What does it mean when the tyre pressure light flashes and then stays on?

It means the monitoring system has a fault and can no longer tell you anything about your tyre pressures. It is not telling you a tyre is soft. Cars signal the two conditions differently on purpose: a steady lamp from the moment you start means low pressure, while roughly a minute of flashing followed by a steady lamp means the system itself has failed — usually a sensor that has stopped transmitting, most often because its sealed battery has run out. The MOT inspection manual describes this behaviour in the same terms, which is how a tester distinguishes a car that should fail from one that just needs air.

Will a TPMS fault fail an MOT?

Yes, on cars first used on or after 1 January 2012. A tyre pressure monitoring system that is malfunctioning or obviously not working is a major defect under section 5.2.3 of the inspection manual, and across the DVSA data behind this site it accounts for 97,515 failures — the second largest warning-lamp defect of any kind. What will not fail the car is a lamp lit because a tyre genuinely needs air; an obviously under-inflated tyre is only a minor defect. Where a tester cannot tell which they are looking at, the manual tells them to add advisory information rather than reject the car.

Can I just have the TPMS system switched off?

Not if you want the car to pass its MOT. On a vehicle first used on or after 1 January 2012 the system was part of its type approval, and a system that has been disabled is by definition obviously inoperative, which is a major defect. A reputable garage will not do it for that reason. It is also worth knowing that some cars will simply keep the warning lamp lit anyway, so you end up with the failure and the lamp. Replacing dead sensors is a routine job usually done while the tyre is off the rim, and is far cheaper than most people expect.

Do I need TPMS sensors in my winter wheels?

On a car first used on or after 1 January 2012, effectively yes. Fitting a second set of wheels without sensors leaves the system unable to hear from any corner, so it reports a malfunction — which is the state that fails an MOT if the car is tested on those wheels. The usual approach is a matching set of sensors in the winter wheels, learned to the car when you swap over; many cars can store two sets and recognise which is fitted, while others need a short relearn procedure each time. Some sensors are programmable, so a tyre specialist can clone the identities across rather than supplying new ones.

Dashboard warning light

Tyre pressure monitoring system fault light

Last updated 27 July 2026

Quick answer

The monitoring system itself has failed, rather than a tyre being soft. On most cars it uses the same symbol as the ordinary tyre pressure warning but announces itself differently: it flashes for around a minute after you switch on and then stays on steadily. That behaviour is the single most useful thing to know here, because it is also exactly what the MOT tester looks for.

What to do: Get it checked within days
Can you drive?: Yes

Why it is amber

A system has reported a malfunction, or something needs attention. The car is usually still driveable, but the fault will not clear itself and several amber lamps are an automatic MOT failure.

What turns it on

The car checks that it can hear from every wheel sensor and that the system is calibrated. If a sensor stops transmitting, has never been learned to the car, or the receiver cannot make sense of the data, the system cannot monitor pressures and says so. The flash-then-steady sequence is the standardised way of signalling that: it distinguishes a system that has stopped working from a system that is working and reporting a low tyre.

What to do about it

Watch the lamp at start-up. A brief flicker as part of the bulb check is normal. Roughly a minute of flashing followed by a steady lamp is the fault signal, and no amount of air will clear it.
Think about what changed. New tyres, a wheel swap, winter wheels, a puncture repair or a battery disconnection immediately before the lamp appeared points at sensors that need relearning to the car rather than replacing.
Have it scanned. A TPMS tool will say which corner is not reporting and whether the sensor is dead, missing or simply unlearned, which is the difference between a menu procedure and a new sensor fitted into the tyre.
If the car is coming up for its MOT, deal with it first. This is the version of the lamp that fails the test, and it is a straightforward fail rather than an advisory.
Check whether the sensors are simply old. Direct sensors have a sealed, non-replaceable battery that typically lasts somewhere around seven to ten years, after which they die one by one, and a car of that age will usually need the set.
Do not have the system disabled to make the lamp go away. On a car first used on or after 1 January 2012 that is an MOT failure by definition, because the system is then obviously inoperative.

Can you keep driving?

