Brake fluid level switch

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2016 MINI Cooper Countryman, 2015 MINI Cooper Countryman, 2014 MINI Cooper Countryman, 2013 MINI Cooper, and 2012 MINI Cooper. However, it is still accessible from the selected car via links, so may be relevant.

A low brake fluid level is picked up (in the expansion tank via a reed contact) and notified to the DSC control unit. If the brake fluid level is too low, the DSC is deactivated. Otherwise, there is a danger that air will be drawn into the brake system.

Fig 1: Identifying Brake Fluid Expansion Tank, Brake Fluid Level Switch And Two-Pin Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.

Item	Explanation
1	Brake fluid expansion tank
2	Brake fluid level switch
3	two-pin plug connection

The brake fluid level switch detects low fluid levels in the brake fluid reservoir. The DSC control unit sends the signal of the bus system to the instrument panel. The instrument panel issues a Check Control message. The usual motion of the brake fluid within the reservoir does not generally trigger a Check Control message. There is a reed contact inserted in the side of the brake fluid expansion tank. The reed contact transmits an electrical signal if the brake fluid level falls below a specified minimum level. The reed contact is closed while the brake fluid level is above the minimum mark.