Tempted to save money by DIYing a new key fob or smart key for your car? It could save you hundreds.

Key fobs are a generally pretty mundane and overlooked piece of automotive paraphernalia. A few decades ago, drivers didn't have a way to remotely unlock their cars, and now it's taken for granted.

Some car key fobs have many features built in that owners may not even be aware of. Here's our expert guide to hidden key fob features.