Red run flat indicator

[Tomsdad]

Had the red warning light and " chimes" last night. Checked pressures this morning. Front driver side down to 25psi from 33 psi.
Anyone know if that's enough to trigger the warning? Can't see from the handbook what the threshold is.
I am using run flats
I will re inflate all tyres and reset the warning light. Then monitor and see how it goes.

 

[RustyZ4]

I would say that's enough to trigger it, last time mine did that it, one tyre was only down about 3psi!

 

[mmm-five]

Yellow comes on after ±3psi, red comes on after a few more. Don't know the exact figures though.

I got my first one when a front caliper was sticking and heating up the wheel/tyre and caused a 5psi increase.

 

[Crazy Harry]

Yep that's enough. I've had the light come on when one wheel aquaplaned through surface water on the motorway - I think the system (once set whilst the car is in motion) compares the rotational speed of both wheels on the same axle; any difference must mean one is larger than the other; therefore the pressures are different. Of course this is not always the case but pressure diff is most likely.

Or in the case above sticking brakes slow one wheel and create an apparent difference.

No doubt I will be corrected but quite happy to learn a bit more!