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

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Cruise Control Function
While this function is operating, the headway control operation is canceled and
only the cruise control function operates.
The vehicle speed can be set more than about 25 km/h (16 mph).
Use the cruise control function on expressways and other highways which do not
require a lot of repeated acc ...
Mazda 6 Owners Manual: Vehicle speedometer sensor removal/installation
Without ABS
1. Disconnect the negative battery cable.
2. Remove the battery and battery tray.
3. Remove the air cleaner compornent. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
4. Disconnect the vehicle speedometer sensor connector.
5. Remove the vehicle speedometer sensor.
6. Apply transmi ...