The blade operates a physical lock
A mechanical blade is cut to suit a lock. On some vehicles it is the everyday ignition key; on others it is an emergency key stored inside a remote. The presence of a blade does not establish that it can start the engine on its own.
Check the relevant locks in your owner’s manual. A blade supplied for emergency door access should not be assumed to provide every function of the complete electronic key. This matters when comparing a quote for a cut blade with a quote for a full replacement.
A transponder key supplies electronic identification
A transponder, often called a chip, can form part of the vehicle’s starting authorization. Ford’s SecuriLock description, for example, says its coded ignition key must be programmed to the vehicle before the engine can start. That example explains why a blade that fits is not necessarily a complete starting key.
The exact system depends on the vehicle. Ask whether your replacement needs cutting, electronic programming or both. Do not assume that a mechanical copy has received whatever electronic work the car requires.
A remote fob controls remote functions
People often use “fob” for any key housing with buttons. The useful details are which buttons operate the doors or trunk, whether the key goes into an ignition, and whether you start the vehicle with a button. A familiar-looking case does not settle compatibility.
Remote unlocking and starting should be described separately when reporting a fault. Tell the provider if the car unlocks but does not recognize the key for starting, or starts normally while the remote buttons do nothing. Those observations narrow the request without guessing the failed part.
A smart key may combine several jobs
A smart-key system can support keyless access and starting, with the particular features depending on the vehicle. Some remotes also hold a mechanical backup blade. Honda’s Accord Hybrid key documentation describes that built-in key as a way to unlock a door when the remote’s normal operation is unavailable.
Use the instructions for your own year and model when a key battery is weak or the vehicle reports a key problem. Procedures for another car are not a reliable substitute, even if the two fobs look similar.
Request the functions you need
For a replacement or spare, give the year, make and model and state whether another key still works. Tell the provider whether you need door access, engine starting and remote functions. If you already bought a part, supply its product details for checking before a visit.