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2003 Mazda MX-5 Miata Cloth 2dr Conv 5-Spd Manual

2003 Mazda MX-5 Miata
Trim Info:
Rear Wheel Drive, 2 Door Convertible, Two Seater
23 mpg city / 28 mpg hwy
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November 23, 2012, 12:02 pm

Tom T
 

Question: Check engine code P0421

This code shows "Catalyst below Threshold". What is general fix for this, and how much?
thomp216@yahoo.com


December 4, 2012, 10:42 am

Elizabeth K
Expert Mechanic

It can be caused by about 3 different things, so you'll need to troubleshoot the cause before getting an estimate. Here's some info on the code and the possible causes:
http://www.obd-codes.com/p0421


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