MotR
🔵 Drive with Caution

TPMS Warning Light: Tyre Pressure Explained

The tyre pressure monitoring system light warns that one or more tyres are significantly under-inflated. Under-inflated tyres are a leading cause of tyre blowouts and contribute to poor handling, increased fuel consumption, and faster tyre wear.

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Person checking UK car tyre pressure with gauge on a residential driveway — TPMS warning light guide
What it means

What This Warning Light Means

The TPMS warning light (a cross-section of a tyre with an exclamation mark) illuminates when one or more tyres drops 25% or more below the recommended pressure. Tyre Pressure Monitoring Systems have been mandatory on new cars sold in the EU (and therefore UK) since November 2014. Two types exist: direct TPMS uses pressure sensors inside each wheel that transmit wirelessly; indirect TPMS uses the ABS wheel speed sensors to detect a smaller (therefore faster-rotating) under-inflated tyre. If the TPMS light flashes for 60–90 seconds then remains solid, this typically indicates a sensor fault rather than low pressure.

Severity & action

How Serious Is It — and What To Do

🟡 Act Promptly — Check Pressure Immediately

Check tyre pressures at the earliest opportunity — most petrol stations have air compressors. A tyre at 25% below recommended pressure (the TPMS trigger point) affects handling and braking significantly. Driving on a visibly flat tyre risks sudden tyre failure at speed, which can cause loss of vehicle control.

Can drive with caution

Check pressures immediately and inflate to the correct specification (found on a sticker inside the driver's door jamb or in the handbook). Drive slowly and carefully to the nearest air compressor. If a tyre is visibly flat, do not drive on it — use the spare or call breakdown. A completely flat tyre driven on damages the tyre and potentially the wheel.

Stop immediately if…

Stop immediately if you feel the steering pulling strongly to one side (possible rapid pressure loss or blowout in progress), hear a flapping or thumping noise from a wheel, or if the vehicle feels unstable. A tyre blowout at motorway speed is extremely dangerous — ease off the accelerator gradually and steer to the hard shoulder.
Common causes

Common Causes

Genuinely low tyre pressure — the most common cause. Tyres lose approximately 1–2 PSI per month naturally; seasonal temperature changes also affect pressure significantly
Puncture — a slow puncture from a nail, screw, or damaged valve causes gradual pressure loss. A rapid pressure loss suggests a blowout or severe tyre damage
Seasonal pressure change — cold weather causes tyre pressure to drop (roughly 1 PSI per 10°F/5.5°C temperature drop). Winter TPMS illumination after a cold snap is very common
Recently fitted tyres or wheels — if tyres or wheels were replaced, the TPMS sensors may not have been calibrated or relearned for the new fitment
Faulty TPMS sensor — battery-powered sensors last 5–10 years. A dead or damaged sensor triggers the flashing TPMS light
Corroded sensor valve stem — the sensor valve stems corrode over time, particularly on alloy wheels, causing sensor failure or air leaks
Wheel change without sensor transfer — if winter wheels without TPMS sensors are fitted, the system will fault
MOT relevance

Can It Fail an MOT?

🔍 MOT Implications

An illuminated TPMS warning light is an automatic MOT failure — from May 2018, TPMS was added to the MOT test schedule. Additionally, tyres with insufficient tread depth (below 1.6mm across the central three-quarters of the tyre) or visible damage will cause a separate MOT failure. A faulty TPMS sensor that illuminates the warning light must be repaired or replaced before the MOT.
Repair costs

Typical UK Repair Costs

IssueLikelihoodEst. UK costDIY?
Low Tyre PressureMost Common — 70% of TPMS warningsFree (petrol station air) or £1–£2 (pay-to-use compressor)Yes
Puncture / Slow PunctureCommonTyre puncture repair: £15–£30. Tyre replacement: £60–£300+ depending on tyre and vehiclePro
Faulty TPMS SensorCommon on vehicles over 5 years oldTPMS sensor replacement (per sensor): £40–£100 (parts + fitting). Some vehicles require all four replaced simultaneously for system calibrationPro
TPMS System Calibration RequiredCommon after tyre or wheel changesTPMS calibration: free (self-reset) or £20–£50 at a tyre centre if a programming tool is requiredYes

Costs are estimates based on UK independent garages. Main dealer prices may be higher.

In detail

Common Fixes in Detail

Low Tyre PressureMost Common — 70% of TPMS warnings

Simply inflate the tyre to the recommended pressure. Check all four tyres — the TPMS may only flag the most severely affected. The correct pressure is on the driver's door jamb sticker or in the handbook; front and rear pressures are often different. After inflating, drive for a few minutes — the TPMS light should extinguish automatically on direct systems.

