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: Oil filter
OIL FILTER REPLACEMENT
For Europe (LF and L3 engine models)
Caution
To avoid damage to the oil filter, use only specified oil filter.
1. Remove the oil filter drain plug.
2. Untighten the oil filter cover for 2 turns and drain the engine oil.
Note
Oil could be easily drained when th ...
Mazda 6 Owners Manual: Theft-deterrent control module inspection
1. Remove the theft-deterrent control module without disconnecting the
connectors.
2. Measure the voltage at the theft-deterrent control module terminals as
indicated below.
3. Disconnect the theft-deterrent control module connector before inspecting
for continuity at terminals L, Q, S, T, a ...