On modern Chevrolet key fobs, the key itself is used as a tool to help you swap out the old battery for a new one.

Which is exactly why [Matt Frost] went the non-invasive route. By wiring up an ESP8266 to a cheap aftermarket key fob for his Chevrolet Suburban, he’s now able to wirelessly control the door ...

Criminals are scanning for key fob signals and creating cloned keys, or plugging into a car’s system to program new fobs, ...

For models that don't have this function, an intermittently working key fob is a good indicator. Changing the battery on an Audi key fob is a fairly simple operation, and an Audi dealer can do it ...

where thieves use electronic devices to replicate key fobs and steal cars. Criminals are exploiting keyless ignition technology by scanning for key fob signals and creating cloned keys ...