Brake Fluid Level Sensor Inspection

WARNING: This page is about a different car, the 2007 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect the brake fluid level sensor connector from the master cylinder.
Inspect for continuity according to fluid level between the brake fluid level sensor terminals.
- If not as indicated in the table, replace the reserve tank.
  
  Fig 1: Checking Brake Fluid Level Sensor Continuity
  Courtesy of MAZDA MOTORS CORP.
  
  Fig 2: Identifying Brake Fluid Level Sensor Connector Terminals
  Courtesy of MAZDA MOTORS CORP.