Yes

The car drives entirely normally — what you have lost is the monitoring, not any part of the tyre or the braking. The catch is that you are now back to checking pressures yourself, and the whole reason the system was made mandatory is that most people do not. Get into the habit of a monthly gauge check until it is fixed, and remember that this is the version of the lamp that fails an MOT.

What causes it

A flat sensor battery, which is the usual outcome on any car past about seven years old and cannot be replaced separately from the sensor
Sensors not relearned to the car after new tyres, a wheel rotation or a wheel swap
Aftermarket or second-hand wheels fitted without sensors at all
A winter or summer wheel set with its own sensors that the car has never been taught
A sensor physically damaged during tyre fitting, which is easily done because it is part of the valve
Corrosion snapping an aluminium valve stem, killing the sensor with it
A faulty receiver module or an aerial connection, which on some cars also affects the remote locking
Radio interference from an aftermarket accessory near the receiver

Does it fail an MOT?

Not on its own — but what causes it often does.

This is the lamp behind the MOT failure, but the reason for rejection is recorded on the tyre pressure warning light page so the national figures are not counted twice. In short: under section 5.2.3 a tyre pressure monitoring system that is malfunctioning or obviously not working is a major defect on cars first used on or after 1 January 2012. The manual describes exactly this lamp behaviour, noting that in the event of a system malfunction the lamp may flash a number of times and then remain on, and it instructs testers to reject the car only where it is clear the lamp indicates a malfunction rather than a low tyre — adding advisory information instead where that is unclear. An obviously under-inflated tyre, by contrast, is only a minor defect.

Fault codes that turn this light on

The lamp tells you which system reported a problem. The code stored behind it names the check that failed, which is the difference between knowing something is wrong and knowing where to look. These are the ones that commonly sit behind this symbol.

C0960 Tyre pressure monitoring module has failed
C0910TPMS Receiver Circuit Malfunction
C0950 Front left tyre pressure sensor not reporting
C0900TPMS Sensor 1 Battery
U0140 No communication with the body control module

Got a different code? Look it up — the index covers every standard OBD-II code.

Common questions

What does it mean when the tyre pressure light flashes and then stays on?: It means the monitoring system has a fault and can no longer tell you anything about your tyre pressures. It is not telling you a tyre is soft. Cars signal the two conditions differently on purpose: a steady lamp from the moment you start means low pressure, while roughly a minute of flashing followed by a steady lamp means the system itself has failed — usually a sensor that has stopped transmitting, most often because its sealed battery has run out. The MOT inspection manual describes this behaviour in the same terms, which is how a tester distinguishes a car that should fail from one that just needs air.
Will a TPMS fault fail an MOT?: Yes, on cars first used on or after 1 January 2012. A tyre pressure monitoring system that is malfunctioning or obviously not working is a major defect under section 5.2.3 of the inspection manual, and across the DVSA data behind this site it accounts for 97,515 failures — the second largest warning-lamp defect of any kind. What will not fail the car is a lamp lit because a tyre genuinely needs air; an obviously under-inflated tyre is only a minor defect. Where a tester cannot tell which they are looking at, the manual tells them to add advisory information rather than reject the car.
Can I just have the TPMS system switched off?: Not if you want the car to pass its MOT. On a vehicle first used on or after 1 January 2012 the system was part of its type approval, and a system that has been disabled is by definition obviously inoperative, which is a major defect. A reputable garage will not do it for that reason. It is also worth knowing that some cars will simply keep the warning lamp lit anyway, so you end up with the failure and the lamp. Replacing dead sensors is a routine job usually done while the tyre is off the rim, and is far cheaper than most people expect.
Do I need TPMS sensors in my winter wheels?: On a car first used on or after 1 January 2012, effectively yes. Fitting a second set of wheels without sensors leaves the system unable to hear from any corner, so it reports a malfunction — which is the state that fails an MOT if the car is tested on those wheels. The usual approach is a matching set of sensors in the winter wheels, learned to the car when you swap over; many cars can store two sets and recognise which is fitted, while others need a short relearn procedure each time. Some sensors are programmable, so a tyre specialist can clone the identities across rather than supplying new ones.

This is general guidance, not a diagnosis. Manufacturers draw the same system differently and reuse symbols for more than one function, so check the handbook for your own car before acting on anything here.

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