Tyre Pressure Warning Light (TPMS)

Can I keep driving?

What to do right now

1. 1Grip the steering wheel firmly, reduce your speed gently, and avoid harsh braking or sudden turns.
2. 2Pull into a safe car park or petrol station forecourt as soon as possible.
3. 3Walk around the vehicle to check whether any tyre looks visibly deflated or flat.
4. 4Do not drive on a completely flat tyre; fit your spare wheel or call for roadside assistance.

Likely causes

Most likely first.

1. Likely

   Slow puncture from road debris

   A small nail or screw lodged in the tread allows air to escape gradually over several days. The monitoring system triggers the light once pressure drops below the safe threshold.

2. Likely

   Cold weather temperature drop

   Air contracts as the outside temperature drops overnight, reducing tyre pressure by roughly one to two psi for every ten degrees Celsius. This natural contraction often sets off the light on cold mornings.

3. Possible

   Depleted TPMS sensor battery

   Wheel-mounted sensors rely on small internal lithium batteries that last roughly five to ten years. When a battery dies, the sensor stops transmitting and causes the dashboard light to flash on startup.

4. Possible

   Leaking valve core or damaged rim seal

   Corrosion around the aluminium wheel rim or a perished rubber valve stem allows air to seep past the tyre bead. This gradual loss triggers the pressure warning without any puncture in the tread.

5. Possible

   Uncalibrated system after tyre service

   Rotating wheels, replacing tyres, or topping up pressures without resetting the system confuses the onboard computer. The system expects old baseline values and flags an error.

What you can check yourself

Park somewhere safe and level, engine off, before you start.

1. 1

   Visual tyre walkaround

   Park on level ground with the engine switched off and the handbrake engaged. Inspect all four tyres to confirm none are sitting on the rim, bulging at the sidewall, or completely flat.

2. 2

   Check tyre pressures with a gauge

   Use a digital or forecourt pressure gauge while the tyres are cold. Compare the reading against the recommended pressures printed on the sticker inside your driver's door pillar or inside the fuel flap.

3. 3

   Search tread for foreign objects

   Turn the steering wheel fully to one side so you can view the front tyre tread clearly. Run your eyes along the grooves for embedded screws, stones, or sharp metal, taking care not to cut your hands.

4. 4

   Reset the monitoring system

   Once all tyres match the handbook specifications, find the TPMS reset button or calibration option in your dashboard menu. Drive for five to ten minutes to allow the computer to store the new pressures.

Typical prices in Ireland (€) and the UK (£), from an independent garage up to a main dealer. Costs depend primarily on whether a tyre can be safely patched or must be replaced, and whether a faulty pressure sensor requires electronic pairing to the car.

When to go to a garage

• A tyre drops pressure again within hours or days after inflating it.
• There is visible sidewall damage, blistering, or an embedded screw close to the edge of the tread where repairs are illegal.
• The warning light flashes for about sixty seconds every time you start the car and remains on, pointing to an electronic fault.
• The dashboard warning refuses to clear even after setting all pressures correctly and completing the manual reset procedure.

Questions drivers ask

Test rules here are for the National Car Test in Ireland (NCT) and the MOT in the UK. Elsewhere, check the regulations of your own country or state before going for a vehicle test.