Your vehicle tire pressure monitoring systems (TPMS) are generally accurate, a study conducted by AAA found, but the organization still says you should check your tire pressure manually.
AAA says you should check your tire pressure because they are the only part of your vehicle that physically touches the roadway and having proper inflation is the key to safety and better fuel economy.
“Whether in rain, sleet, snow, or dry conditions, tires are the unsung heroes of your car,” said Greg Brannon, AAA’s director of automotive engineering. “They are designed to work best when properly inflated. Our research found that the pressure monitoring systems that provide data for instrument displays or trigger the amber dashboard warning worked as intended.”
The study conducted by AAA looked at 11 passenger vehicles with model years ranging from 2022-2024. All vehicles included a direct TPMS, which uses air pressure sensors mounted in each wheel. The study found the average difference between displayed and actual tire pressure was between 1.2% and -1.5%. For 5 of the 11 vehicles tested, the TPMS warning light was activated when the tires were underinflated to 75% of the recommended pressure.
Key findings of the study showed that there was: no significant error in displayed tire pressure readings, the largest percentage of difference in reported vs. actual tire pressure was 3.3%, only one vehicle (unnamed make and model) failed to illuminate the TPMS warning light even when one of the tires was deflated to 65% of the recommended pressure.
Recommendations from AAA by the study are for drivers to utilize displayed tire pressures and then to keep the tires inflated to the vehicles posted pressure rather than relying on the TPMS light, TPMS warning light only activates if a vehicles tire pressure is significantly deflated, and for drivers to regularly check their tire pressure.