The TPMS light means at least one tyre is 25% or more below its recommended pressure, OR a tyre pressure sensor has failed. Check all four tyres cold against the door-jamb sticker — a 2-minute top-up clears most cases.
Here's a quick, honest answer from a working UK mechanic — what causes it, what it costs to fix, and what to do next.
Will the TPMS light fail my MOT? — Yes — on cars registered after 1 January 2012, a permanently illuminated TPMS warning is a Major MOT defect and the car will fail. Sort it before the test.
How do I reset the TPMS light after inflating my tyres? — On most cars, drive 5–10 minutes above 20 mph and it resets automatically. On BMW, Mini, Mercedes and some Vauxhalls you need to hold the TPMS reset button (often near the steering wheel) for 3 seconds, or use the dash menu — check the handbook.
Can I drive with the TPMS light on? — Short distances at low speed to reach an air pump, yes. Long motorway journeys, no — if a tyre is significantly underinflated, sidewall flex generates heat and can cause a blowout. Always check the actual pressures before you set off.
Bob's Mechanical Repairs — independent family-run garage in Birnam, Dunkeld, Perthshire. Call 01350 727 276 or email [email protected].