Decat and Check Engine light / Limp mode

[Flibbib]

Hi all. I'm going to have a decat fitted (potentially tomorrow) and need to look into managing it properly. I know the check engine light will come on, which I can live with, but will this actually put the car in limp mode?

As far as I understand, either the Focus mk2 runs normally, or limp mode where it states "acceleration reduced". Is this right? 

I'm hoping the light will come on but it will run as if nothings happened. Can anyone clear this up for me? I'll probably screw the second lambda sensor into the back of the cat, unless anyone has a better idea.

 

Thanks in advance guys

[DJ_Andy_M]

You're a TDCi? Potentially s-crewing (seriously? Why is that sensored?) with the cat will throw your car into limp mode yes. Also I don't know what other adverse affects you will have other than breaking the law and failing your emissions/smoke test at MOT.

[WES180]

I fitted a decat to my 56 plate Mondeo ST TDCi and it didnt cause any problems including passing the MOT. That was back in 2008 though so the MOT legislation might well have changed now.

[Flibbib]

Just to clear anything up, it's for off road use, and I want to know whether the engine light will actually cause a loss of power or fuelling / mixture issues. Also is it possible to remove the cat / manifold without removing the sub frame? Also it's a petrol.