On my 2004 TD6, I have the red brake warning light on, so I plugged my diagnostics in as the car had brand new pads 3 weeks ago and 1 new wear sensor. It comes up with brake fluid low. So I checked the brake fluid level. It is on the maximum.

Could weak brake fluid cause the same fault message to occur?

I think the brake fluid sensor works on a float sensor in the top of the resovoir. Coud be an issue with the cable on the sensor. Can you test the feed to it. The system isnt sophisticated enough to measure weak fluid unless im totally wrong! Current 2007 TDV8 Vogue Buckingham Blue

Take the reservoir cap off & turn it upside down, so the float contacts the cap.
If the warning light doesn't turn off - either the cap contacts or wiring to it have a fault.
If it does turn off, maybe the float is sticking or faulty (eg is full of brake fluid)

PS it definitely isn't clever enough to know anything useful about the fluid - lol. Paul,
2001 Discovery 2 TD5, 211,000 miles & climbing
2006 FFRR TDV8 Vogue 145,000 miles & climbing
Member of Midland (Land) Rover Owners Club, www.mroc.co.uk