Engine Management System Light stays on ! Why? Ford Focus '53 plate?

is the new cat a ford one or a pattern part,if it is a pattern part this could be the problem as pattern cats are half the size and this causes problems with the emissions. we have this alot as we are a ford dealer.hope this helps.

paul c
November 2009

Get the diagnostic trouble codes read, then tell us what they are. Anything else is guesswork.
It might be worth taking it to a Ford dealer to get it checked on proper Ford diagnostics which can read all the codes. The generic readers the AA use dont always get everything.
I usually advise against using dealers as they are too expensive, but given how much money you have already wasted fitting new parts unnecessarily, lets try and fix it properly this time.

fred
November 2009