Free (petrol station air) or £1–£2 (pay-to-use compressor)

DIY possible

Puncture / Slow PunctureCommon

A nail, screw, or glass fragment in the tread causes a gradual pressure loss. The tyre appears normal initially but pressure drops over hours or days. A tyre repair shop can plug or patch most tread punctures for a modest cost. Sidewall punctures cannot be safely repaired — tyre replacement is required.

Tyre puncture repair: £15–£30. Tyre replacement: £60–£300+ depending on tyre and vehicle

Professional repair required

Faulty TPMS SensorCommon on vehicles over 5 years old

TPMS sensors contain a battery that lasts 5–10 years. When the battery dies, the sensor fails and the TPMS light illuminates as a system fault (often flashing before remaining solid). The sensor must be replaced — they cannot be recharged. Replacement requires deflating the tyre, removing it from the rim, and fitting the new sensor.

TPMS sensor replacement (per sensor): £40–£100 (parts + fitting). Some vehicles require all four replaced simultaneously for system calibration

Professional repair required

TPMS System Calibration RequiredCommon after tyre or wheel changes

After fitting new tyres, wheels, or sensors, the TPMS system must be recalibrated (relearned). Some vehicles do this automatically after driving above 25mph for several minutes; others require a specific reset procedure using the infotainment menu or a TPMS programming tool.

TPMS calibration: free (self-reset) or £20–£50 at a tyre centre if a programming tool is required

DIY possible

Ownership & maintenance

Ownership & Maintenance

Long-Term Impact

Correctly inflated tyres last significantly longer, improve fuel economy by up to 3%, and provide better wet-road braking performance. Under-inflated tyres wear on the outer edges, overheat during sustained driving, and are at dramatically higher risk of catastrophic failure. UK law requires tyres to be maintained in a roadworthy condition — sustained driving on under-inflated tyres is a legal offence, not just a safety risk.

Good Habits

Check tyre pressures monthly and before any long journey. Use a quality tyre gauge rather than relying solely on the TPMS — the system only alerts at 25% below pressure, which is already dangerous. In autumn as temperatures drop, expect TPMS alerts — check and adjust pressures to account for cold weather pressure reduction.

Recurring Issues

A TPMS light that keeps returning in the same tyre shortly after inflating indicates a slow puncture. Don't repeatedly inflate and ignore it — have the tyre inspected. Similarly, a light that illuminates across multiple tyres simultaneously after cold weather is almost certainly pressure-related rather than a sensor fault.

Vehicle Health

MotR's MOT history data allows you to check whether a vehicle has had previous tyre-related advisories or failures — particularly useful when buying a used car. Repeated tyre advisories in MOT history may indicate a vehicle used heavily with poor tyre maintenance habits.
Questions & answers

Frequently Asked Questions

What does the TPMS warning light look like?
The TPMS light shows a cross-section view of a tyre (U-shaped) with an exclamation mark in the centre, displayed in amber/yellow. On some vehicles it may be labelled "TPMS" or "Tyre Pressure." A flashing version of the same symbol typically indicates a sensor fault rather than low pressure.
Does the TPMS tell me which tyre is low?
Direct TPMS systems (individual sensors in each wheel) can display the pressure of each individual tyre — check your infotainment screen or instrument cluster. Indirect TPMS systems (which use ABS sensors) only indicate that a tyre is low without identifying which one — you'll need to check all four manually.
Will TPMS fail my MOT?
Yes. From May 2018, the TPMS is included in the MOT test. An illuminated TPMS warning light is an automatic failure. The tester will also check that all four sensors are present and functioning. Separately, tyre tread below 1.6mm will also fail the test.
How do I reset the TPMS light after inflating the tyres?
On direct TPMS systems, inflate the tyres to the correct pressure, drive above 25mph for 10+ minutes, and the light should extinguish. Some vehicles have a TPMS reset button in the glovebox or a calibration menu in the infotainment system. Consult your handbook for the specific procedure.
Can cold weather trigger the TPMS light?
Yes, very commonly. Tyre pressure drops approximately 1 PSI for every 5.5°C drop in temperature. A first cold morning in autumn will frequently trigger TPMS lights on cars that were correctly inflated over summer. Inflate to the correct pressure for current conditions.
How much does a TPMS sensor cost to replace?
Individual TPMS sensor replacement typically costs £40–£100 at a tyre centre, including removal from the wheel, fitting, and calibration. Premium vehicles may have higher costs. Some manufacturers recommend replacing all four sensors simultaneously when one fails, to avoid them failing at different times over the following years.
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Warning-light guidance is general UK advice and does not confirm manufacturer-specific behaviour — always check your vehicle handbook. Any illuminated warning light at the time of the MOT test is an automatic failure under the 2018 DVSA rules. MotR is not affiliated with DVLA, DVSA or any vehicle manufacturer. Last reviewed June 2026.

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