If your vehicle is showing tire looks visibly flat or low on air, here are the most likely causes and the parts you'll need to fix each one.
A sharp object has pierced the tire tread, causing a slow or rapid air leak. This is the most frequent cause of a flat tire.
The valve stem core is loose, or the rubber seal at the base of the TPMS sensor has degraded. This often happens if the TPMS service kit isn't replaced during new tire installation.
Corrosion on the wheel rim or improper cleaning prevents the tire from sealing perfectly against the wheel, allowing air to escape slowly.
Hitting a severe pothole or curb can bend or crack the wheel, breaking the airtight seal with the tire.
The side of the tire has been slashed, bubbled, or blown out due to impact, severe age, or driving on it while severely underinflated.