TPMS guide
What does a TPMS warning light mean?
A TPMS (Tyre Pressure Monitoring System) warning light means one or more tyres are at least 25% below the recommended inflation pressure. On direct TPMS systems, the vehicle identifies which tyre is low; on indirect systems, only the warning is shown without specifying which tyre. After correcting pressure, the light may extinguish automatically after driving above 40 km/h for a few minutes, or may require a manual reset. TPMS does not detect slow leaks that maintain pressure above the 25% threshold, nor does it detect uneven pressure between tyres (e.g. 2.0 bar vs 2.5 bar recommended — both above the warning threshold).
- A TPMS (Tyre Pressure Monitoring System) warning light means one or more tyres are at least 25% below the recommended inflation pressure.
- On direct TPMS systems, the vehicle identifies which tyre is low; on indirect systems, only the warning is shown without specifying which tyre.
- After correcting pressure, the light may extinguish automatically after driving above 40 km/h for a few minutes, or may require a manual reset.
FAQ
- What does a TPMS warning light mean?
- A TPMS (Tyre Pressure Monitoring System) warning light means one or more tyres are at least 25% below the recommended inflation pressure. On direct TPMS systems, the vehicle identifies which tyre is low; on indirect systems, only the warning is shown without specifying which tyre. After correcting pressure, the light may extinguish automatically after driving above 40 km/h for a few minutes, or may require a manual reset. TPMS does not detect slow leaks that maintain pressure above the 25% threshold, nor does it detect uneven pressure between tyres (e.g. 2.0 bar vs 2.5 bar recommended — both above the warning threshold).
- What should I verify before using this information?
- Use TireFitLab values as a sizing reference, then verify the vehicle handbook, tire placard, rim compatibility, load rating, and physical clearance before fitting.
Direct TPMS vs indirect TPMS
All passenger vehicles sold new in the EU (since 2014) and USA (since 2008) must carry TPMS. Two technologies meet this requirement. Most modern vehicles use direct TPMS; indirect systems are more common on older vehicles and some Japanese-market models.
| Feature | Direct TPMS | Indirect TPMS |
|---|---|---|
| How pressure is measured | Dedicated pressure sensor in each wheel (inside the rim, battery-powered) | No pressure sensor — estimates pressure from ABS wheel speed data (a flat tyre has a smaller rolling radius and spins faster) |
| Which tyre is identified | Yes — the dashboard display identifies the exact corner (FL/FR/RL/RR) | No — the system triggers a general warning without identifying which tyre |
| Warning threshold | 25% below recommended pressure (EU UNECE R64 mandate) | 25% below recommended pressure, but detection is less precise and may lag several minutes of driving |
| Accuracy | High — reads actual pressure in real time, typically accurate to ±0.1 bar | Lower — cannot detect slow simultaneous deflation of multiple tyres; prone to false triggers after tyre rotation |
| Reset procedure after inflation | Drive above 40 km/h for 5–10 minutes, or use dashboard TPMS reset button (if equipped) | Mandatory reset via dashboard menu after every tyre inflation, rotation, or tyre swap |
| Battery life (direct only) | Typically 7–10 years. Sensor must be replaced when battery depletes — cannot be recharged. | N/A — no battery |
| Cost | Higher — separate sensors required for each wheel; spare/winter wheel sets need sensors | Lower — uses existing ABS speed sensors; no additional hardware |
| Regulation requirement | Required for all new passenger vehicles in EU (since 2014), USA (since 2008) | Accepted in some markets as compliant with TPMS regulation; rejected in USA (FMVSS 138 requires direct) |
What the TPMS warning light means
| Warning light state | What it means | Recommended action |
|---|---|---|
| Solid TPMS symbol | One or more tyres at least 25% below recommended pressure. Check and inflate all four tyres. | Stop when safe. Check all tyre pressures with a gauge. Inflate to door-jamb placard values. |
| Flashing TPMS symbol (60–90 seconds then solid) | TPMS system fault. Sensor battery dead, sensor damaged, or system communication error. | Have system diagnosed at a workshop. Warning does not mean tyres are correctly inflated. |
| TPMS symbol disappears after driving | Indirect system: tyre was slightly below threshold; warming up changed rolling radius. | Check pressures cold (after 3+ hours parked). Cold pressure below placard spec triggers this. |
| TPMS symbol after tyre rotation | Indirect system not reset after rotation. Sensors now report wrong corners. | Perform indirect TPMS reset via dashboard menu. Direct systems may auto-learn new positions. |
How to reset the TPMS
Direct TPMS reset
On most vehicles with direct TPMS, no active reset is required after inflating tyres. Inflate all tyres to the door jamb placard values, then drive at or above 40 km/h (25 mph) for 5–10 minutes. The system will read the corrected pressures and extinguish the warning light automatically. Some vehicle models require pressing a dashboard reset button — check your owner manual.
