change key battery MAZDA MODEL CX-3 2017 Owner's Manual - RHD (UK, Australia) (in English)

3–4
Before Driving
Keys
CAUTION
Changes or modi¿ cations not expressly
approved by the party responsible
for compliance could void the user's
authority to operate the equipment.
NOTE
  The keyless entry system operation
may vary due to local conditions.
  The keyless entry system is fully
operational (door/liftgate lock/
unlock) when the ignition is switched
off. The system does not operate
if the ignition is switched to any
position other than off.
  If the key does not operate when
pressing a button or the operational
range becomes too small, the
battery may be weak. To install a
new battery, refer to Key Battery
Replacement (page 6-37 ).

 Battery life is about one year.
Replace the battery with a new one
if the KEY indicator light (green)
À ashes in the instrument cluster.
Replacing the battery about once
a year is recommended because
the KEY warning light/indicator
light may not illuminate or À ash
depending on the rate of battery
depletion.
  Additional keys can be obtained at
an Authorised Mazda Repairer. Up to
6 keys can be used with the keyless
functions per vehicle. Bring all keys
to an Authorised Mazda Repairer
when additional keys are required.