What a faulty tire pressure sensor looks like
A tire pressure monitoring system (TPMS) warns you when a tire is low on air. When a sensor or the system itself has a problem, you usually see one of these signs:
- The TPMS light flashes for about a minute or so after startup, then stays on. Many vehicles use this pattern to signal a system fault rather than low pressure. See why your tire pressure light is flashing.
- The light stays on even though every tire is at the correct pressure.
- One wheel shows no reading, or a dash message such as “TPMS fault” or “check tire pressure system” appears.
- The light comes on and off with no clear pattern.
Exact behavior differs by manufacturer, so check your owner’s manual for what your vehicle’s light pattern means.
Common causes
- Dead sensor battery. Most direct-system sensors have a sealed battery that cannot be replaced separately. See how long a tire pressure sensor lasts.
- Physical damage or corrosion. Tire changes, curb strikes, and road salt can damage a sensor or valve stem.
- A new or swapped wheel or tire. Sensors may not be fitted, or may not have been registered with the vehicle after a rotation or tire change.
- Receiver or module problems. Less often, the fault lies in the vehicle’s control module or wiring rather than a sensor.
- Signal interference or a mismatched aftermarket sensor.
How to confirm it is the sensor, not the tire
- Check all four tires with a reliable gauge when they are cold, and set them to the pressure on the door-jamb placard (not the number printed on the tire sidewall).
- Do not forget the spare if your vehicle monitors it.
- Drive for a short while and see whether the light clears. Some systems need several minutes of driving. If the light stays on, see how to reset your tire pressure sensor.
- If the light still returns, or a particular wheel shows no reading, a shop can read each sensor with a TPMS scan tool and show which one is not responding.
If the light is on but the tires check out, this explanation of false tire pressure warnings covers other possible reasons.
Can you keep driving?
If the warning is a system fault and the tires are properly inflated, the car generally still drives normally, but the monitoring is not working. That means you would not be alerted to a slow leak. Check tire pressure manually and more often until it is repaired, and do not assume the light is a fault unless you have confirmed the pressures. If a tire is actually low, or looks flat, address that first. Low pressure affects handling, braking, tire wear, and fuel economy.
How to fix it
- Inflate and recheck. Rule out low pressure first.
- Relearn or reset the system where your vehicle supports it. Procedures vary by model.
- Replace the failed sensor. A sensor with a dead battery is normally replaced as a unit. It may need to be programmed or registered to the vehicle afterward.
- Repair the valve stem, seals, or wiring if those are the cause.
Because the right procedure depends on make and model, a tire shop or dealer with a TPMS tool is often the simplest route.
What replacement costs
Prices vary widely by vehicle, sensor type, and region. Expect the part to range from modest to fairly expensive for some makes, plus labor for removing the tire from the rim, mounting, balancing, and programming. Ask for a written quote that lists the sensor price, labor per wheel, and any programming or valve service fees. Costs can be lower when the tire is already off the wheel for new tires.
Replace one sensor or all four?
Sensors on the same car are usually the same age, so when one battery dies the others may not be far behind. Replacing only the failed one is fine and cheaper today. Replacing all four at once can save repeat labor charges later, especially if the vehicle is old or you are buying new tires. Ask your shop which approach they recommend for your vehicle.
FAQ
Can I replace a tire pressure sensor myself? Only if you can safely remove and mount the tire and have a way to program the sensor. Most owners leave this to a shop.
Will a faulty sensor cause a failed inspection? Rules vary by state and country, so check your local requirements.
Does a faulty sensor make my tires unsafe? The sensor itself does not change the tire, but you lose the early warning. Keep checking pressures by hand.