Polo 9n Dash Warning Lights

[MisterC83]

Afternoon Guys,

I've got an 03 Polo 1.4tdi

Every now and then a yellow warning light comes on the dash, usually when its wet out

Its bang in the middle, a yellow circle with 3 little bars either side, what is this warning light?

Thanks in advance

[RUM4MO]

Is that not the brake wear/fluid level indicator, if you look at it again, does it not look like a brake drum and two shoes? - ie two and not three "bars"