Take the appropriate action and verify that the warning light turns off.

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Front/rear abs wheel-speed sensor inspection
Visual Inspection
Remove the wheel and tire, and inspect the sensor for looseness and damage.
Replace the sensor if necessary.
Clearance Inspection
Inspect the clearance between the wheel-speed sensor and the sensor rotor.
Clearance
0.3-1.1 mm {0.012-0.043 in}
Resistance Inspection
...
Mazda 6 Owners Manual: i-ELOOP
i-ELOOP is a regenerative braking system. When you depress the brake pedal or
use engine braking, the kinetic energy that occurs is converted to electrical energy
by the power generator and the converted electrical energy is stored in the rechargeable
battery (capacitor and battery). The store ...