Air pressure is correct but the TPMS light is still on. Nine times out of ten this is a sensor that hasn't been relearned, a dead sensor battery, or a sensor that simply lost sync with the car.
A TPMS light that won't reset doesn't fail safety inspections in every state, but a flashing light DOES indicate a sensor fault, not low pressure. Don't ignore a flashing light.
Most modern cars require a relearn cycle after inflating, rotating, or replacing tires. Honda, Toyota, Ford and GM each have their own procedure (button hold, drive cycle, or scan tool).
TPMS sensor batteries last 5-10 years and are not replaceable separately. Once dead, the sensor must be replaced. Common on 2010-2016 vehicles right now.
TPMS triggers at 25% below placard. If placard says 35 PSI, light comes on around 26 PSI. Cold weather drop alone can trip it.
Aluminum valve stems corrode where they meet the rim. A broken stem leaks air and the sensor often goes with it.
Many full-size trucks have a TPMS sensor in the spare. If the spare is low, the dash light comes on even if all four are perfect.
| What You Notice | Likely Diagnostic Step |
|---|---|
| Light is solid | Pressure issue or stale data - check all 5 tires and relearn |
| Light is flashing then solid | Sensor fault - one sensor is dead or out of range |
| Light came on in cold weather | Pressure dropped with temperature - top off all tires |
| Light returned days after relearn | Slow leak in one tire or dying sensor battery |
Tell us your year/make and what you tried - we'll tell you the exact relearn procedure or whether you need a new sensor.
Get My AI Repair Report →$5.99 - precise diagnosis for your exact vehicle.
Most cars need a relearn drive (10-20 minutes above 20 mph) or a manual button reset. Some require a scan tool. Until that happens, the system is still showing the old reading.
Honda: hold the TPMS button until two beeps. Toyota: reset button under the steering column with ignition on. Ford: ignition on, hold horn button. GM: requires either the TPMS magnet trick or a scan tool. Always check your owner's manual first.
Not necessarily, but if the sensors are 7+ years old it's wise. Aluminum valve cores corrode and rubber grommets dry out - both leak.
$40-$80 per sensor plus $20-$30 labor each. A full set of 4 typically runs $200-$400 installed at a tire shop.
Yes if pressures are confirmed correct with a gauge. But if a sensor is dead, you lose the warning system - meaning you won't know about a real leak. Repair within a few weeks.
Tire pressure drops about 1 PSI for every 10 degrees F drop in temperature. If you set pressure at 70F summer and it hits 20F, you've lost 5 PSI - enough to trigger the warning.