Re: Low brake fluid?
I have had this on a number of cars, including my 159.
In the brake fluid reservoir under the bonnet is a float, which, if it drops too low, activates a warning switch. Basically, on a long fast bend the fluid in the brake fluid reservoir under the bonnet moves to one side, and the float drops accordingly, activating the warning switch.
You should check the reservoir on the flat, to see if it is within the min/max levels. You might consider topping it up to max if you want, which may stop this message appearing.