UK-POLOS.NET - THE VW Polo Forum

Has anyone ever heard of the engine managment light coming on when the catalytic converter is removed from your car??? Even though it was a week since it was removed.

Yes I have, it usually comes on whenever the cat is removed. But the ones I have seen have had the lambda probe/oxygen sensor removed too.

Perhaps the one on your car is still in your decat'd pipe.

The probe was put back in the pipe. will removing this, turn off the engine management light or will i have to go to vw to reset it( which I dont wanna do )

I would have a quick look to check if its connected properly i.e. the wires not broken etc.

Then secondly disconnect your battery and leave it for a bit...like an hour or so (30 mins minimum I think)...this usually sorts most minor problems out. When you do this, your one touch windows might loose memory, simply get them working again by holding the button down all the way when putting your windows down. Job done.

Otherwise unfortunately resetting it is the only option, though I dont know if it'll simply come back on.

I know someone with a highly tuned Focus ST 2.5T, and they haven't bothered to get the light taken off (its still there).

its just because the lamda probes sense too high a reading due to the de cat pipe

this being why i opted for a high flow cat from milltek to go with my high flow milltek system, you may lose about 2 bhp if that by having the high flow cat apposed to the de cat but you also lose the problems a decat brings and emission problems come mot time too

Ill reset the ecu tonight, from reading thro other websites it seems it will just come back on after a few hundred miles again. Think I will put the cat back in after i get back my holiday, dont wanna be resettin ma ecu all the time.

i know it will work out a bit more in the long run, but have you considered a high flow cat

you dont necessarilly have to change the full exhaust if you would rather not, just get a universal one, or match up a branded one to the std exhaust width, which i believe is a 2 1/4 inch bore

i just got the milltek as it fitted straight to my milltek system which is a 2 3/4 inch bore

Dont want to go changing it again. gettin fed up with it. Was askin a couple a boys at work, one knows his suff with VAG cars says if i remove the sensor rom the pipe and clip it out the road, and plug the hole it will clear the fault, as the only reason it is showing is the 2nd sensor is getting the same reading from the 1st one. he other guy says it wont work as the ecu is programmed to get certain readings, ie 1st sensor 2V 2nd sensor 0.5V. Can anyone back either of them up?????