Question about 2005 Audi A3

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Management light Cat problem code

2004 Audi Cab 1.8T, Engine management light on, diagnostics point to Cat, new cat fitted (not audi) twice, no go so garage changed final lamba after cat, definetly it they said back onagain after 20 miles. No performance or economy probs.
Just......annoying Getting desparate now after much £££ spent!

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  • lbailey388 Jan 18, 2009


    Thanks vet much for the reply's

    The fault code is 16804 CAT SYSTEM CYL BANK 1P0420

  • Roberta Smith
    Roberta Smith May 11, 2010

    what was the code(s) you were getting ?




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You mentioned a non genuine cat being fitted. That in itself is not too much of a problem, however, non genuine oxygen sensors are. There is a huge difference in quality between the genuine article and cheep alternatives on the after market. I very much suspect your fault code has been tripped by such a replacement part. Exceptionally complex engine management control systems just cant recognise the electronic info thats being sent by non-gen sensors, so its a false economy to fit these. Also one thing to bear in mind for the future is to avoid using super market fuels. Its a common belief that all fuels are the same and it all comes from the same tankers, etc etc. This is absolute rubbish. Its like comparing a 20 year old single malt Scottish Whiskey with a Happy Shopper bargain blend. It may look the same, but there's simply no comparison. Prolonged use of these cheep fuels will produce long term running problems. Also dont forget, there are pre and post catalytic converter oxygen sensors on your car, so the bills can get expensive. Good luck

Posted on Jan 17, 2009


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