McLaren P1 Owner's Handbook Manual page 193

MAINTAINING YOUR McLAREN
MANUAL UNLOCKING AND OPENING
3. Remove the back cover from the key fob
and remove the battery holder.
4. Remove the discharged battery from the
battery holder and install a new battery
ensuring that the polarity is correct.
NOTE: Handle the battery as little as
possible. Moisture and oil from fingers
can affect battery life and cause
corrosion of the contacts. Only hold the
battery on the edges.
5. Fit the battery holder back into the key
fob and replace the back cover.
6. Refit the button pad and the mechanical
key.
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