Mazda Repair: Catalyst System efficiency, catalyst system, o2 sensor

Question
Code P0420 showed up on my 98 Protege with OBD 11 checker.
Catalyst System Efficiency Below Threshold(Bank1)
Translation please. Car seems to run fine.


Answer
Hi Slw thanks for asking.
This code just means that the second O2 sensor is seeing more unburnt fuel and emmisions then it should be. Meaning the O2 sensor fluctuates more, just like the first O2 sensor does. These are common problems with theses protege's. When this code comes up you HAVE TO replace the catalytic converter. Unfortenatly these cat's are very expesive. 1000 dollars in canadian funds. But if the vehicle doesnt have too high of milegae check with a mazda dealer because they where recalled in some areas and some dealers change them under an unlimited warrany. This is only in some areads though.....
Good luck
Chris P