Fault code 16804 (P0420) catalyst system efficiency too low

[rhencullen1989]

Hi, as heading I had a scan done a while back and the following error came up. There is no light on the dash, could this be a MAF problem or pre/post cat oxygen sensor issue, the car does do quite a few short journeys and the mrs uses Sainsburys fuel. Car is 1.8T Quattro S line 190 BEX engine code. Please help me with this issue!

[mkc]

Hi, as heading I had a scan done a while back and the following error came up. There is no light on the dash, could this be a MAF problem or pre/post cat oxygen sensor issue, the car does do quite a few short journeys and the mrs uses Sainsburys fuel. Car is 1.8T Quattro S line 190 BEX engine code. Please help me with this issue!

I have a B6 2.0 with 150,000 on the clock. My engine light is on most of the time, due to 3 errors Ive been getting for several years. I clear it at MOT time. Anyway, I went to switch the Engine Light off a few weeks before my MOT, did a quick scan and my car gave the same fault as yours, in amongst my usual running too rich, too lean bank one errors.

I was worried that it would fail the MOT as I too thought it was related to sensors, MAFs, oxygen and emmissions etc. It passed the MOT so it seemed to have no impact to that. I cleared it, and its not come back.

When it was warning me, the car ran fine. No side effects to performance or fuel consumption. I would clear it down, and see if it comes back. Im sure those with more knowledge will tells us both what the problem is and the fact we should resolve it, but for me, its been ok at the moment (as a one off)