Owner decision guide
Tire-pressure light flashing, then staying on
A flashing TPMS light usually signals a monitoring-system fault; a steady light usually signals low pressure. Check every tire cold with a gauge either way, then diagnose sensors or relearn requirements if pressures are correct. Before acting, check Cold pressure in all four tires and spare if monitored, Placard pressure, not sidewall maximum, Recent tire rotation or wheel replacement, Sensor age and seasonal temperature change. Record the exact condition, since temperature, speed, load and warning status all change the diagnosis. The sections below break this down further: reading the light, system faults, check pressures manually regardless, temperature effects. This is rated soon risk: Stop before driving if a tire is visibly deflated, damaged, hot, vibrating, or losing pressure quickly. 4 related questions are answered separately below. Reviewed under this site's evidence-first standard, sourced to NHTSA vehicle safety and recall guidance, with related warning lights guides linked at the end.
Evidence first
A tire pressure light that flashes for roughly a minute at startup and then stays solid is reporting a fault in the monitoring system itself, not low pressure. A light that comes on solid without flashing is reporting low pressure in at least one tire.
Confusing the two leads people to add air to tires that are fine, or to assume a system fault when a tire is genuinely low.
Reading the light
The distinction is consistent across most vehicles.
- Solid from startup: at least one tire is below the threshold
- Flashes about 60 to 90 seconds then goes solid: system malfunction
- Comes on while driving: pressure dropped, possibly a puncture
- Comes on cold mornings and clears later: normal thermal variation, but the tires are probably low
System faults
A flashing light has a short list of causes.
- A sensor battery at end of life: these are sealed units, typically lasting several years
- A sensor damaged during tire service
- New tires or wheels fitted without sensors, or without the system being relearned
- After a tire rotation on a system that requires a relearn procedure
- A spare fitted that has no sensor
- Corrosion at the sensor stem, common where roads are salted
Check pressures manually regardless
The monitoring system does not replace a gauge. Federal requirements set the warning threshold well below the recommended pressure, so a tire can be meaningfully underinflated without triggering the light.
Check with a gauge when the tires are cold, before driving, or at least three hours after, and set to the figure on the driver's door jamb placard, not the number on the tire sidewall, which is the tire's maximum instead of the vehicle's specification.
Temperature effects
Tire pressure falls as temperature drops, which is why the light commonly appears on the first cold morning of the season across several tires at once.
That is normal physics, not a fault, but it does mean the tires were at the low end already. Set them to specification with a gauge, not waiting for the light to clear on a warm afternoon.
What to check before acting
| # | Check | Why it matters |
|---|---|---|
| 01 | Cold pressure in all four tires and spare if monitored | Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis. |
| 02 | Placard pressure, not sidewall maximum | Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis. |
| 03 | Recent tire rotation or wheel replacement | Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis. |
| 04 | Sensor age and seasonal temperature change | Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis. |
Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis.
Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis.
Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis.
Record the exact condition; differences in temperature, speed, load and warning status change the diagnosis.
Safe sequence
What to do next
| Step | Action |
|---|---|
| 1 | Measure pressures before driving or after a three-hour rest |
| 2 | Inflate to the door-jamb placard value |
| 3 | Drive the manufacturer-specified relearn cycle if applicable |
| 4 | Scan sensor IDs and battery status if flashing continues |
- 1
Measure pressures before driving or after a three-hour rest
- 2
Inflate to the door-jamb placard value
- 3
Drive the manufacturer-specified relearn cycle if applicable
- 4
Scan sensor IDs and battery status if flashing continues
Avoid making it worse
What not to do
- Do not inflate to the tire sidewall maximum
- Do not ignore a visibly low or damaged tire
Stop before driving if a tire is visibly deflated, damaged, hot, vibrating, or losing pressure quickly.
Source and scope
Common questions
Why is my tire pressure light flashing?
A light that flashes for about a minute at startup and then stays solid indicates a fault in the monitoring system itself. Commonly a sensor battery at end of life, a damaged sensor, or a needed relearn after service.
Does the light mean a tire is flat?
A solid light means at least one tire is below the warning threshold, which is set well below the recommended pressure. Check all four with a gauge, and inspect for a puncture.
Why did the light appear on a cold morning?
Pressure falls with temperature, so the first cold morning of the season commonly triggers it. That is normal, but it means the tires were already at the low end. Set them to specification with a gauge.
Which pressure should I use?
The figure on the driver's door jamb placard, checked cold. The number on the tire sidewall is the tire's maximum, not the vehicle's specification.