It could be the Tire Pressure Monitor (TPM). These can be usually be found on the inside of each wheel.
It indeed means there's something wrong with your tire pressure.It can mean that one of your tire or all of them have lost pressure, so check your tires pressure.For the M3, the sticker with the correct tire pressure is glued to driver's door sill near the door latch.It can also be on because you changed your tire pressure, either you or the mechanic that works on your car.If that's the case it needs to be reset.There are many ways to do that depending on the model.If I remember correctly on 3-series you can do it with the indicator stalk on the steering column.There should be a button written BC on it and a small toggle just beside it.Use the toggle to move through the menu on the little screen in the instrument cluster.Once you have the tire pressure marker icon, press on the BC button and hold it until a little box with a mark in it and the word RESET appears. If that fails then go see your dealer he will be able to make it go away
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