A low level of electrolyte fluid will cause the battery to discharge quickly.

Inspect the electrolyte level at least once a week. If it is low, remove the caps and add enough distilled water to bring the level between the upper and lower level (illustration).
Do not overfill.
Examine the specific gravity of the electrolyte with a hydrometer, especially during cold weather. If it is low, recharge the battery.
Battery Maintenance
Battery RechargingMazda 6 Owners Manual: Active Driving Display (Some models)
WARNING
Always adjust the display brightness and position with the vehicle stopped:
Adjusting the display brightness and position while driving the vehicle is dangerous
as doing so could distract your attention from the road ahead and lead to an accident.
CAUTION
Do not try to adjust the ...
Mazda 6 Owners Manual: Crankshaft position (ckp) sensor inspection
Note
Perform the following inspection only when directed.
Resistance Inspection
1. Disconnect the CKP sensor connector.
2. Measure the resistance between CKP sensor terminals A and B using an
ohmmeter.
If not as specified, replace the CKP sensor.
If CKP sensor resistance is okay, bu ...