Look at eBay and Amazon and you’ll see there are plenty of new and second-hand car keys for sale. The question is, can you programme your car key yourself?

This is the most common question we’re asked, so after answering lots of emails, here’s everything we know.

Programme your car key 101

The first thing you need to know is how the car key works. There are two parts of the key, the first parts is the transponder chip.

programme your car key

Various chips

The chip is important because the car checks it out when the ignition is turned on. It happens in the blink of an eye, and when the car recognises the chip, the car starts. You’ll only notice this happening when you have a car key problem.


Before the car will recognise the chip, it needs to be programmed to the car. This is just a simple introduction, telling the car to accept the chip in future.

Can you programme your car key chip?

The bad news is since 2001, most transponder chips can only be programmed in using a diagnostic computer. The exceptions to this rule are certain Toyota and Lexus cars, early Fords and a few City Rover cars.

I’m not sure you’ll want to admit having a City Rover, let alone need to programme your own car key to one. So we’ll leave it alone

As a general rule, if you buy your own car key from eBay or Amazon, you’ll not be able to programme it to start your car. The programming equipment is expensive and it can be tricky to use. You’ll need to find a local Auto Locksmith, or key cutting shop, or the dealer.

How to find a good Auto Locksmith

So are eBay sellers lying?

No not necessarily. The second part of the key that needs coding is the remote control buttons. In the olden days, most of the time, there was a simple manual method to programme the key.

Watch our  video playlist showing how to programme car keys yourself, your key may be covered.

So if you have a Ford, Toyota, Lexus, Honda, Mazda and early Nissan, then there’s a good chance you’ll be able to programme your car key buttons yourself. This is what eBay sellers are referring to when they suggest you can programme the key they sell.

The problem is the buttons code in easily, but the car still won’t start.

Comments from our YouTube Channel

Here’s a recent comment on our YouTube channel from someone who bought an eBay key.

‘Hi. Thanks for the useful trick to lock and unlock with a spare key. However, when attempting to start the engine with the second key, the red light in the middle of the dashboard blinks quickly leaving me with no other response.

Basically the lock/unlock system is now working for the second key, but the same cannot be said when trying to start the engine. I have this problem on a late-2007 Ford Focus for which I bought a second key.’

Here’s another comment which shows the problems with trying to programme your car key yourself

‘The new fob opens the locks etc remotely using the method in the video but it will not start the car in my case. The ignition lights come on but turn the key to start, and nothing happens. The PATS light flashes. When original remote key fob is used, it works fine.’

This is a common problem we see. Our advice is simple. Before you spend money on eBay or Amazon, contact a local expert, to see if they can code it in. Otherwise you’ll be wasting your money.

We hope this has helped you. Please ask any questions in the comments below.









0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *