2001 Mazda Protege P0421

2001 MAZDA PROTEGE

144,000 MILES

GUAYAS007

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2 POSTS
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Mil on, went to check for code, it show p0421, last year replaced cat. Coil packs, and cables +sparks, found different code and I replaced all this parts per dealer. And now this code..???? Another cat????

Sep 19, 2013 at 8:52 AM

HMAC300

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48,601 POSTS

I kinda doubt it is the cat if it was replaced last year unless you put a ton of miles on it. but it cold be a bad O2 sensor, and exhaust leak out of the O2 either front or back of cat or an exhaust leak

Sep 19, 2013 at 9:32 AM

GUAYAS007

MEMBER
2 POSTS

Thanks for this info, I will check this weekend. :)

Sep 20, 2013 at 8:27 AM