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p0420

  1. Exhaust leak and P0420 code (catalyst efficiency)

    MK4
    Bought the 01 Jetta Tuesday. On my way home noticed that the HVAC system was blowing exhaust into the cabin (or at least it sure smelled like it). On the way to work today (110 miles ownership) the engine light came on. Auto Zone ran the diagnostics and returned a P0420 code. I realize what the...
  2. P0420 & After-market CATs

    MK4
    Hello, I have a 2002 VW Jetta Wagon 1.8T (111,000 miles). Recently, I 've been getting the P0420 code and nothing else. If I clear it, it comes back in a couple of days (~100 miles). Previously I had several bad (recalled) ignition coils. My mechanic figures that unburnt fuel got...
  3. i need some technical knowledge guys

    MK4
    my car is a 2000 mk4 2.0 jetta 130k mileage i get po422 cat efficiency code these days n i only have few more days left for emissions test. catalytic converter rattles and needs to be replaced i think (after i got the code my opinion was like this n im open to any other idea) the owner before...
  4. 01 VR6 - P0420 - cat or 02?

    MK4
    I've been searching and reading the posts. Some people seem to think that replacing the cat is the fix, while others say that replacing the 02 sensors is the fix. Is there a way to tell for sure without just replacing parts to see what works. Don't wanna spend a lot of money if I don't have...
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