Catalyictic converter failure

Asked by Oct 11, 2017 at 05:49 PM about the 2005 Jeep Grand Cherokee Laredo 4WD

Question type: Maintenance & Repair

6 months ago I bought my Jeep Grand
Cherokee , in the paper work the original
owner gave me the cat BANK 1 has been
replaced , when I bought it I had to replace
that same cat (bank1) now that cat I
recently I just got done 6 months ago is
failing again which has gave me a p0420
code :( my question is WHERE DO I START
to look for what's causing the same cat to
fail PLEASE thank you in advance!!!

6 Answers


Aftermarket catalytic converters do not last as long first of all. Second, this code doesn’t necessarily mean that you have a bad converter. It might be an exhaust leak. What is the temperature going into cat and coming out?

1 of 1 people found this helpful.

It's pretty apparent and the noise it makes it noticeable too, the cat has also changed color, I believe I may have an exhaust leak (I know nothing about cars) but the new muffler I put in is definitely showing signs of burns, where do I check for an exhaust leak? I have no clue how may I determine?


For burn purposes, get under car cold and start up and find puffing joints/connections that are leaking. Also louder noise can help find leak.

Really appreciate you , any other tips hints you can throw my way ??


You should also have the vehicle live data scanned, there maybe a problem with fuel trim, if it cycling way too much there could be an internal engine vacuum leak or bad or leaking injectors on one bank. HTH

1 of 1 people found this helpful.

It's killing way to much gas, LIKE unbelievably before i even thought about an exhaust leak I thought about the injectors. I need to get those checked out as I have not had or checked those myself since I've bought it

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