Seeing the light on your car's tire-pressure monitoring system

By Editors on August 6, 2010 8:19 AM

Although it's been required in every new vehicle sold in the U.S. since 2008, the tire pressure monitoring system (TPMS) still seems to remain a mystery to far too many people. According to a study done by Schrader International, one of the main suppliers of these systems worldwide, 46 percent of the owners sampled had no idea what the TPMS icon meant and one out of three didn't know what a tire-pressure monitoring system was. Another troubling find was that while over 95 percent of the individuals queried believed that driving a vehicle with seriously under-inflated tires could impact safety and controllability, only 44 percent admitted to regularly checking pressures.

The TPMS requirement was originally mandated under a provision in the TREAD (Transportation Recall Enhancement, Accountability and Documentation) Act passed in 2000 following a major recall of defective tires that created unsafe driving conditions and led to multiple driver fatalities. By 2008, TPMS had become compulsory across the entire vehicle lineup. Although manufacturers can choose either a direct or indirect type of sensing system, both function by monitoring pressures and illuminating the TPMS dash icon whenever they detect under-inflation of 25 percent or more in any tire -- or when the system itself has a malfunction. The most sophisticated use dedicated displays that provide specific inflation specs on each individual tire.

Should the TPMS warning light go on in your vehicle, Schrader recommends finding a safe place to pull over and visually inspect your vehicle's tires for obvious low-inflation, preferably confirming any suspicions with a tire-pressure gauge if you carry one. Then head over to the nearest gas station with an air pump and bring the tire/tires in question back up to their proper pressure. That information can be found in the owners manual or on a placard located just inside of the driver's door. Generally, the TPMS light will go out automatically after a few minutes, but if it remains on or if you do discover actual tire damage, have the vehicle checked out at your local dealer or a dedicated tire center. For a more complete overview of what TPMS is and how it functions, you can check out Schrader's dedicated help site at: