1. Disconnect the brake fluid level sensor connector from the master cylinder.
2. 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..

Brake Switch InspectionSae Standards
In accordance with new regulations, SAE (Society of Automotive Engineers)
standard names and abbreviations are now used in this manual. The table below
lists the names and abbreviations that have been used in Mazda manuals up to
now and their SAE equivalents.
...
Clock Spring Inspection [Two Step Deployment Control System]
1. Disconnect the negative battery cable and wait for 1 min or more..
2. Remove the driver?side air bag module..
3. Remove the steering wheel..
4. Remove the column cover..
5. Remove the clock spring..
6. Verify that the continuity is as indicated in the table.
If not as indicated ...
Expansion Valve
Purpose
The expansion valve atomizes liquid refrigerant to facilitate cooling of
the evaporator.
Function
The expansion valve reduces the pressure of liquid refrigerant rapidly to
facilitate vaporization of the atomized refrigerant at the evaporator, and adjusts
the refr ...