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Key fob battery — warm it up in cold weather before replacing

Key fob

Key fob battery weak on a freezing morning? Coin cells lose power in the cold. Warm the key fob in a pocket and retest before buying a new battery.

Illustration of a generic car key fob and coin cell battery in falling snow
Photo: CoraCo Studio™ original (generated)

A key fob battery can seem dead on a frosty morning and then work fine an hour later. Coin cells give less power when they are cold, so warm the fob first and test again.

Warm a cold key fob battery before you replace it

  1. Hold the key fob in an inside pocket or your closed hand for five to ten minutes.
  2. Stand near the car and press lock once. Check whether range is back to normal.
  3. If it works warm but fails every cold morning, the coin cell is near its end. Plan a new battery soon.
  4. Keep the spare fob indoors, not in a cold car or garage.

If the fob stays weak when warm, test the battery or swap it.

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