Seeing the Tire Pressure Monitoring System (TPMS) light flicker on is never a great feeling. Sometimes it is a simple reminder to add air. Other times, it is a sign of a slow leak or a sensor problem that needs attention. Either way, that light is there to protect tire life, fuel economy, and safety. Here is what it usually means and the most common reasons it appears.
What the TPMS Light Means
Your car monitors tire pressure through sensors at each wheel. When pressure drops roughly 25 percent below the recommended level, the warning light comes on. You might see a steady amber light, a flashing light at startup, or a message on the dash that calls out a specific tire. Even a small pressure drop can lengthen stopping distances, reduce traction in the rain, and cause uneven tire wear, so it is worth checking soon after the light appears.
1. Cold Weather or Temperature Swings
Air contracts when temperatures fall. A chilly morning can lower pressure several psi compared to the previous afternoon. That small change may be enough to trigger the light, especially if the tires were already a bit low. If the light appears after a cold snap and then disappears once the day warms, temperature is likely the reason. Setting pressures when the tires are truly cold and matching the sticker inside the driver’s door helps keep the light off, even when the weather changes.
2. Slow Leaks from Punctures or Valve Issues
A small nail or screw in the tread can leak slowly, dropping pressure a few psi per day. Worn valve stems, loose valve cores, or corrosion around the bead can do the same. If you top up a tire and the light returns within a week, suspect a slow leak. Check the tread closely and look for shiny objects. A bubble in the sidewall, a hissing sound, or sealant residue near the valve also points to a leak. Driving on a soft tire creates heat and can damage the inner liner, so a quick repair or plug and patch is the best move.
3. Recently Rotated Tires or Sensor Registration
After a tire rotation, the physical location of each sensor changes. Some cars relearn positions automatically after a short drive. Others need a manual relearn with a tool, or a specific sequence in the vehicle menu. If the light started after a rotation or wheel swap, the system may be confused about which sensor is where, or one sensor did not wake up after the wheels were moved. Proper relearn restores accurate readings and clears incorrect warnings.
4. Dead Sensor Batteries or Failed Sensors
Most TPMS sensors have sealed batteries that last five to ten years. When they weaken, the sensor may send a weak or intermittent signal. A classic clue is a TPMS light that flashes for a minute or so at startup, then stays on solid. That pattern often indicates a sensor fault rather than low pressure. Impact damage during a tire change or corrosion from road salt can also harm the sensor body or valve stem. Replacing the failed sensor and performing a relearn brings the system back to normal.
Keep the Light Off: Simple Habits
- Set pressures monthly when tires are cold, and always match the sticker in the door jamb.
- Recheck pressures when the seasons change, as fall and winter can cause a rapid drop in psi.
- After a tire rotation or new tires, ask for a TPMS relearn so your readings stay accurate.
- Replace cracked valve stems and caps to protect against leaks and dirt.
- Do not ignore a light that returns often. Early repairs save tires and improve safety.
Keep Your Tires Safe and Your Dashboard Clear With Griffin Muffler & Brake Center in Fort Madison, IA
If your TPMS light is on, our team can pinpoint the cause and get you back to confident driving. We set pressures correctly, find and repair leaks, replace failing sensors, and perform the relearn so the warning stays off.
Schedule a visit with Griffin Muffler & Brake Center in Fort Madison, IA, and enjoy a smooth, safe ride with accurate tire readings.