Volvo XC90 Owner's Manual page 95

Locks and alarm
Keys and remote controls
Changing the remote control
battery
If the locks repeatedly fail to react to signals
from the remote control at a normal distance,
the battery should be replaced.
– Remove the cover by carefully prising up
the rear edge of with a small screwdriver.
– Replace the battery (type CR 2032, 3 V)
– with the plus side facing up. Avoid
touching the battery and its contact
surfaces with your fingers.
– Refit the cover. Make sure the rubber seal
is properly fitted and free from damage to
prevent water from entering.
VQ
– Turn the old battery in to your Volvo
workshop so that it is disposed of in an
environmentally friendly way.