TPMS Warning Light: What It Means and What to Do

What the TPMS light actually means

TPMS stands for Tyre Pressure Monitoring System. UK and EU law has required it on every new passenger car sold since November 2014. The familiar amber symbol — an open horseshoe with an exclamation mark inside — comes on when one or more tyres are at least 25% below the recommended pressure, or when the system itself has a fault.

Two warning behaviours matter:

• Solid amber — at least one tyre is under-inflated. Reduce speed, check pressures soon.
• Flashing for ~60 seconds, then solid — the TPMS system itself has a fault (failed sensor, dead sensor battery, missing wheel). The system can't monitor pressure until fixed.

TPMS warning light on: is it safe to keep driving?

Short answer: get to a safe stop, then check. A 25% under-inflated tyre runs hotter, flexes more in the sidewall, increases stopping distance and burns more fuel. At motorway speed it can fail catastrophically within 50–100 miles.

If the tyre looks visibly flat or you can hear hissing — stop. Don't try to "make it home". Call a mobile fitter or recovery. If the tyre still looks normal, drive at moderate speed to the nearest petrol station and check all four pressures.

Common reasons the light comes on

1. Cold weather. Tyre pressure drops about 1 PSI for every 10°C fall. A car parked overnight in November can lose 3–4 PSI by morning — enough to trip TPMS without any leak.
2. Slow puncture. A small nail or screw causes a gradual drop over hours or days. Often the tyre still looks round but is 6–10 PSI low.
3. Dead sensor battery. Direct TPMS sensors have a sealed battery that lasts 5–10 years. After that, the sensor goes silent and the system flags a fault.
4. Sensor knocked off during a tyre change. A careless tyre bay can damage the sensor stem when breaking the bead.
5. Wrong winter wheels. Switched to a second set of alloys without TPMS sensors? Light will be on permanently until sensors are fitted and programmed.
6. Aftermarket sealant. Tyre sealant from emergency kits can clog the sensor port. Tell your fitter — most can clean and re-seat it.

How to reset the TPMS warning light

First, fix the underlying cause — inflate to the correct pressure or replace the faulty tyre/sensor. Reset method depends on which system you have:

• Indirect TPMS (uses ABS sensors — most VW, Renault, Vauxhall pre-2018): drive 10–20 minutes above 25 mph, or press the TPMS reset button on the dash / in the menu.
• Direct TPMS (sensor inside each wheel — BMW, Mercedes, Audi, most premium): many relearn automatically within 10 minutes of driving. Others need a menu reset (BMW iDrive → Vehicle → Tyre Pressure → Reset) or an OBD/TPMS programming tool.

If the light returns within a day, you almost certainly have a slow puncture or a failing sensor — not a "false alarm".

Correct tyre pressures — where to find them

Don't guess. Manufacturer pressures are printed on a sticker in one of these spots:

• Driver's door jamb (most common)
• Inside of the fuel filler flap
• Glovebox lid
• Owner's handbook

Check cold — first thing in the morning, before driving more than a mile. Pressures rise 3–5 PSI when tyres are warm.

TPMS sensor cost in the UK (2026)

• Universal programmable sensor: £25–£45 each
• OEM sensor (BMW, Audi, Mercedes, Tesla): £55–£110 each
• Programming and fitting: £15–£25 per wheel
• Full set of 4 fitted and programmed: typically £160–£360

When to call a mobile fitter

Call rather than drive if:

• A tyre is visibly flat or losing air faster than you can inflate it.
• The TPMS light came on with a bang, vibration or steering pull.
• You're on a motorway hard shoulder — never attempt repairs in a live lane.
• You've added air twice in 48 hours and it keeps going down.

Book a mobile tyre fitter — most jobs across London and major UK cities are completed in 35–60 minutes, including TPMS reset on the way out.

TPMS warning light FAQs

Related reading

• Flat tyre in London: emergency steps & mobile fitter guide
• Run-flat tyres UK: how they work, costs & when to replace