Just had the engine light come on in my 2005 Golf GTI. After plugging in my OBD2 reader it comes up with a P0420 error code. Looking online this error is Catalyst System Efficiency Below Threshold.
Has anyone had this error before and if so what did they do to fix it?
Could be a number of things and I wonder if it is the Catalytic converter?
Any help would be much appreciated.
Thanks
