Code P0430 | Ford Explorer Forums - Serious Explorations

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Code P0430

Mounty 09

Well-Known Member
March 5, 2007
Reaction score
City, State
Nothern IN
Year, Model & Trim Level
1997 Mountaineer
My check engine like came on in my 97 Mountaineer with the 5.0. Went to advance auto to read the codes and came back and said "P0430 Catalyst efficiency below threshold" What is wrong?


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Dose anybody know what this code means??

Just got one on my 98 ex 5.0. Good excuse to get the cats changed and a free-er flowing exhaust installed! Looking for a good muffler replacement as well. Plus i need it to finish the inspection here in Houston.

COULD be the cat on the pass side is getting old, or your bank 2 sensor 2 02 sensor could be on its way out.

You can try swapping 02 sensors from d to pass sides and see if code returns

you can check for leaks in the exhaust as well

I wouldnt buy anything yet, clear the code and see if it returns, do some testing and then if the cat is indeed on its way out consider replacing both primary cat converters at the same time

Good trouble shooting tips 410. I already had mine narrowed to the bank 2 (passenger side) sensor 2 (after primary cats) and had it replaced, cleared everything up and passed inspection.

Still looking to get the exhaust upgraded, but saved a $400-$500 "rush-job" that some shops give you, "We've got bad news for you!" Found several systems by searching here for about $250-$300, and a weekend job!

I have found this to be the most informative and helpful forums dedicated to explorers. Very glad I've reduced the fleet to just the two explorers (1998 5.0 and 2005 4.0) Loving it more that i can find inexpensive and invigorating ideas to keep the vehicles fresh and running well