In-vehicle tire pressure monitoring systems (TPMS) are generally accurate, but drivers should still check their tire pressure manually, according to the AAA.

In a new study AAA engineers evaluated 11 vehicles, 2022-2024 models including sedans, pickups, and SUVs, with “direct” TPMS, which uses air pressure sensors mounted in each wheel.

The main findings were that there were no significant error in displayed tire pressure readings noted for any vehicles evaluated within the study.

The largest percentage difference in reported vs. actual tire pressure was 3.3 percent.

One vehicle did not illuminate the TPMS warning light even when one of its tires was deflated to only 65 percent of the recommended posted pressure, despite the immediate update of pressure readings in the instrument cluster.

“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. But we recommend always having a dependable old-school manual pressure gauge to check them once a month because a tire can be more than 20 percent deflated before it triggers the dashboard warning.”