The ecu on my fabia has finally given up, and now i need to replace it, i know i have to do something with the imobiliser code but besides that can i just take one out and put a new one in?

it will need coding to the dash and the key i think, dont think its as easy as one in one out,

If you are replacing it with a used one, you'll also need the immobiliser code for the donor vehicle.

knew i'd have to do the imobiliser code, but what do you mean by 'coding it to the dash'?

The Immo is contained within the dash insert so effectively you need to pair the two together.

It can be done with a registered version of VAG-COM/VCDS if you have the 4 digit SKC from the doner and the 4 digit SKC from your car.

If not then really you'll be heading down the main dealer route.

The Immo is contained within the dash insert so effectively you need to pair the two together.

It can be done with a registered version of VAG-COM/VCDS if you have the 4 digit SKC from the doner and the 4 digit SKC from your car.

If not then really you'll be heading down the main dealer route.

so all i need to do is buy an ecu, get the code from my current one, get the new one and set it to that code and then it should work?

Yes in theory but not so simple as that I'm afraid.

You need to have the 4 digit SKC (Secret Key Code) for both yours and the new one. These can sometimes be 'extracted' but the doner would need to be powered up as well which rules out most scrap cars.

is the key stored anywhere else, on my spare keys there's a 4 digit code on them is that it? also could i unplug my ecu plug the new one in extract the code and then go from there?

They code would need to be extracted from the dash insert of the Doner. If you have a plastic tag with a small sticker on it containing a 4 digit number then there is every chance that is your SKC.

If you bought the dash insert of the Doner with the ECU then that might make more options available to you.

so assuming that i get the code for the new ecu aswell then how would i do the transfer, do i copy the data from the old one to the new one or something?

What is wrong with the ECU?

so assuming that i get the code for the new ecu aswell then how would i do the transfer, do i copy the data from the old one to the new one or something?

There is a procedure available to VAG-COM/VCDS owners.

What is wrong with the ECU?

i've been getting repeated immobiliser faults and today it gave me error code 18048 which i've been told means replace it

So you have an EEPROM error, what Fabia is it?

2001 1.4 classic 8v