Hello, 

I have a normal spare key for my 2009 MK7 fiesta and thinking of upgrading it. 

The spare key has a transponder inside so I am thinking of getting a circuit board and key assembly from aliexpress and just reuse the transponder? 
 

Do you think the circuit board will work to open and close the car with my old transponder? 
 

thank you! 

Has your spare key got a flip out blade, or does the replacement come with one that would need cut?

As far as I know, the transponder communicates with the immobiliser passively allowing you to start the car, rather than sending the signal to lock/unlock.  I could be wrong though.

Prise it open and see what's inside.  If you can use it to remotely unlock and lock, it will have a circuit board and battery inside.

Well the idea is fine, I'm just not sure how easy it is to get the transponder chip out of your original key. From the photo it does look like you might be able to gently leaver it out.

As far as knowing if that particular keyfob will work with your car it's difficult to say without knowing what your normal remote keyfob looks like. Of course you will need to programme it in to the car using Forscan as I think the old system of being able to code them in to the car using the ignition turns may not work on your model.

 

5 minutes ago, mickywrx said:

Has your spare key got a flip out blade, or does the replacement come with one that would need cut?

As far as I know, the transponder communicates with the immobiliser passively allowing you to start the car, rather than sending the signal to lock/unlock.  I could be wrong though.

Prise it open and see what's inside.  If you can use it to remotely unlock and lock, it will have a circuit board and battery inside.

The spare key doesn’t have a flip out blade but the new one I am buying comes with it. 

I will have a look to see if I can get the transponder out 🙂

5 minutes ago, mickywrx said:

As far as I know, the transponder communicates with the immobiliser passively allowing you to start the car, rather than sending the signal to lock/unlock

You are correct. The keyfob contains two seperate parts. The transponder chip which is passive (no battery needed) and it is read by the cars immobiliser PAT's system and if it is correct then the car can be started. The second part of the keyfob is the transmitter for the Lock/Unlock of the doors which is an active system and does require a battery. The new keyfob will need to be programmed in.

5 minutes ago, unofix said:

Well the idea is fine, I'm just not sure how easy it is to get the transponder chip out of your original key. From the photo it does look like you might be able to gentally leaver it out.

As far as knowing if that particular keyfob will work with your car it's difficult to say without knowing what your normal remote keyfob looks like. Of course you will need to programme it in to the car using Forscan as I think the old system of being able to code them in to the car using the ignition turns may not work on your model.

 

I guess I need to wait until the new assembly I ordered to arrive. 
 

The other key has circuit board to open and close. I am not sure if that board has been programmed for this car or it just works with the transponder. Guess I need to look into how transponders work 🙂 

The transponder chip has nothing to do with the lock/unlock of the car, it is only for the immobiliser.

Your exsisting remote key is already programmed in to the car, to allow the locking/unlocking to work. You will need to programme in the new key, you can do that and test it without the need to transfer the transponder chip. Then once you have the keyfob working the locks you can then go-ahead and take the transponder chip out of your spare key.

2 minutes ago, unofix said:

The transponder chip has nothing to do with the lock/unlock of the car, it is only for the immobiliser.

Your exsisting remote key is already programmed in to the car, to allow the locking/unlocking to work. You will need to programme in the new key, you can do that and test it without the need to transfer the transponder chip. Then once you have the keyfob working the locks you can then go-ahead and take the transponder chip out of your spare key.

Oh! I get it now.

I will see if I can program the new key fob. Hopefully it won’t cost me too much. 
 

thank you 🙂 

3 minutes ago, JB0702 said:

Hopefully it won’t cost me too much

About £70 if you take it to a dealer or use an auto locksmith.

I will see if I can find the instructions on how to do it via the ignition -- BUT the function to be able to do that was removed by Ford many years ago. Your car might be old enough that it can still be done that way. Otherwise you can do it yourself usinf the software called ForScan and an ELM327 lead to connect to the OBDII port.

 

1 minute ago, unofix said:

 

Thank you! I just found the same video as well. Guess I will try this and see if I can get it to work 🙂 

On 9/28/2021 at 9:09 PM, unofix said:

About £70 if you take it to a dealer or use an auto locksmith.

I will see if I can find the instructions on how to do it via the ignition -- BUT the function to be able to do that was removed by Ford many years ago. Your car might be old enough that it can still be done that way. Otherwise you can do it yourself usinf the software called ForScan and an ELM327 lead to connect to the OBDII port.

I’ve done it! Got the new key fob for £8 and key cut was another £9 🙂 I followed the YouTube video to program it and put the old immobiliser chip into a new one. It works like a magic. Thank you! 

£17. Well done. My mark 8 key cost the dealer (warranty,) £128 without cutting a key.

That's what happens to people who take the trouble to follow the instructions!