jroberts 312
1/25/2006 2:52:32 PM
Been researching this error code for my 2001 626 ES. Is this a definite bad catalytic converter? Could this be an O2 sensor? If so, which one. There are two. One in front
of converter and behind. Can someone help?
babyhuey
1/26/2006 3:14:09 AM
Since you have the ES model am assuming that the engine is the 2.5l V6?? Assuming also if is a V6 then must be a california spec emission as the Federal only has one catalytic converter and would have set a P0420. The P0421 indicates the right bank catalyst efficiency is below limit. A faulty oxygen sensor is very, very rarely responsible for efficiency codes with Mazda. They all have codes themselves in case a fault is detected. The only Mazda I am aware of that has this problem is the 1997-2000 Millenia S which Mazda claims that the rear O2 sensors could be overly sensitive to set this code.
The front or upstream O2 is used for rich/lean detection and rear is only used as a catalyst monitor. You are aware that the cat converters are covered under emissions warranty for 8 years or 80,000 miles? Hopefully you are under those limits.
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jroberts 312
2/27/2006 3:23:36 PM
sorry for the long delay. The mazda has a 4cyl 2.0 engine in it. Unfortunately the mileage has just passed 80 K miles. One muffler shop told me the pre -cat is what is bad. He quoted me $838 dollars just for the pre-cat. Is this guy trying to rip me off?
