The Difference Between OEM, Aftermarket and Refurbished Car Keys

Car keys might look simple, but what’s inside them and where they come from makes a big difference to reliability, security and long-term cost. If you’ve ever searched for a replacement online, you’ve probably seen the terms OEM, aftermarket, and refurbished thrown around.

They can sound like small distinctions, but choosing the wrong one can mean a key that doesn’t program properly, fails early, or even compromises your car’s immobiliser. Here’s what those terms really mean, and how to make sure you’re getting the right key for your vehicle.

OEM Car Keys: The Original Standard

OEM (Original Equipment Manufacturer) keys are made by, or for, the same company that supplied your car’s original keys when it left the factory. They carry the exact same transponder chip, housing, and electronics, and are designed to integrate seamlessly with your vehicle’s immobiliser and central locking systems.

They’re considered the gold standard because they offer:

1. Guaranteed compatibility with your vehicle’s software and frequency range.
2. Durable materials: better plastic housings, solid soldering, and factory-level water resistance.
3. Full feature support: keyless entry, remote start, boot release, etc.
4. Reliable programming: less chance of “failed sync” or partial operation.

The downside is price. OEM keys are the most expensive option and often need to be ordered through authorised channels. But for premium or newer vehicles (BMW, Range Rover, Mercedes, etc.), they’re worth it especially since cheaper clones often fail on those brands.

Aftermarket Car Keys: The Copycat Option

Aftermarket car keys are third-party reproductions built to look and function like OEM keys, but manufactured by independent companies. Some are excellent quality; others are cheap imitations.

The advantages:

1. Lower cost typically 30–50% cheaper than OEM.
2. Quick availability most locksmiths stock a wide range of aftermarket blanks and fobs.

However, the risks are real:

• Varying chip compatibility: not all transponder chips can be programmed to all vehicles.
• Weaker materials: thin cases, soft blades and brittle buttons that wear quickly.
• Inconsistent electronics: some remotes lose range, desynchronise, or fail under temperature changes.
• Security concerns: poorly made clones can cause immobiliser or gateway errors during programming.

A reputable auto locksmith will only use tested aftermarket brands that are certified for your vehicle’s system. The problem arises when drivers buy cheap blanks from online marketplaces and bring them to be programmed many of those are counterfeit or poorly built, leading to expensive issues later.

Refurbished Car Keys: Somewhere in Between

Refurbished keys occupy the middle ground. These are genuine OEM keys that were previously used, then reconditioned. A professional refurbisher will replace worn buttons, re-shell the housing, fit a new battery, and reset or replace the transponder chip so it can be safely reprogrammed.

The key point is who did the refurbishing. A properly refurbished OEM key can perform almost as well as new, provided:

1. The PCB and chip are genuine and fully functional.
2. The locksmith uses professional tools to clear previous coding (“unlock” the key).
3. It’s matched to your vehicle’s VIN and tested for full functionality.

Poor-quality refurbs, on the other hand, can carry locked chips, mismatched frequencies, or water damage that only appears later. So while refurbished keys can be an affordable option especially for older vehicles you should always buy them from a licensed locksmith who can verify authenticity.

How to Tell Which One You’re Being Sold

When you contact a locksmith or browse online listings, look out for these signs:

• If the advert says “OEM-style”, it’s usually aftermarket, not genuine OEM.
• A used OEM key might still contain data from the previous car unless it’s been properly reset.
• No brand or part number on the circuit board is a red flag.

Ask for a photo of the PCB (printed circuit board) genuine OEMs often have brand identifiers like Siemens, Valeo, Continental, etc.

A professional provider will specify: “Genuine OEM”, “Certified aftermarket”, or “Refurbished OEM” and issue a 12-month warranty or equivalent.

Which Type Should You Choose?

It depends on your situation:

• For newer cars (2018+): OEM or refurbished OEM are safest for compatibility and reliability.
• For older or second vehicles: certified aftermarket keys can be a cost-effective solution if sourced from a trusted locksmith.
• For leased or company cars: always choose OEM to avoid potential penalties when returning the vehicle.

The most important thing is who programs it. Even a perfect key can fail if it’s coded incorrectly or using unlicensed tools. Always use a specialist who’s authorised and insured to work with your make and model.

Avoid Buying Keys Online Without Expert Advice

It’s tempting to grab a “compatible”  car key from eBay or Amazon, but many are locked, cloned, or counterfeit. In some cases, they can’t even be programmed or worse, they corrupt your immobiliser’s data when an untrained technician attempts to sync them.

A trusted locksmith will check your car’s key frequency, immobiliser system, and the generation of your ECU before choosing the right blank and transponder type. That’s the difference between a key that just “works today” and one that stays reliable for years.

Professional Car Key Replacement and Repair in the UK

If you need a car key replacement or repair, it’s best to contact Phoenix Car Keys a professional UK automotive locksmith service.
Our specialists work exclusively with licensed OEM, certified aftermarket keys, using manufacturer-grade diagnostic and cutting equipment. Every key we supply is tested, programmed and guaranteed to meet OEM-level performance.

We provide a 12-month warranty on all keys we cut and program, so you can drive away knowing your vehicle is fully secure and your key is built to last.

For expert advice, diagnostics or replacement keys get in touch with Phoenix Car Keys today and experience the difference of true automotive expertise.