sylvernight
New member
I have a 2004 Mazda 6 v6. She was running a little sluggish, but got better when I replaced her ignition coils. Now, the "check engine" light has been coming on and off about every other day. My friend checked with his computer, and got the code, "P0421." Can anyone provide insight on what this means? Unfortunately, I live overseas, and there are no Mazda dealerships nearby, so I have to go by this code and whatever help the local shop can provide.
P.S. I can order parts online.
P.S. I can order parts online.