Why is my tyre pressure warning light on?

The TPMS (tyre pressure monitoring system) warning light means one or more tyres are significantly under-inflated, or a sensor has failed. Check your tyre pressures at a petrol station immediately — under-inflated tyres affect handling and fuel economy, and can cause a blowout at speed. If pressures are all correct and the light stays on, a TPMS sensor may have failed.

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Likely causes

Likely

Under-inflated tyre(s)

Check all four tyres at a petrol station — including the spare if fitted with a sensor

Likely

Slow puncture

A nail or screw causing gradual pressure loss

Possible

Faulty TPMS sensor

Sensors have a battery life of 5–10 years — older cars are more prone to sensor failure

Possible

Recent tyre change without sensor reset

Sensors need recalibrating after a tyre change

Repairs you may need

Typical cost range: £5–£180Inflating tyres costs nothing. Puncture repair £10–30. TPMS sensor replacement £50–180 per sensor.

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Related questions

This information is a general guide based on common causes of this symptom. Symptoms can have multiple causes and accurate diagnosis requires physical inspection by a qualified mechanic. Always consult a professional before deciding not to repair.