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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 23206
Experience:  BEng hons Mech engineering, in auto industry 22 years
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We have a Fabia mk2. Having removed the front cat and

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We have a Fabia mk2. Having removed the front cat and replacing the rear one the engine management light has now come on. Do you think the two things are related


If you have removed the front cat and not changed the ECU flash calibration then yes you'll get a check engine light as the O2 sensors in the exhaust will be showing the exhaust emissions are well out of range

so if this is a track car where you don't have to run the cat then you'll need an ECU calibration change to over come this

however a road car MUST have a cat or you're breaking the law and it certainly won't pass the MOT

can I ask why you have removed it?

Customer: replied 10 months ago.
It is my sons car and he is not exactly flush with money. The mechanic who did it seemed to think it would run ok. It does sound a bit noisier now. Should we pay up and replace the front cat ?


if the front cat was clogged / broken up then this can really hurt engine power so you sometimes remove the cat as part of the diagnostic process

but you do need a cat

how about a good used item?

Customer: replied 10 months ago.
i will look for one and get it fitted as soon as possible. Thanks for your help Matt

no problem

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