Tire Pressure Light On? Start Here

A steady light

At least one tire is below the pressure the system expects. On most cars the trigger is a set amount under the placard, so the tire may not look low. The federal tire pressure monitoring rule (NHTSA) sets that amount. Check all four with a gauge, and the spare if it has a sensor.

Many newer cars show the pressure per tire on the dash. If one reads lower than the rest, that is the tire to watch. If all four are a little low, the weather or time since the last top-up is the likely cause.

A light that flashes, then stays on

A light that flashes for a minute or so at startup and then stays on is the system reporting a fault, not low pressure. Common causes: a sensor battery that has died, a sensor damaged during a tire change, or a new sensor the car has not learned yet.

Your tires may be fine. Check them with a gauge anyway, because a faulted system cannot warn you about a real leak. Sensor replacement and relearning is shop work on most cars. It is not a service we list. Ask on the call and we tell you honestly where to take it.

A light that comes on cold mornings and goes off later

Tire pressure falls as the temperature falls. A cool night can drop a tire enough to trip the light, and a few miles of driving warms it back above the line. This is common after the first cool nights of the year.

The fix is the same: set every tire to the placard pressure when cold. A tire set to the placard on a warm afternoon will read low the next cool morning, so check it cold. If the light returns every morning for a week, one tire is probably leaking.

When the light means a leak

A leak looks like this. The light comes back within days of a fill. One tire reads lower than the others every time. You hear a hiss or see a nail head in the tread. Then it is no longer a pressure question. Our slow leak page covers how we find it. Call and we come to the car.

When to stop driving

• The light is on and one tire visibly sags or looks flatter than the others
• You feel a thump, a wobble, or the car pulling to one side
• The light came on suddenly at speed along with a change in how the car drives
• The pressure readout shows a tire far below the others and still falling

In those cases pull over where it is safe, put your hazards on, and do not drive on it. Driving on a low tire can damage the sidewall from the inside and turn a repairable puncture into a replacement. Call Emergency Mobile Tire Repair and tell us what you see.

After a spare install

Compact spares usually carry no sensor. On most cars the light stays on, or shows a dash, until the full-size tire is back on the car. That is expected. Treat it as a reminder that the spare has its own speed and distance limits, printed on the spare, and plan the replacement soon.

What we do on site

We check and set pressure on all four tires, fix valve stem leaks, and find slow leaks at the car. A tread puncture within U.S. Tire Manufacturers Association repair limits is repaired on site. If not, we help with the spare or a replacement where available. Sensor replacement is not a listed service, so ask on the call.