TPMS Warning Light is Your Car Built-in Safety Check
The TPMS can operate on two detection systems: direct and indirect.
What Does TPMS Warning Light Mean?
When you see the TPMS warning light on your dashboard, it means one or more of your tires is significantly under-inflated. This is your car's built-in safety check telling you to take action immediately.
It's important to understand that the warning light typically only activates when a tire has lost 20% of its recommended pressure (about 0.4 bar on average). At this point, the tire is already considered under-inflated, which can lead to premature wear, poor handling, and increased running costs.
What to Do When Your TPMS Light Turns On?
Find a Safe Place to Pull Over: As soon as it's safe, stop your vehicle. Visually inspect your tires for any obvious signs of a major puncture or a flat.
Check Your Tire Pressure Manually: Use a reliable tire pressure gauge to check all four tires. Under-inflation isn't always visible to the naked eye.
Inflate to the Correct Pressure: Add air until the tires match the recommended PSI (or Bar) listed on the sticker on your driver's side door jamb, inside the fuel flap, or in your owner's manual.
How Does TPMS Work? Direct vs Indirect Systems
Your car uses one of two methods to figure out how TPMS work: a direct or an indirect system.
Direct TPMS
A direct Tire Pressure Monitoring System uses a physical TPMS sensor mounted inside each tire (often as part of the valve stem). This sensor measures the exact air pressure in real-time and transmits that data wirelessly to your car's computer, which then displays the warning on your dashboard.
Indirect TMPS
An indirect TPMS doesn't use pressure sensors at all. Instead, it uses the car's existing Anti-lock Braking System (ABS) wheel speed sensors. It estimates tire pressure by monitoring the rotation speed of your wheels. An under-inflated tire has a slightly smaller diameter, so it will rotate faster than the others. The system detects this difference and triggers the warning light.
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Direct vs. Indirect TPMS
Direct TMPS:
Uses a TPMS sensor in each tire.
Very accurate. Provides real-time pressure data.
Can show individual pressure for each tire.
Sensors have batteries that die (approx. 5-7 years) and need replacement.
More expensive to maintain and replace sensors.
Indirect TMPS
Uses the car's ABS wheel speed sensors.
Less accurate. Estimates pressure based on wheel speed.
Only provides a general low-pressure warning.
No extra maintenance needed.
Less expensive, as it uses existing hardware.
What if the TPMS Light is Flashing?
A solid TPMS warning light means low pressure. But a flashing TPMS light (which typically flashes for 60-90 seconds before staying solid) signals a problem with the TPMS system itself. This could be a dead battery in a TPMS sensor, a faulty sensor, or a communication error. Your tire pressure might be fine, but the system checking it is not working correctly.
Why is My TPMS Light On When My Tires Are Fine?
If you've checked your tires and the pressure is correct, but the light is still on, there are a few common causes:
A sudden drop in temperature: Cold air is denser, which can cause tire pressure to drop and trigger the warning light, especially first thing in the morning.
A faulty sensor: As mentioned, the light could be flashing (or stay solid after flashing) due to a system fault.
The light needs resetting: After inflating your tires, some vehicles require you to manually reset the TPMS light. (See our FAQ below).
TPMS sensor issues can be complex. For a professional diagnosis and service, trust the experts. Find your nearest Michelin dealer now.
Direct vs. Indirect TPMS
Direct TMPS:
Uses a TPMS sensor in each tire.
Very accurate. Provides real-time pressure data.
Can show individual pressure for each tire.
Sensors have batteries that die (approx. 5-7 years) and need replacement.
More expensive to maintain and replace sensors.
Indirect TMPS
Uses the car's ABS wheel speed sensors.
Less accurate. Estimates pressure based on wheel speed.
Only provides a general low-pressure warning.
No extra maintenance needed.
Less expensive, as it uses existing hardware.
What if the TPMS Light is Flashing?
A solid TPMS warning light means low pressure. But a flashing TPMS light (which typically flashes for 60-90 seconds before staying solid) signals a problem with the TPMS system itself. This could be a dead battery in a TPMS sensor, a faulty sensor, or a communication error. Your tire pressure might be fine, but the system checking it is not working correctly.
Why is My TPMS Light On When My Tires Are Fine?
If you've checked your tires and the pressure is correct, but the light is still on, there are a few common causes:
A sudden drop in temperature: Cold air is denser, which can cause tire pressure to drop and trigger the warning light, especially first thing in the morning.
A faulty sensor: As mentioned, the light could be flashing (or stay solid after flashing) due to a system fault.
The light needs resetting: After inflating your tires, some vehicles require you to manually reset the TPMS light. (See our FAQ below).
TPMS sensor issues can be complex. For a professional diagnosis and service, trust the experts. Find your nearest Michelin dealer now.
Frequently asked questions
.
FAQ
Often, yes. After inflating your tires to the correct pressure, some cars require you to drive for a short period for the light to reset automatically. Others have a dedicated "reset TPMS light" button (often under the steering wheel or in the glove box). Check your owner's manual for your vehicle's specific procedure.
While the theoretical lifespan of a TPMS sensor is 5-7 years, they are exposed to corrosion and shocks. If a sensor fails, replacement costs can vary, but you should contact a professional for a quote as it requires dismounting the tire and programming the new sensor.
You should not. The light is on for a reason—your tire is dangerously under-inflated. This leads to premature wear, poor handling, increased fuel consumption, and a high risk of a blowout. You should check your pressure as soon as possible.
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