Drivers of newer vehicles have a host of warning lights to alert them to potential vehicle problems. While extremely helpful, this technology can lead to confusion. When those anxiety-inducing lights come on, it may not mean what you think it means. For example, seeing the TPMS (tire pressure monitoring system) warning light does not necessarily mean there is a problem with your tires.

If your car’s TPMS warning light comes on when the temperatures are extremely cold, it may be a simple problem that is easier to fix than you think.

How the TPMS Light Works

The TPMS light is part of the pressure monitoring system that involves sensors that are connected to your actual tires.  The TPMS symbol looks like an exclamation point in parentheses. It lights up when the pressure in one or more of your tires is reduced by around 25%. It may also indicate an issue with the tire pressure monitoring system, such as a dead battery.

There is also a reason the light can come on that is not a sign of trouble, but instead just and indication of the season.

How Cold Temperatures Affect Tire Pressure

Tire pressure can decrease about 1 PSI (pounds per square inch) for every 10 degrees the temperature drops. It isn’t because the air is escaping, but because the air inside the tire is condensing and taking up less space. The effect is temporary because as you drive the tire will heat up, which increases the tire’s pressure.

Additionally, tires tend to lose about 1 PSI per month from seepage of air around the edge of the rim, and even through the tread. Together these factors can cause tire pressure to drop as much as 25 percent below the recommended level. The sensing transmitters inside your tires notice this and trigger your TPMS dash light. If your TPMS light comes on you may not have a problem. You may just need to check your air and bring your tires up to the right pressure.

Don’t Ignore The TPMS Warning Light

It is good to know you may not need to start shopping for tires when you see that light, however that does not mean you should ignore it.  Seeing that light means your tires are below the proper air pressure, which increases the chance of tire failure, compromised handling, improper tire and tread wear, and poor gas mileage. 

Check your tire pressure at least once a month during the winter, and have your technician check your tires to make sure there is not a bigger problem triggering that TPMS warning light.