A low-battery warning does not provide a reliable countdown. How long a fob continues to work varies by vehicle, fob, battery condition, and use. Replace the battery promptly with the exact type specified in your owner’s manual or marked on the old battery. For help, see how to change a key fob battery.
What should I do if the key fob stops working?
Use your vehicle’s owner’s manual for its emergency door-entry and backup-start procedure. These steps vary by model. A key-fob battery problem does not by itself mean the vehicle’s 12-volt battery needs a jump-start.
If your vehicle supports a spare programmed fob, keep it available and follow the owner’s manual for using it.
How long can a key fob keep working after a low-battery warning?
There is no dependable universal countdown. Remaining operation varies by vehicle, remote, battery condition, and use, so replace the cell promptly instead of planning around a number of days or months. If the fob stops working, use the emergency-entry and backup-start procedure in that vehicle’s owner’s manual; those steps are model-specific. A spare fob can help if you have one.
Sources: Buick Keyless Open and Start Guidance; Romeo Chevrolet: Key Fob Battery Replacement
