Engine code?

[mothergoose]

Hi,

I need to replace the O2 lambda sensor in my car and my hubby says he'll have a go doing it himself. I've looked on http://www.gendan.co.uk/oxygen_lambda_sens...ord_Fiesta.html for the sensor, but how can I find out the engine code for my car? I've got 2004 Fiesta, 1.25 i Duratec 16v engine, but the website wants the engine code, I can't find a plate under the bonnet at the back of the engine like the manual says, there is a plate on the inside of the drivers door, but there is no code like the ones on the website eg ZH12.

I would also appreciate any instructions on how to do this procedure.

Thanks for any help or advice given, I am grateful :D

[Russ]

Basically when you get a new sensor, uncouple the wires, unscrew the old one and screw in the new one reconnecting the wires.