Battery Replacement Made Simple

Battery Replacement Made Simple

When your dash flashes “NO KEY FOUND” or “KEY IN SLEEP MODE”, the car isn’t seeing the fob reliably. Don’t panic—GM built a close-range backup start right into the Corvette so you can get moving first, then swap the coin cell in minutes.

What’s going on (quick take)

The remote key’s battery is weak or dead. You may also see “REPLACE BATTERY IN KEY.” Less commonly, nearby electronics or metal objects can interfere with the signal. The fix is two-part: start the car using the built-in backup, then replace the coin cell.

Get rolling now (backup start)

  1. Place the fob in the cupholder with the mechanical-key end up.
  2. Shift is in P (or N).
  3. Press the brake, then press ENGINE START/STOP.
    If the battery is merely weak or asleep, the car will read the transponder at close range and start normally.

Why this works

There’s a remote key pocket/RFID receiver beneath the cupholder that can read the key’s chip at very short range even when the fob battery is low.

After you start: replace the coin cell (do this ASAP)

Battery type: CR2450 coin cell (negative side faces down).

Fast steps

  1. Press the side button and pull out the mechanical key.
  2. Use the key blade in the slot to pop the cover by hand.
  3. Pull the small tab to lift the seal, remove the old cell ( no metal tools).).
  4. Drop in the new CR2450 with the negative side down.
  5. Press the seal back into its groove, snap the cover on, and reinsert the key.

Safety notes

  • Keep coin cells away from children; if swallowed, seek medical help immediately.
  • Avoid touching internal circuitry (static can damage it).
  • Use only the correct type; dispose of the old cell properly—do not crush, cut, or incinerate.
  • Ensure the seal is fully seated to keep moisture out.

Pro tips that save time

  • If you see “KEY IN SLEEP MODE,” nudge or rotate the fob and try again.
  • Keep phones, power banks, and metal items away from the fob while starting.
  • Unplug USB/12-V chargers during start if you suspect interference.
  • Stash a spare CR2450 in the glovebox so you’re never stuck.
  • After replacement, test both lock/unlock and a normal push-to-start outside the cupholder.

Ready to button this up?

Swap your fob battery today and keep a spare in the car. For a tidy, one-and-done solution, pick up an ACS Composite coin-cell service kit and browse their C8 tech resources/installation guides for more quick Corvette maintenance wins.

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