E90 High Braking Load

[Damien]

I got this high braking load warning and the red engine light on the car today. The car is driving fine but I have it parked up now because I have no idea
what the problem is. Anyone have this problem before or have an idea of what might be wrong. The car is a 2010 e90 petrol engine. Thanks

[Damien]

I got the car scanned today and got the code 5e5d brake fluid level too low so i checked the reservoir and it's full.
Could a faulty sensor cause this problem and is the sensor in the cap on these cars