressure checker does.

   You might want to use a tiny bit of an anti-seize compound when installing the sensors. In some cases, the sensor threads corrode or fuse to the valve stem threads. If that happens, you might not be able to remove the sensors. Make sure the compound doesn't squeeze up into the sensor mechanism.

6. Turn on the tire pressure monitor and verify that it receives a signal from each tire. If it doesn't, go through a troubleshooting procedure to determine the problem.

   Some systems designed for passenger cars may not have a high enough signal strength to work on a long truck, SUV, or recreational vehicle. The system may also fail to work correctly due to low battery levels in the sensor caps.

Move Cap-Based Sensors to New Tires or Vehicle

If you buy new tires or rims or you upgrade your entire vehicle, it's easy to take a cap-based tire pressure monitoring system with you. While in-tire monitors typically have to go with your old car if you sell it, it's a straightforward matter to pop off the sensors in a cap-based system and take the sensors with you. Remove the sensors, replace them with the caps that you saved during the initial installation procedure, and you're good to go.

Swapping a cap-based aftermarket tire pressure monitor system to a new vehicle is just as easy. Install the sensors on the new vehicle, make sure everything is correctly calibrated, and your vehicle will have an aftermarket tire pressure monitor just like that.

How to Install an Internal Sensor TPMS

To install an aftermarket tire pressure monitor that uses internal sensors, release the air from each tire, break the bead on each tire, remove the valve stems, and then replace the valve stems with the pressure sensors.