Run flat tyres warning light!

[gingerninja32]

The run flat tyre warning light has just come up on my dash on my E46 M3, I have looked at the manual, it just says to get it checked out. Anybody had this problem before or wud have an idea of what the problem might be? Easily fixable etc! Im going to get it checked tomorrow, just want to have a bit of an idea what im talking about!

Cheers!

[greygoose]

Have you checked the tyre pressures?

[gingerninja32]

No not yet, going to go check in the morning! Would that be enough to trigger the run flat warning light?

[Crusoe]

Should check your tyre pressure every week, makes a big difference to the way the car feels on the road when it is right. Red run flat warning a few hundred yards into a journey is the warning that your tyre is flat, tend to go off between 5 and 10psi below where they were reset at depending on how fast you drive. Once you find the low one pump it up then check the pressures are correct all round. Reset the warning with the ignition turned half and the button depressed for the tyre warning in front of the gear leaver. The light then goes orange if I remember correctly which is it resetting the new levels and then it will warn with the red again if you drop below that.

[andye30m3]

My warning light come on occasionally (almost always at the same corner on the way to work) and there's never been anything wrong with the pressures,

From what I've heard most of these systems can be a bit temperamental at times.

[Big E 118]

The light can be triggered by wheelspin/slip, check your pressures and if OK do the reset. If the light comes back on again fairly soon you could have a slow puncture.

[Gruber]

Big E 118 said:

The light can be triggered by wheelspin/slip, check your pressures and if OK do the reset.

Indeed. The "pressure sensors" don't actually monitor pressure, as I understand it. They essentially work on counting wheel revolutions - if the rolling circumference drops then the system assumes a puncture and the light comes on.

[clived]

gingerninja32 said:

Would that be enough to trigger the run flat warning light?

It isn't a run flat warning light. It's a tyre pressure warning light (although as has been said it isn't measuring pressure, but using wheel rotational speed vs the othre wheels as a proxy for it). So yes, the pressure in a tyre being down will indeed trigger the tyre pressure warning light ;-)

[toasty]

All 3 of the BMWs I've had have had the tyre pressure warning light come on at some point or another.

Once it was even correct, I had a nail in the tyre.

Check the pressures and reset if they're all OK. Most of the time they will be.

FWIW BMW don't put run flat tyres on M Cars.

[gingerninja32]

Right i went and checked the pressures, and they were a little off! Did the reset and it was fine for a few miles then came back on again. Ive done that three times now and it still comes back on. Anybody think of anything else to try before I bite the bullet and go to the garage and ask them to have a look?

[andye30m3]

If it's coming on that often and the pressures are fine, I'd get someone to plug it into a diagnostics machine.

I think the system takes it's readings from the same wheel speed sensors that the ABS uses so it maybe one of the sensors id on it's way out. (I maybe corrected on this)

[blondini]

gingerninja32 said:

Right i went and checked the pressures, and they were a little off! Did the reset and it was fine for a few miles then came back on again. Ive done that three times now and it still comes back on. Anybody think of anything else to try before I bite the bullet and go to the garage and ask them to have a look?

You just need to re-initialise the system.

Having reset the red warning lamp first by holding down the button until it goes out, switch off ignition and switch on again.
Now hold down the button again until the warning lamp comes on orange, start the car and drive off. The lamp will go out in a short distance and it shouldn't come back on unless there is a puncture.

[gingerninja32]

Sorted, thanks for all the help!

[ash2406]

gingerninja32 said:

Sorted, thanks for all the help!

Hi gingerninja32,

Sorry to bother you, I know its very old post.
I am facing exactly the same issue in my 320D. Low pressure warning came 3rd time this morning in last couple of weeks. Please share how you resolved this issue? Did you go to any mechanic ?

Regards,
Ash

[mikeN54]

It means you have low pressure in a tire.

Check your pressures, you might find a flat tire. If they seem okish then pump up as required and reset the TPMS (tyre pressure monitoring system).

See how it goes.

[ash2406]

mikeN54 said:

It means you have low pressure in a tire.

Check your pressures, you might find a flat tire. If they seem okish then pump up as required and reset the TPMS (tyre pressure monitoring system).

See how it goes.

Thanks, I did this last evening. I'll update the result if this bounces back sooner than expected.

Regards,
Ash

[jpeters26]

Hi there,

I have a 2007 mini cooper with run flats. I had the alignment done and two new tyres fitted last week but the garage cannot work out how to turn my red run flat light off on the dash. My computer/navigation system is broken so I cannot use that to reset it. I have looked at videos online of how to reset the light and they all say to press the BC button until you get to reset but there is no reset on my dash. It just goes from check info to setting the time and date.

Can anyone help?! The garage said I won't pass my next MOT if the light is still on!

[E30M3SE]

If your car has iDrive and that is not working you can't reset the run flat light using any of the cars reset functions or controls, but as your car is a 2007 model it will not fail the next MOT if it is on, this fail only applies to cars registered after 1st January 2012. HTH.

[Smuler]

E30M3SE said:

If your car has iDrive and that is not working you can't reset the run flat light using any of the cars reset functions or controls, but as your car is a 2007 model it will not fail the next MOT if it is on, this fail only applies to cars registered after 1st January 2012. HTH.

Out of curiosity , do you know why this exemption is for runflats.
My 2004 M3 failed (in 2017) for TPMS warning lamp indicates a fault 4.1.D.4
I thought it was same thing ?

[E30M3SE]

Smuler said:

Out of curiosity , do you know why this exemption is for runflats.
My 2004 M3 failed (in 2017) for TPMS warning lamp indicates a fault 4.1.D.4
I thought it was same thing ?

The type of tyre makes no difference a 2004 car with TPMS warning on dash should not have failed its MOT test.