2001 Mazda Millenia Check Engine Light Assistance

Hello and thanks for the donation!


The first two codes (0421 and 0431) are oxygen sensor fault codes, however, since you state you had them replaced recently it is most likely a faulty catalytic converter causing these codes to appear. Code 1522 is a transmission fault code and refers to the variable resonance induction system (VRIS) solenoid valve #2 circuit malfunction.

[quote:e997975f20="bluelightnin6"]Hello and thanks for the donation!


The first two codes (0421 and 0431) are oxygen sensor fault codes, however, since you state you had them replaced recently it is most likely a faulty catalytic converter causing these codes to appear. Code 1522 is a transmission fault code and refers to the variable resonance induction system (VRIS) solenoid valve #2 circuit malfunction.[/quote:e997975f20]


Thanks how will i know which catalytic converter is bad?? I don't want to pay an auto shop 100 dollars just to find out which one. By those codes is there anyway to tell??? Is it the front one or the rear catalytic converter?? Also does it have to be direct fit or universal?? Or is it better to just have direct fit?? Is it possible i could get one from another mazda millenia?? Or does it have to be brand new?? Please let me know thanks

You can get a used one from a salvage yard as long as its for your specific vehicle. I recommend direct fit if buying new, not a universal one. Can't tell which one from the codes, the converters will need to be flow tested to show which is faulty.