If you switch between summer and winter wheel sets, and both sets have sensors, the vehicle must learn which sensors are on which corner. This auto-learn typically happens during the first drive above 40 km/h (25 mph). Some vehicles require a dealer or workshop tool to programme sensor positions.
Indirect TPMS reset
- Inflate all four tyres to the placard specification (door jamb or fuel cap).
- With the vehicle stationary, locate the TPMS reset button (typically in the glove box, under the dashboard, or in the infotainment menu — consult your owner manual).
- Turn ignition to ON without starting the engine (or use accessory mode on push-button start).
- Press and hold the TPMS reset button for 3–5 seconds until the TPMS warning light blinks three times.
- Release the button. Drive at or above 25 mph (40 km/h) for 20–30 minutes to allow the system to calibrate.
- The warning light should extinguish. If it remains on, the tyre pressures may still be low, or the system has a fault.
Indirect TPMS must be reset after every tyre rotation, tyre swap, or inflation correction. Skipping the reset causes the system to continue using the old speed baseline and may produce false warnings or fail to warn about real pressure loss.
What TPMS cannot detect
| Limitation | Why this matters |
|---|---|
| Slow leak below 25% threshold | A tyre losing 0.1 bar per month will never trigger TPMS if recommended pressure is 2.5 bar. The pressure stays above 1.875 bar (25% below 2.5 = 1.875 bar). Monthly pressure checks are still required. |
| Uneven inflation between tyres | If all four tyres are equally under-inflated (e.g. all at 1.8 bar when 2.5 bar is specified) but above the 25% threshold, TPMS will not warn. Fuel economy and handling are affected, but no light appears. |
| Temperature compensation | Tyre pressure drops approximately 0.1 bar per 10°C temperature drop. On a cold morning after warm-weather inflation, all tyres may briefly read low — some vehicles will illuminate TPMS briefly until the tyres warm up. Always check and set pressure when tyres are cold. |
| Spare tyre | Many spare tyres do not have TPMS sensors, or carry a separate warning. Check spare tyre pressure manually at least every six months. |
| Run-flat tyres | Run-flat tyres can maintain shape even when deflated. TPMS is legally required on vehicles equipped with run-flat tyres precisely because the driver cannot feel the deflation. Always respond to TPMS warnings on run-flat-equipped vehicles immediately. |
Fitting winter tyres: sensor considerations
If you use a separate set of winter wheels, each winter wheel must have its own TPMS sensor for the TPMS warning light to function correctly in winter. Options:
- Sensors in winter wheels — the vehicle programmes itself to the new sensors when first driven above 40 km/h (25 mph). Some vehicles require a dealer tool.
- Sensor transfer — a workshop can remove sensors from summer wheels and re-install in winter wheels. Not recommended: sensor valve stems are fragile and transfer risks damage.
- No sensors in winter wheels — the TPMS light will illuminate permanently, masking any real pressure warnings. This is legal in some markets but negates the safety benefit of TPMS.
Sensors use 315 MHz (USA/Japan) or 433 MHz (Europe) frequencies — incompatible between regions. Confirm sensor frequency matches your vehicle before purchasing.
TPMS sensor battery: when to replace
Direct TPMS sensors contain a non-replaceable lithium battery that typically lasts 7–10 years. Battery depletion is the most common reason for a flashing TPMS warning that persists after inflating tyres. Signs of battery end-of-life:
- TPMS warning light blinks 60–90 seconds then stays solid
- Dashboard shows "TPMS sensor fault" or similar message
- One corner consistently reads 0 bar or a non-plausible value
Sensor replacement requires demounting the tyre to access the rim-mounted sensor.
More tools
- Tire pressure guide
- Run-flat tyre guide
- Tyre puncture repair guide
- Tire rotation guide
- Winter driving tyre guide
- Tire & wheel reference guides
Seasonal check
Planning a long summer drive?
Use the budget and running-cost tools before a trip, especially if the current tyres are worn or the replacement size changes diameter.
What changed
- Reviewed deterministic geometry, load/speed references, sitemap inclusion and localized page shell.